diff --git a/.github/workflows/e2e.yml b/.github/workflows/e2e.yml
index 7a5eff241e6..00739f36350 100644
--- a/.github/workflows/e2e.yml
+++ b/.github/workflows/e2e.yml
@@ -17,6 +17,10 @@ on:
         description: JSON array of changed specs; empty runs the full suite
         required: false
         type: string
+      ssh_source_changed:
+        description: '"true" when the PR touches SSH execution source; gates the Docker-SSH lane'
+        required: false
+        type: string
   workflow_dispatch:
     inputs:
       ref:
@@ -221,14 +225,21 @@ jobs:
   ssh-docker-watcher-isolation:
     name: ssh docker watcher isolation
     needs: build
+    # Why ssh_source_changed first: this lane used to trigger on SSH source only as a side
+    # effect of one route listing a startup-readiness spec — pruning that spec would have
+    # silently retired the whole lane. The signal is now derived from the SSH routes directly.
+    # The two spec clauses stay for their honest purpose: changed-e2e hands these specs to this
+    # lane, so editing one must still run it here.
     if: >-
       inputs.test_files == '' ||
+      inputs.ssh_source_changed == 'true' ||
       contains(inputs.test_files, 'tests/e2e/ssh-startup-exec-readiness.spec.ts') ||
       contains(inputs.test_files, 'tests/e2e/paired-startup-exec-readiness.spec.ts')
     runs-on: ubuntu-latest
-    # Why 35: the parking, retention, startup-exec, and paired parity specs run
-    # serially on isolated Electron/SSH fixtures after watcher isolation.
-    timeout-minutes: 35
+    # Why 60: this lane now also runs the remaining Docker-SSH specs serially. They average
+    # ~18s but several budget 4-10 minutes per test, so a slow run lands far above the old 35
+    # — and the sharded lanes already show that a lane which times out is a lane nobody trusts.
+    timeout-minutes: 60
 
     steps:
       - name: Checkout
@@ -260,6 +271,14 @@ jobs:
         if: always()
         run: xvfb-run --auto-servernum env SKIP_BUILD=1 ORCA_E2E_FORWARD_APP_LOGS=1 pnpm run test:e2e:ssh-docker-terminal-parking
 
+      # Why here rather than the sharded lanes: the shards set no ORCA_E2E_SSH_DOCKER, so every
+      # spec below skipped itself while the shard still reported green. Running them on this one
+      # VM pays the fixture image build once instead of ten times, and keeps an SSH regression
+      # legible as an SSH-named failure.
+      - name: Run remaining Docker SSH E2E
+        if: always()
+        run: xvfb-run --auto-servernum env SKIP_BUILD=1 ORCA_E2E_FORWARD_APP_LOGS=1 pnpm run test:e2e:ssh-docker
+
       - name: Upload watcher isolation traces
         if: failure()
         uses: actions/upload-artifact@v7
diff --git a/.github/workflows/pr.yml b/.github/workflows/pr.yml
index 9fbe35a173f..9f3b14f5903 100644
--- a/.github/workflows/pr.yml
+++ b/.github/workflows/pr.yml
@@ -804,6 +804,7 @@ jobs:
     outputs:
       should_run: ${{ steps.filter.outputs.should_run }}
       test_files: ${{ steps.filter.outputs.test_files }}
+      ssh_source_changed: ${{ steps.filter.outputs.ssh_source_changed }}
     steps:
       - name: Checkout
         uses: actions/checkout@v6
@@ -826,6 +827,11 @@ jobs:
           # authorities, exclusions, and sentinels without evaluating workflow shell.
           TEST_FILES_JSON="$(printf '%s\n' "$CHANGED" | node config/scripts/pr-e2e-source-routing.mjs)"
           echo "test_files=$TEST_FILES_JSON" >> "$GITHUB_OUTPUT"
+          # Why a separate signal: the Docker-SSH lane must trigger on SSH source, not on a
+          # spec name surviving in a route's list. Same routes, so the two cannot drift.
+          SSH_SOURCE_CHANGED="$(printf '%s\n' "$CHANGED" | node config/scripts/pr-e2e-source-routing.mjs --ssh-source)"
+          echo "ssh_source_changed=$SSH_SOURCE_CHANGED" >> "$GITHUB_OUTPUT"
+          echo "SSH source changed: $SSH_SOURCE_CHANGED"
           if [ "$TEST_FILES_JSON" != '[]' ]; then
             echo "should_run=true" >> "$GITHUB_OUTPUT"
             echo "Changed E2E specs: $TEST_FILES_JSON"
@@ -844,6 +850,7 @@ jobs:
     uses: ./.github/workflows/e2e.yml
     with:
       test_files: ${{ needs.e2e-paths.outputs.test_files }}
+      ssh_source_changed: ${{ needs.e2e-paths.outputs.ssh_source_changed }}
 
   verify:
     if: always()
diff --git a/config/scripts/pr-e2e-gate-contract.test.mjs b/config/scripts/pr-e2e-gate-contract.test.mjs
index 665edd01ec0..8cd622b300c 100644
--- a/config/scripts/pr-e2e-gate-contract.test.mjs
+++ b/config/scripts/pr-e2e-gate-contract.test.mjs
@@ -1,9 +1,14 @@
-import { existsSync, readFileSync } from 'node:fs'
+import { existsSync, readdirSync, readFileSync } from 'node:fs'
 import { join, resolve } from 'node:path'
 import { parse as parseJsonc } from 'jsonc-parser'
 import { describe, expect, it } from 'vitest'
 import { parse as parseYaml } from 'yaml'
-import { PR_E2E_SOURCE_ROUTES, selectPrE2eSpecs } from './pr-e2e-source-routing.mjs'
+import {
+  hasSshSourceChange,
+  PR_E2E_SOURCE_ROUTES,
+  selectPrE2eSpecs,
+  SSH_SOURCE_ROUTE_IDS
+} from './pr-e2e-source-routing.mjs'
 
 const projectDir = resolve(import.meta.dirname, '../..')
 const prWorkflow = parseYaml(readFileSync(join(projectDir, '.github/workflows/pr.yml'), 'utf8'))
@@ -209,6 +214,8 @@ describe('PR E2E gate contract', () => {
       'src/main/providers/ssh-',
       'src/main/ipc/pty',
       'src/relay/',
+      'src/shared/ssh-',
+      'src/renderer/src/store/slices/direct-ssh-',
       'src/renderer/src/components/terminal-pane/remote-runtime-'
     ]
     for (const authority of sshSourceAuthorities) {
@@ -217,10 +224,24 @@ describe('PR E2E gate contract', () => {
       )
     }
 
+    // Why named files rather than prefixes: these seams are single modules, and a prefix
+    // here would route their unrelated neighbours.
+    for (const file of [
+      'src/main/runtime/public-ssh-state.ts',
+      'src/renderer/src/startup/ssh-startup-reconnect.ts',
+      'src/renderer/src/store/slices/ssh.ts'
+    ]) {
+      expect(selectPrE2eSpecs([file]), file).toContain(
+        'tests/e2e/ssh-docker-reconnect-pane-restore.spec.ts'
+      )
+    }
+
     const mappedSpecs = [
       'tests/e2e/pty-input-write-queue-ssh.spec.ts',
       'tests/e2e/ssh-cold-activation-restore.spec.ts',
       'tests/e2e/ssh-docker-reconnect-pane-restore.spec.ts',
+      'tests/e2e/ssh-port-forward-lifecycle.spec.ts',
+      'tests/e2e/ssh-reconnect-tab-destruction.spec.ts',
       'tests/e2e/ssh-startup-exec-readiness.spec.ts',
       'tests/e2e/ssh-terminal-window-wake-stale-grid-repro.spec.ts'
     ]
@@ -249,6 +270,140 @@ describe('PR E2E gate contract', () => {
     expect(changedInstall.run).toContain('openssh-client')
   })
 
+  it('routes direct-SSH workspace and tab restore from its unnamed source seams', () => {
+    // Why by name: none of these carry "ssh", so the SSH authorities above never reach them
+    // — a closed-tab tombstone and a dropped default-tabs marker both shipped through it.
+    for (const file of [
+      'src/renderer/src/hooks/remote-workspace-session-merge.ts',
+      'src/main/ipc/remote-workspace-snapshot-normalization.ts',
+      'src/renderer/src/lib/worktree-initial-terminal-seeding.ts',
+      'src/renderer/src/lib/worktree-default-terminal-tabs.ts',
+      'src/shared/remote-workspace-session-projection.ts',
+      'src/renderer/src/components/terminal/initial-terminal.ts'
+    ]) {
+      const specs = selectPrE2eSpecs([file])
+      expect(specs, file).toContain('tests/e2e/ssh-cold-activation-restore.spec.ts')
+      expect(specs, file).toContain('tests/e2e/ssh-reconnect-tab-destruction.spec.ts')
+    }
+
+    expect(
+      selectPrE2eSpecs(['src/renderer/src/hooks/remote-workspace-session-merge.test.ts'])
+    ).toEqual([])
+  })
+
+  it('triggers the Docker-SSH lane from SSH source, not from a spec name', () => {
+    // The behavioural half of the invariant, and the part that actually matters: an SSH source
+    // edit is recognised as one, through the same routes that select the specs.
+    for (const file of [
+      'src/main/ssh/connection.ts',
+      'src/relay/pty-handler.ts',
+      'src/renderer/src/store/slices/direct-ssh-pane-retry-ledger.ts',
+      'src/renderer/src/hooks/remote-workspace-session-merge.ts',
+      'src/main/ipc/remote-workspace-snapshot-normalization.ts'
+    ]) {
+      expect(hasSshSourceChange([file]), file).toBe(true)
+    }
+    for (const file of [
+      'src/main/git/git-status.ts',
+      'src/renderer/src/components/tab-bar/BrowserTab.tsx',
+      'src/main/ssh/connection.test.ts'
+    ]) {
+      expect(hasSshSourceChange([file]), file).toBe(false)
+    }
+
+    // Why: the signal must stay derived from the routes. A route id that no longer exists would
+    // silently narrow it to nothing.
+    for (const id of SSH_SOURCE_ROUTE_IDS) {
+      expect(
+        PR_E2E_SOURCE_ROUTES.map((route) => route.id),
+        id
+      ).toContain(id)
+    }
+
+    // Why text and not structure: a job `if:` is only ever available as a string. The strongest
+    // available assertion is that the source signal is its own disjunct, so the lane no longer
+    // depends on a spec name surviving in a route's spec list.
+    const sshLaneCondition = e2eWorkflow.jobs['ssh-docker-watcher-isolation'].if
+    expect(sshLaneCondition).toContain("inputs.ssh_source_changed == 'true' ||")
+
+    expect(e2eWorkflow.on.workflow_call.inputs.ssh_source_changed.type).toBe('string')
+    expect(prWorkflow.jobs['e2e-paths'].outputs.ssh_source_changed).toBe(
+      '${{ steps.filter.outputs.ssh_source_changed }}'
+    )
+    expect(prWorkflow.jobs.e2e.with.ssh_source_changed).toBe(
+      '${{ needs.e2e-paths.outputs.ssh_source_changed }}'
+    )
+    expect(filterStep.run).toContain('pr-e2e-source-routing.mjs --ssh-source')
+    expect(filterStep.run).toContain('ssh_source_changed=$SSH_SOURCE_CHANGED')
+  })
+
+  it('gives every Docker-gated SSH spec a lane that runs it', () => {
+    // Why this shape: the sharded lanes set no ORCA_E2E_SSH_DOCKER, so a Docker-gated spec
+    // that no runner names runs nowhere and still reports green — the silent skip this file
+    // exists to prevent. Asserting reachability rather than a literal keeps that true when
+    // the lanes move.
+    // Why these two are exempt: each needs something CI cannot give it, recorded in
+    // run-ssh-docker-e2e.mjs so the gap stays legible rather than looking like coverage.
+    const unreachableSpecs = new Set([
+      'tests/e2e/ssh-docker-relay-perf.spec.ts',
+      'tests/e2e/ssh-codex-display-artifacts-repro.spec.ts',
+      'tests/e2e/ssh-docker-bulk-open-freeze-repro.spec.ts'
+    ])
+    // Why comments are stripped: this file's own runner lists the two exempt specs by name in a
+    // prose comment. A substring scan over raw text would count any spec merely *discussed* in a
+    // runner as claimed by it -- the silent skip this assertion exists to catch, re-entering
+    // through the documentation.
+    const stripComments = (text) =>
+      text.replace(/\/\*[\s\S]*?\*\//g, '').replace(/^\s*\/\/.*$/gm, '')
+    const laneRunners = [
+      'run-ssh-docker-e2e.mjs',
+      'run-ssh-docker-watcher-isolation-e2e.mjs',
+      'run-ssh-docker-terminal-parking-e2e.mjs'
+    ].map((file) => stripComments(readFileSync(join(projectDir, 'config/scripts', file), 'utf8')))
+
+    // Why a comparison and not the bare name: preview and demo specs cite the flag in a
+    // "how to run me" comment without gating on it. Why a regex rather than one literal: an
+    // equally-valid spelling (double quotes, or a `!==` guard) would escape a fixed-string scan
+    // and the spec would silently leave the contract.
+    const dockerGateExpression = /ORCA_E2E_SSH_DOCKER\s*[!=]==\s*['"]1['"]/
+    const dockerGatedSpecs = readdirSync(join(projectDir, 'tests/e2e'))
+      .filter((file) => file.endsWith('.spec.ts'))
+      .map((file) => `tests/e2e/${file}`)
+      .filter((spec) => dockerGateExpression.test(readFileSync(join(projectDir, spec), 'utf8')))
+    expect(dockerGatedSpecs.length).toBeGreaterThan(0)
+
+    const unclaimed = dockerGatedSpecs.filter(
+      (spec) => !unreachableSpecs.has(spec) && !laneRunners.some((runner) => runner.includes(spec))
+    )
+    expect(
+      unclaimed,
+      `Docker-gated specs claimed by no lane runner: ${unclaimed.join(', ')}`
+    ).toEqual([])
+
+    // Why: an exemption that outlives its spec would quietly excuse a real gap.
+    for (const spec of unreachableSpecs) {
+      expect(dockerGatedSpecs, spec).toContain(spec)
+      // Why also assert absence from every runner: `unreachableSpecs` short-circuits the
+      // unclaimed check above, so a spec could be documented as exempt while a runner still
+      // invokes it -- an exemption that reads as coverage removal but changes nothing, and a
+      // lane that stays red for a reason the file says it excluded.
+      for (const runner of laneRunners) {
+        expect(runner.includes(spec), `${spec} is exempt but still invoked by a lane runner`).toBe(
+          false
+        )
+      }
+    }
+
+    const laneStep = e2eWorkflow.jobs['ssh-docker-watcher-isolation'].steps.find(
+      (step) => step.name === 'Run remaining Docker SSH E2E'
+    )
+    expect(laneStep.run).toContain('test:e2e:ssh-docker')
+    // Why: the added serial tests, several budgeting 4-10 minutes each, do not fit the old 35.
+    expect(
+      e2eWorkflow.jobs['ssh-docker-watcher-isolation']['timeout-minutes']
+    ).toBeGreaterThanOrEqual(60)
+  })
+
   it('scopes the VM rollback oracle to the PR range and recipe schema authorities', () => {
     expect(rollbackStep.run).toContain('--merge-base "$BASE_SHA" "$HEAD_SHA"')
     expect(rollbackStep.run).toContain('src/shared/ephemeral-vm-recipes.ts')
diff --git a/config/scripts/pr-e2e-source-routing.mjs b/config/scripts/pr-e2e-source-routing.mjs
index 04f570f0094..108a4d5ab10 100644
--- a/config/scripts/pr-e2e-source-routing.mjs
+++ b/config/scripts/pr-e2e-source-routing.mjs
@@ -18,12 +18,32 @@ export const PR_E2E_SOURCE_ROUTES = [
       'tests/e2e/pty-input-write-queue-ssh.spec.ts',
       'tests/e2e/ssh-cold-activation-restore.spec.ts',
       'tests/e2e/ssh-docker-reconnect-pane-restore.spec.ts',
+      'tests/e2e/ssh-port-forward-lifecycle.spec.ts',
+      'tests/e2e/ssh-reconnect-tab-destruction.spec.ts',
       'tests/e2e/ssh-startup-exec-readiness.spec.ts',
       'tests/e2e/ssh-terminal-window-wake-stale-grid-repro.spec.ts'
     ],
+    // Why the store/startup/shared additions: the SSH-named authorities stop at the main
+    // process and the pane component, but the reconnect ledgers and retained-payload
+    // admission that decide whether a pane rebinds live in the renderer store.
     matches: (file) =>
       isProductSource(file) &&
-      /^(?:src\/main\/ssh\/|src\/main\/providers\/ssh-|src\/main\/ipc\/(?:ssh-|pty)|src\/relay\/|src\/renderer\/src\/components\/terminal-pane\/(?:pty-|ssh-|remote-runtime-|terminal-parked-pty))/.test(
+      /^(?:src\/main\/ssh\/|src\/main\/providers\/ssh-|src\/main\/ipc\/(?:ssh-|pty)|src\/main\/runtime\/(?:public-ssh-state|ssh-file-explorer-chunk-read)\.ts|src\/relay\/|src\/shared\/(?:ssh-|skill-ssh-relay-contract)|src\/renderer\/src\/startup\/(?:ssh-startup-reconnect|startup-ssh-connection-restore)\.ts|src\/renderer\/src\/store\/slices\/(?:ssh|direct-ssh-)|src\/renderer\/src\/components\/terminal-pane\/(?:pty-|ssh-|remote-runtime-|terminal-parked-pty))/.test(
+        file
+      )
+  },
+  {
+    // Why a sibling route rather than more paths on ssh-terminal-source: these modules carry
+    // no "ssh" in their names, and only the two restore specs gate them. Folding them in
+    // would run the whole SSH terminal list for a tab-tombstone edit.
+    id: 'ssh-workspace-session-restore',
+    specs: [
+      'tests/e2e/ssh-cold-activation-restore.spec.ts',
+      'tests/e2e/ssh-reconnect-tab-destruction.spec.ts'
+    ],
+    matches: (file) =>
+      isProductSource(file) &&
+      /^(?:src\/main\/ipc\/remote-workspace|src\/shared\/remote-workspace-|src\/renderer\/src\/hooks\/remote-workspace-|src\/renderer\/src\/lib\/worktree-(?:initial-terminal-seeding|default-terminal-tabs)\.ts|src\/renderer\/src\/components\/terminal\/initial-terminal)/.test(
         file
       )
   },
@@ -131,6 +151,18 @@ export function selectPrE2eSpecs(changedPaths, reportRoute = () => undefined) {
   return [...specs].sort((left, right) => left.localeCompare(right))
 }
 
+/** Routes whose authorities are SSH execution source, and so require the Docker-SSH lane. */
+export const SSH_SOURCE_ROUTE_IDS = ['ssh-terminal-source', 'ssh-workspace-session-restore']
+
+// Why derive this from the routes instead of a second path list: the Docker-SSH lane used to
+// trigger only because one route happened to list a startup-readiness spec, so pruning that
+// spec would have silently retired the lane. Two lists that must agree is how that drifted.
+export function hasSshSourceChange(changedPaths) {
+  return PR_E2E_SOURCE_ROUTES.filter((route) => SSH_SOURCE_ROUTE_IDS.includes(route.id)).some(
+    (route) => changedPaths.some(route.matches)
+  )
+}
+
 if (process.argv[1] && import.meta.url === pathToFileURL(process.argv[1]).href) {
   let input = ''
   process.stdin.setEncoding('utf8')
@@ -138,6 +170,10 @@ if (process.argv[1] && import.meta.url === pathToFileURL(process.argv[1]).href)
     input += chunk
   }
   const changedPaths = input.split(/\r?\n/).filter(Boolean)
-  const specs = selectPrE2eSpecs(changedPaths, (message) => console.error(message))
-  process.stdout.write(`${JSON.stringify(specs)}\n`)
+  if (process.argv.includes('--ssh-source')) {
+    process.stdout.write(`${hasSshSourceChange(changedPaths)}\n`)
+  } else {
+    const specs = selectPrE2eSpecs(changedPaths, (message) => console.error(message))
+    process.stdout.write(`${JSON.stringify(specs)}\n`)
+  }
 }
diff --git a/config/scripts/run-ssh-docker-e2e.mjs b/config/scripts/run-ssh-docker-e2e.mjs
new file mode 100644
index 00000000000..8000c8a0c26
--- /dev/null
+++ b/config/scripts/run-ssh-docker-e2e.mjs
@@ -0,0 +1,93 @@
+import { spawnSync } from 'node:child_process'
+
+const rawExtraArgs = process.argv.slice(2)
+const extraArgs = rawExtraArgs[0] === '--' ? rawExtraArgs.slice(1) : rawExtraArgs
+const pnpm = process.platform === 'win32' ? 'pnpm.cmd' : 'pnpm'
+const env = {
+  ...process.env,
+  ORCA_E2E_SSH_DOCKER: '1',
+  ORCA_E2E_WEB_CLIENT: '1'
+}
+
+// Why: Node's CVE-2024-27980 hardening rejects .cmd spawns without shell on Windows.
+const spawnOptions = {
+  stdio: 'inherit',
+  env,
+  shell: process.platform === 'win32'
+}
+
+const runtime = spawnSync(pnpm, ['run', 'ensure:electron-runtime'], spawnOptions)
+
+if (runtime.status !== 0) {
+  process.exit(runtime.status ?? 1)
+}
+
+// Why one explicit list: these specs self-skip without ORCA_E2E_SSH_DOCKER and no sharded lane
+// sets it, so a spec in no runner runs nowhere. The gate contract proves every flag-reading
+// spec is claimed here, by the watcher-isolation or parking runner, or by a listed exclusion.
+//
+// Deliberately absent, and therefore still covered by no CI trigger:
+//   ssh-docker-relay-perf.spec.ts — wall-clock latency thresholds; flaky budgets here would
+//     cost the lane its credibility. NOTE: a runner script test:e2e:ssh-docker-perf exists in
+//     package.json but NO workflow invokes it, so this spec currently runs in no CI lane at
+//     all. Recorded as a real gap, not as coverage living somewhere else.
+//   ssh-codex-display-artifacts-repro.spec.ts — installs a real remote codex binary that CI
+//     runners do not have (observed as `spawn codex ENOENT`). Runs in no CI lane at all.
+//   ssh-docker-bulk-open-freeze-repro.spec.ts — two reasons, both disqualifying:
+//     (a) it is a perf oracle, not a correctness one: SOFT_FREEZE_LAG_MS=2500 /
+//         HARD_FREEZE_LAG_MS=5000 measured by a renderer lag probe under a deliberate
+//         5-pane output flood on a 420s budget. Same rule as ssh-docker-relay-perf above.
+//     (b) it is ROTTED: four call sites are out of date against terminal.ts's current
+//         helpers — execInTerminal gained a ptyId parameter and splitActiveTerminalPane
+//         gained a direction, so it cannot compile, let alone pass. Repairing it needs two
+//         semantic decisions (which ptyId to capture, which split direction) that change
+//         what the repro measures. Tracked in stablyai/orca#16764.
+//
+// Why both projects: ssh-port-forward-lifecycle is @headful, which the headless project
+// grep-inverts away.
+//
+// Known gaps in SSH e2e coverage, recorded here because nothing else names them:
+//   - The job that runs this is still called `ssh-docker-watcher-isolation`, though watcher
+//     isolation is now one spec of many. Renaming it changes the GitHub check name and can
+//     break required-check config, so the name understates the job on purpose.
+//   - E2E does not gate merges: `verify.needs` in pr.yml omits `e2e` while the suite is red on
+//     main. Nothing in this lane blocks a PR yet. pr.yml's Require-successful-checks comment
+//     has the exact wiring to flip it, and the gate contract asserts the current state.
+//   - Five specs and one unit test are gated on env vars no workflow sets, so they run nowhere
+//     and are not Docker-gated, which puts them outside this file's contract:
+//       local-ssh-browser-routing (ORCA_E2E_LOCAL_SSH_BROWSER)
+//       ssh-client-hosted-browser-drop-reconnect (ORCA_E2E_SSH_CLIENT_HOSTED_BROWSER)
+//       nested-runtime-ssh-lifecycle, nested-runtime-ssh-routing (ORCA_E2E_NESTED_RUNTIME_SSH)
+//       ssh-localhost (ORCA_E2E_SSH_LOCALHOST)
+//       ssh-browser-network-execution-route.docker.unit.test.ts (ORCA_RUN_DOCKER_SSH_BROWSER_E2E)
+//     Runner scripts for the first four sit unused in package.json; no workflow calls them.
+const result = spawnSync(
+  pnpm,
+  [
+    'exec',
+    'playwright',
+    'test',
+    'tests/e2e/pty-input-write-queue-ssh.spec.ts',
+    'tests/e2e/ssh-ai-vault-session-history.spec.ts',
+    'tests/e2e/ssh-cold-activation-restore.spec.ts',
+    'tests/e2e/ssh-docker-reconnect-pane-restore.spec.ts',
+    'tests/e2e/ssh-external-image-preview.spec.ts',
+    'tests/e2e/ssh-pi-compatible-agent-title.spec.ts',
+    'tests/e2e/ssh-port-forward-lifecycle.spec.ts',
+    'tests/e2e/ssh-reconnect-tab-destruction.spec.ts',
+    'tests/e2e/ssh-restart-tab-accumulation.spec.ts',
+    'tests/e2e/ssh-skill-installation.spec.ts',
+    'tests/e2e/ssh-terminal-window-wake-stale-grid-repro.spec.ts',
+    '--config',
+    'tests/playwright.config.ts',
+    '--project',
+    'electron-headless',
+    '--project',
+    'electron-headful',
+    '--workers=1',
+    ...extraArgs
+  ],
+  spawnOptions
+)
+
+process.exit(result.status ?? 1)
diff --git a/package.json b/package.json
index 7b46b369406..c8e59299c70 100644
--- a/package.json
+++ b/package.json
@@ -111,6 +111,7 @@
     "test:e2e:terminal-perf:html-report": "node config/scripts/generate-terminal-perf-html-report.mjs",
     "test:e2e:ssh-docker-perf": "node config/scripts/run-ssh-docker-perf-e2e.mjs",
     "test:e2e:ssh-docker-watcher-isolation": "node config/scripts/run-ssh-docker-watcher-isolation-e2e.mjs",
+    "test:e2e:ssh-docker": "node config/scripts/run-ssh-docker-e2e.mjs",
     "test:e2e:ssh-client-hosted-browser": "node config/scripts/run-ssh-client-hosted-browser-drop-reconnect-e2e.mjs",
     "test:e2e:local-ssh-browser": "node config/scripts/run-local-ssh-browser-routing-e2e.mjs",
     "test:e2e:ssh-docker-terminal-parking": "node config/scripts/run-ssh-docker-terminal-parking-e2e.mjs",
diff --git a/src/main/ipc/remote-workspace-snapshot-normalization.test.ts b/src/main/ipc/remote-workspace-snapshot-normalization.test.ts
new file mode 100644
index 00000000000..7f57b432813
--- /dev/null
+++ b/src/main/ipc/remote-workspace-snapshot-normalization.test.ts
@@ -0,0 +1,88 @@
+import { describe, expect, it } from 'vitest'
+
+import {
+  normalizeSnapshot,
+  remoteWorkspaceSessionMatchesSnapshot
+} from './remote-workspace-snapshot-normalization'
+import type {
+  RemoteWorkspaceSession,
+  RemoteWorkspaceSnapshot
+} from '../../shared/remote-workspace-types'
+
+function session(overrides: Partial<RemoteWorkspaceSession> = {}): RemoteWorkspaceSession {
+  return {
+    activeWorktreePath: null,
+    activeTabId: null,
+    tabsByWorktreePath: {},
+    terminalLayoutsByTabId: {},
+    ...overrides
+  }
+}
+
+function snapshotOf(session: RemoteWorkspaceSession): RemoteWorkspaceSnapshot {
+  return { namespace: 'ns', revision: 3, updatedAt: 1, schemaVersion: 1, session }
+}
+
+/**
+ * Every declared field, each holding a value the normalizer must neither drop nor flatten.
+ *
+ * `Required` is the ratchet: normalizeRemoteSession rebuilds the session as an object literal, so a
+ * field added to the wire type and forgotten there is invisible — it round-trips through the
+ * projection, reaches the relay, and is stripped on the way back. Declaring the fixture Required
+ * makes the next such field a compile error here before it can become a silent data loss.
+ */
+const everyDeclaredField: Required<RemoteWorkspaceSession> = {
+  activeWorktreePath: '/repo',
+  activeTabId: 'tab-1',
+  tabsByWorktreePath: { '/repo': [{ id: 'tab-1', type: 'terminal', title: 'Shell' } as never] },
+  terminalLayoutsByTabId: { 'tab-1': { kind: 'leaf', ptyId: 'pty-1' } as never },
+  activeWorktreePathsOnShutdown: ['/repo'],
+  activeTabIdByWorktreePath: { '/repo': 'tab-1' },
+  remoteSessionIdsByTabId: { 'tab-1': 'session-1' },
+  lastVisitedAtByWorktreePath: { '/repo': 42 },
+  defaultTerminalTabsAppliedByWorktreePath: { '/repo': true }
+}
+
+describe('normalizeSnapshot: field coverage', () => {
+  it('copies every declared field of the wire session', () => {
+    const normalized = normalizeSnapshot(snapshotOf(everyDeclaredField), 'ns').session
+
+    expect(Object.keys(normalized).sort()).toEqual(Object.keys(everyDeclaredField).sort())
+    expect(normalized).toEqual(everyDeclaredField)
+  })
+})
+
+describe('normalizeSnapshot: defaultTerminalTabsAppliedByWorktreePath', () => {
+  it('carries the marker through instead of dropping it', () => {
+    // The renderer exports this field and its importer reads it, but the normalizer every read
+    // passes through never copied it — so the flag reached the relay and could never come back.
+    const raw = snapshotOf(session({ defaultTerminalTabsAppliedByWorktreePath: { '/repo': true } }))
+
+    expect(normalizeSnapshot(raw, 'ns').session.defaultTerminalTabsAppliedByWorktreePath).toEqual({
+      '/repo': true
+    })
+  })
+
+  it('treats an empty marker record as absent, like every other optional record', () => {
+    // The export always emits an object, so {} and absent both mean "no worktree has applied
+    // them". Collapsing them keeps a no-op export from looking like a change to the patch guard.
+    const raw = snapshotOf(session({ defaultTerminalTabsAppliedByWorktreePath: {} }))
+
+    expect(
+      normalizeSnapshot(raw, 'ns').session.defaultTerminalTabsAppliedByWorktreePath
+    ).toBeUndefined()
+  })
+})
+
+describe('remoteWorkspaceSessionMatchesSnapshot', () => {
+  it('sees a change that only sets the default-terminal-tabs marker', () => {
+    // patchRemoteWorkspaceSession short-circuits on this comparison, so a field it cannot see is a
+    // field that can never be written at all.
+    expect(
+      remoteWorkspaceSessionMatchesSnapshot(
+        snapshotOf(session()),
+        session({ defaultTerminalTabsAppliedByWorktreePath: { '/repo': true } })
+      )
+    ).toBe(false)
+  })
+})
diff --git a/src/main/ipc/remote-workspace-snapshot-normalization.ts b/src/main/ipc/remote-workspace-snapshot-normalization.ts
index 1d24063ec4d..749d83cc066 100644
--- a/src/main/ipc/remote-workspace-snapshot-normalization.ts
+++ b/src/main/ipc/remote-workspace-snapshot-normalization.ts
@@ -62,6 +62,11 @@ function normalizeRemoteSession(raw: unknown): RemoteWorkspaceSession {
     ),
     lastVisitedAtByWorktreePath: normalizeOptionalRecord<Record<string, number>>(
       input.lastVisitedAtByWorktreePath
+    ),
+    // Dropping this made the field write-only: every read stripped it, and the patch guard below
+    // compares normalized sessions, so a change that only sets it looked like no change at all.
+    defaultTerminalTabsAppliedByWorktreePath: normalizeOptionalRecord<Record<string, true>>(
+      input.defaultTerminalTabsAppliedByWorktreePath
     )
   }
 }
diff --git a/src/main/ipc/worktree-create-lineage.test.ts b/src/main/ipc/worktree-create-lineage.test.ts
new file mode 100644
index 00000000000..fa7e101ac3f
--- /dev/null
+++ b/src/main/ipc/worktree-create-lineage.test.ts
@@ -0,0 +1,265 @@
+import { afterEach, beforeEach, describe, expect, it, vi } from 'vitest'
+import type { CreateWorktreeArgs } from '../../shared/worktree/create-types'
+import type { WorktreeMeta } from '../../shared/worktree/meta-types'
+import type { Worktree } from '../../shared/worktree/types'
+import { folderWorkspaceKey, worktreeWorkspaceKey } from '../../shared/workspace-scope'
+import {
+  assertAttachableParentWorkspace,
+  recordWorkspaceLineageForCreatedWorktree
+} from './worktree-remote'
+
+const CHILD_ID = 'repo-1::/repos/child'
+const PARENT_ID = 'repo-1::/repos/parent'
+const CREATED_AT = 1_700_000_000_000
+
+function createdWorktree(overrides: Partial<Worktree> = {}): Worktree {
+  return {
+    id: CHILD_ID,
+    instanceId: 'child-instance',
+    repoId: 'repo-1',
+    hostId: 'local',
+    projectId: 'project-1',
+    path: '/repos/child',
+    head: 'abc123',
+    branch: 'refs/heads/child',
+    isBare: false,
+    isMainWorktree: false,
+    displayName: 'child',
+    comment: '',
+    linkedIssue: null,
+    linkedPR: null,
+    linkedLinearIssue: null,
+    isArchived: false,
+    isUnread: false,
+    isPinned: false,
+    sortOrder: 0,
+    lastActivityAt: 0,
+    ...overrides
+  }
+}
+
+function parentMeta(overrides: Partial<WorktreeMeta> = {}): WorktreeMeta {
+  return {
+    instanceId: 'parent-instance',
+    hostId: 'local',
+    projectId: 'project-1',
+    displayName: 'parent',
+    comment: '',
+    linkedIssue: null,
+    linkedPR: null,
+    linkedLinearIssue: null,
+    isArchived: false,
+    isUnread: false,
+    isPinned: false,
+    sortOrder: 0,
+    lastActivityAt: 0,
+    ...overrides
+  }
+}
+
+function createStore(options: {
+  metaById?: Record<string, WorktreeMeta>
+  folderWorkspaceIds?: string[]
+}) {
+  const metaById = options.metaById ?? {}
+  const folderWorkspaceIds = new Set(options.folderWorkspaceIds ?? [])
+  return {
+    getWorktreeMeta: vi.fn((id: string) => metaById[id]),
+    getFolderWorkspace: vi.fn((id: string) =>
+      folderWorkspaceIds.has(id) ? { id, path: `/folders/${id}` } : undefined
+    ),
+    setWorktreeLineage: vi.fn((_id: string, lineage: unknown) => lineage),
+    setWorkspaceLineage: vi.fn((lineage: unknown) => lineage)
+  }
+}
+
+function record(
+  store: ReturnType<typeof createStore>,
+  args: Partial<CreateWorktreeArgs>,
+  worktree = createdWorktree()
+) {
+  return recordWorkspaceLineageForCreatedWorktree(
+    store as never,
+    args as CreateWorktreeArgs,
+    worktree,
+    CREATED_AT
+  )
+}
+
+describe('recordWorkspaceLineageForCreatedWorktree', () => {
+  beforeEach(() => {
+    vi.spyOn(console, 'warn').mockImplementation(() => {})
+  })
+
+  afterEach(() => {
+    vi.restoreAllMocks()
+  })
+
+  it('writes both lineage rows for a worktree parent inside the same repo/host/project', () => {
+    const store = createStore({ metaById: { [PARENT_ID]: parentMeta() } })
+
+    const result = record(store, { parentWorkspace: worktreeWorkspaceKey(PARENT_ID) })
+
+    expect(store.setWorktreeLineage).toHaveBeenCalledWith(CHILD_ID, {
+      worktreeId: CHILD_ID,
+      worktreeInstanceId: 'child-instance',
+      parentWorktreeId: PARENT_ID,
+      parentWorktreeInstanceId: 'parent-instance',
+      origin: 'manual',
+      capture: { source: 'manual-action', confidence: 'explicit' },
+      createdAt: CREATED_AT
+    })
+    expect(result.lineage).toMatchObject({
+      parentWorktreeId: PARENT_ID,
+      parentWorktreeInstanceId: 'parent-instance',
+      origin: 'manual',
+      capture: { source: 'manual-action', confidence: 'explicit' }
+    })
+    expect(result.workspaceLineage).toEqual({
+      childWorkspaceKey: worktreeWorkspaceKey(CHILD_ID),
+      childInstanceId: 'child-instance',
+      parentWorkspaceKey: worktreeWorkspaceKey(PARENT_ID),
+      parentInstanceId: 'parent-instance',
+      origin: 'manual',
+      capture: { source: 'manual-action', confidence: 'explicit' },
+      createdAt: CREATED_AT
+    })
+  })
+
+  it('skips both lineage records when the parent belongs to a different repo', () => {
+    const foreignParentId = 'repo-2::/repos/parent'
+    const store = createStore({ metaById: { [foreignParentId]: parentMeta() } })
+
+    const result = record(store, { parentWorkspace: worktreeWorkspaceKey(foreignParentId) })
+
+    expect(store.setWorktreeLineage).not.toHaveBeenCalled()
+    expect(result.lineage).toBeNull()
+    expect(store.setWorkspaceLineage).not.toHaveBeenCalled()
+    expect(result.workspaceLineage).toBeNull()
+  })
+
+  it.each([
+    ['host', parentMeta({ hostId: 'ssh:other-host' })],
+    ['project', parentMeta({ projectId: 'project-2' })]
+  ])(
+    'skips both lineage records when the parent %s conflicts, so no cross-host row is persisted',
+    (_label, meta) => {
+      const store = createStore({ metaById: { [PARENT_ID]: meta } })
+
+      const result = record(store, { parentWorkspace: worktreeWorkspaceKey(PARENT_ID) })
+
+      expect(store.setWorktreeLineage).not.toHaveBeenCalled()
+      expect(result.lineage).toBeNull()
+      // A persisted cross-host row makes filterLineageForHost return null for the entire host.
+      expect(store.setWorkspaceLineage).not.toHaveBeenCalled()
+      expect(result.workspaceLineage).toBeNull()
+    }
+  )
+
+  it('skips worktree lineage when the parent has no instance identity', () => {
+    const store = createStore({ metaById: { [PARENT_ID]: parentMeta({ instanceId: undefined }) } })
+
+    const result = record(store, { parentWorkspace: worktreeWorkspaceKey(PARENT_ID) })
+
+    expect(store.setWorktreeLineage).not.toHaveBeenCalled()
+    expect(result.lineage).toBeNull()
+    expect(result.workspaceLineage).toMatchObject({
+      parentWorkspaceKey: worktreeWorkspaceKey(PARENT_ID),
+      parentInstanceId: null
+    })
+  })
+
+  it('records only workspace lineage for a folder-workspace parent', () => {
+    const store = createStore({ folderWorkspaceIds: ['folder-1'] })
+
+    const result = record(store, { parentWorkspace: folderWorkspaceKey('folder-1') })
+
+    expect(store.setWorktreeLineage).not.toHaveBeenCalled()
+    expect(result.lineage).toBeNull()
+    expect(result.workspaceLineage).toMatchObject({
+      parentWorkspaceKey: folderWorkspaceKey('folder-1'),
+      parentInstanceId: null,
+      capture: { source: 'active-workspace', confidence: 'explicit' }
+    })
+  })
+
+  it('records nothing without a parent workspace', () => {
+    const store = createStore({})
+
+    const result = record(store, {})
+
+    expect(store.setWorktreeLineage).not.toHaveBeenCalled()
+    expect(store.setWorkspaceLineage).not.toHaveBeenCalled()
+    expect(result).toEqual({ lineage: null, workspaceLineage: null })
+  })
+
+  it('records nothing when the parent workspace is the created worktree itself', () => {
+    const store = createStore({ metaById: { [CHILD_ID]: parentMeta() } })
+
+    const result = record(store, { parentWorkspace: worktreeWorkspaceKey(CHILD_ID) })
+
+    expect(store.setWorktreeLineage).not.toHaveBeenCalled()
+    expect(store.setWorkspaceLineage).not.toHaveBeenCalled()
+    expect(result).toEqual({ lineage: null, workspaceLineage: null })
+  })
+
+  it('records nothing when the parent worktree disappeared before the write', () => {
+    const store = createStore({})
+
+    const result = record(store, { parentWorkspace: worktreeWorkspaceKey(PARENT_ID) })
+
+    expect(store.setWorkspaceLineage).not.toHaveBeenCalled()
+    expect(result).toEqual({ lineage: null, workspaceLineage: null })
+  })
+})
+
+describe('assertAttachableParentWorkspace', () => {
+  const childKey = worktreeWorkspaceKey(CHILD_ID)
+
+  beforeEach(() => {
+    vi.spyOn(console, 'warn').mockImplementation(() => {})
+  })
+
+  afterEach(() => {
+    vi.restoreAllMocks()
+  })
+
+  function assertParent(
+    store: ReturnType<typeof createStore>,
+    parentWorkspace: CreateWorktreeArgs['parentWorkspace']
+  ) {
+    assertAttachableParentWorkspace(store as never, parentWorkspace, childKey)
+  }
+
+  // Why: the pick can go stale between the composer and the create; nesting is decoration, not the job.
+  it.each([
+    ['worktree', () => worktreeWorkspaceKey(PARENT_ID)],
+    ['folder', () => folderWorkspaceKey('folder-gone')]
+  ])('degrades instead of failing when the %s parent disappeared', (_label, key) => {
+    const store = createStore({})
+
+    expect(() => assertParent(store, key())).not.toThrow()
+    expect(console.warn).toHaveBeenCalled()
+  })
+
+  it('accepts a parent that still exists', () => {
+    const store = createStore({ metaById: { [PARENT_ID]: parentMeta() } })
+
+    expect(() => assertParent(store, worktreeWorkspaceKey(PARENT_ID))).not.toThrow()
+    expect(console.warn).not.toHaveBeenCalled()
+  })
+
+  it('rejects a self-referential parent', () => {
+    const store = createStore({ metaById: { [CHILD_ID]: parentMeta() } })
+
+    expect(() => assertParent(store, childKey)).toThrow(/cannot be attached to itself/)
+  })
+
+  it('rejects a malformed parent key', () => {
+    const store = createStore({})
+
+    expect(() => assertParent(store, 'not-a-workspace-key' as never)).toThrow(
+      /Invalid parent workspace/
+    )
+  })
+})
diff --git a/src/main/ipc/worktree-remote.ts b/src/main/ipc/worktree-remote.ts
index c20899ea9cf..977c29d8792 100644
--- a/src/main/ipc/worktree-remote.ts
+++ b/src/main/ipc/worktree-remote.ts
@@ -91,6 +91,7 @@ import { findCreatedWorktree } from './created-worktree-reconciliation'
 import type { BranchPrefixSettings } from '../../shared/branch-prefix'
 import { getRepoIdFromWorktreeId } from '../../shared/worktree/id'
 import { parseWorkspaceKey, worktreeWorkspaceKey } from '../../shared/workspace-scope'
+import { sharesWorktreeLineageBoundary } from '../../shared/resolved-worktree-lineage'
 import {
   cleanupUnusedWorktreePushTargetRemoteWithExec,
   sameGitHubRemoteUrl,
@@ -197,7 +198,11 @@ function getSetupRunnerCommandPlatformForLaunch(
   return getSetupRunnerCommandPlatformForPath(setup?.runnerScriptPath ?? '', fallbackPlatform)
 }
 
-function validateWorkspaceLineageParentBeforeCreate(
+/** Why not throw on a missing parent: nesting is optional decoration, and the pick can go stale
+ *  between the composer and the create. A malformed or self-referential key is a bad request and
+ *  still fails; a parent that simply disappeared degrades to an unattached workspace, matching the
+ *  runtime path and `recordWorkspaceLineageForCreatedWorktree`. */
+export function assertAttachableParentWorkspace(
   store: Store,
   parentWorkspace: CreateWorktreeArgs['parentWorkspace'],
   childWorkspaceKey: ReturnType<typeof worktreeWorkspaceKey>
@@ -213,51 +218,120 @@ function validateWorkspaceLineageParentBeforeCreate(
     throw new Error(`Invalid parent workspace: ${parentWorkspace}`)
   }
   if (parentScope.type === 'folder' && !store.getFolderWorkspace(parentScope.folderWorkspaceId)) {
-    throw new Error(`Parent folder workspace not found: ${parentWorkspace}`)
+    console.warn(`[worktree-create] parent folder workspace not found: ${parentWorkspace}`)
+    return
   }
   if (parentScope.type === 'worktree' && !store.getWorktreeMeta(parentScope.worktreeId)) {
-    throw new Error(`Parent worktree workspace not found: ${parentWorkspace}`)
+    console.warn(`[worktree-create] parent worktree workspace not found: ${parentWorkspace}`)
   }
 }
 
-function recordWorkspaceLineageForCreatedWorktree(
+type CreatedWorktreeLineageRecords = {
+  lineage: CreateWorktreeResult['lineage']
+  workspaceLineage: CreateWorktreeResult['workspaceLineage']
+}
+
+const NO_CREATED_WORKTREE_LINEAGE: CreatedWorktreeLineageRecords = {
+  lineage: null,
+  workspaceLineage: null
+}
+
+/** Mirrors the projection's edge rule so we never persist a row the sidebar would silently drop.
+ *  WorktreeMeta has no repoId, so the parent's comes from its `<repoId>::<path>` id. */
+function createdWorktreeSharesParentLineageBoundary(
+  worktree: Worktree,
+  parentWorktreeId: string,
+  parentMeta: WorktreeMeta
+): boolean {
+  return sharesWorktreeLineageBoundary(worktree, {
+    repoId: getRepoIdFromWorktreeId(parentWorktreeId),
+    hostId: parentMeta.hostId,
+    projectId: parentMeta.projectId
+  })
+}
+
+export function recordWorkspaceLineageForCreatedWorktree(
   store: Store,
   args: CreateWorktreeArgs,
   worktree: Worktree,
   createdAt: number
-): CreateWorktreeResult['workspaceLineage'] {
+): CreatedWorktreeLineageRecords {
   if (!args.parentWorkspace || !worktree.instanceId) {
-    return null
+    return NO_CREATED_WORKTREE_LINEAGE
   }
   const childWorkspaceKey = worktreeWorkspaceKey(worktree.id)
   if (args.parentWorkspace === childWorkspaceKey) {
     console.warn(`[worktree-create] refusing to attach ${worktree.id} to itself`)
-    return null
+    return NO_CREATED_WORKTREE_LINEAGE
   }
   const parentScope = parseWorkspaceKey(args.parentWorkspace)
   if (!parentScope) {
     console.warn(`[worktree-create] ignoring invalid parent workspace ${args.parentWorkspace}`)
-    return null
+    return NO_CREATED_WORKTREE_LINEAGE
   }
   if (parentScope.type === 'folder' && !store.getFolderWorkspace(parentScope.folderWorkspaceId)) {
     console.warn(`[worktree-create] parent folder workspace disappeared: ${args.parentWorkspace}`)
-    return null
+    return NO_CREATED_WORKTREE_LINEAGE
   }
   const parentWorktreeMeta =
     parentScope.type === 'worktree' ? store.getWorktreeMeta(parentScope.worktreeId) : null
   if (parentScope.type === 'worktree' && !parentWorktreeMeta) {
     console.warn(`[worktree-create] parent worktree workspace disappeared: ${args.parentWorkspace}`)
-    return null
+    return NO_CREATED_WORKTREE_LINEAGE
   }
-  return store.setWorkspaceLineage({
+
+  // Why: only a worktree parent produces sidebar nesting; a folder parent has no WorktreeLineage row.
+  let lineage: CreateWorktreeResult['lineage'] = null
+  let parentOutsideLineageBoundary = false
+  if (parentScope.type === 'worktree' && parentWorktreeMeta) {
+    if (!parentWorktreeMeta.instanceId) {
+      console.warn(
+        `[worktree-create] parent ${parentScope.worktreeId} has no instance identity; skipping lineage`
+      )
+    } else if (
+      !createdWorktreeSharesParentLineageBoundary(
+        worktree,
+        parentScope.worktreeId,
+        parentWorktreeMeta
+      )
+    ) {
+      parentOutsideLineageBoundary = true
+      console.warn(
+        `[worktree-create] parent ${parentScope.worktreeId} is outside ${worktree.id}'s repo/host/project boundary; skipping lineage`
+      )
+    } else {
+      lineage = store.setWorktreeLineage(worktree.id, {
+        worktreeId: worktree.id,
+        worktreeInstanceId: worktree.instanceId,
+        parentWorktreeId: parentScope.worktreeId,
+        parentWorktreeInstanceId: parentWorktreeMeta.instanceId,
+        origin: 'manual',
+        capture: { source: 'manual-action', confidence: 'explicit' },
+        createdAt
+      })
+    }
+  }
+
+  // Why: persisting a workspace row for an out-of-boundary worktree parent poisons the whole host —
+  // `filterLineageForHost` returns null for any owned row whose child and parent hosts differ, so
+  // every nesting on that host stops hydrating, and the row survives restarts.
+  if (parentOutsideLineageBoundary) {
+    return NO_CREATED_WORKTREE_LINEAGE
+  }
+
+  const workspaceLineage = store.setWorkspaceLineage({
     childWorkspaceKey,
     childInstanceId: worktree.instanceId,
     parentWorkspaceKey: args.parentWorkspace,
     parentInstanceId: parentWorktreeMeta?.instanceId ?? null,
     origin: 'manual',
-    capture: { source: 'active-workspace', confidence: 'explicit' },
+    capture: {
+      source: parentScope.type === 'worktree' ? 'manual-action' : 'active-workspace',
+      confidence: 'explicit'
+    },
     createdAt
   })
+  return { lineage, workspaceLineage }
 }
 
 function countNonEmptyGitOutputLines(output: string): number {
@@ -1677,7 +1751,7 @@ export async function createRemoteWorktree(
     )
   }
 
-  validateWorkspaceLineageParentBeforeCreate(
+  assertAttachableParentWorkspace(
     store,
     args.parentWorkspace,
     worktreeWorkspaceKey(`${repo.id}::${remotePath}`)
@@ -1915,7 +1989,12 @@ export async function createRemoteWorktree(
     const meta = store.setWorktreeMeta(worktreeId, metaUpdates)
     return { worktree: mergeWorktree(repo.id, created, meta) }
   })
-  const workspaceLineage = recordWorkspaceLineageForCreatedWorktree(store, args, worktree, now)
+  const { lineage: worktreeLineage, workspaceLineage } = recordWorkspaceLineageForCreatedWorktree(
+    store,
+    args,
+    worktree,
+    now
+  )
 
   // Why: shared/symlink paths, `orca.yaml` shared directories, and `.worktreeinclude` copies are local-only; remote (SSH) support needs a new relay method + auth surface, so all are skipped here.
 
@@ -1962,7 +2041,14 @@ export async function createRemoteWorktree(
 
   notifyWorktreesChanged(mainWindow, repo.id)
   return {
-    worktree: { ...worktree, workspaceLineage },
+    worktree: {
+      ...worktree,
+      workspaceLineage,
+      ...(worktreeLineage
+        ? { lineage: worktreeLineage, parentWorktreeId: worktreeLineage.parentWorktreeId }
+        : {})
+    },
+    ...(worktreeLineage ? { lineage: worktreeLineage } : {}),
     ...(workspaceLineage ? { workspaceLineage } : {}),
     ...(setup ? { setup } : {}),
     ...(defaultTabs ? { defaultTabs } : {}),
@@ -2308,7 +2394,7 @@ export async function createLocalWorktree(
     )
   }
 
-  validateWorkspaceLineageParentBeforeCreate(
+  assertAttachableParentWorkspace(
     store,
     args.parentWorkspace,
     worktreeWorkspaceKey(`${repo.id}::${worktreePath}`)
@@ -2555,7 +2641,12 @@ export async function createLocalWorktree(
     const meta = store.setWorktreeMeta(worktreeId, metaUpdates)
     return { worktree: mergeWorktree(repo.id, created, meta) }
   })
-  const workspaceLineage = recordWorkspaceLineageForCreatedWorktree(store, args, worktree, now)
+  const { lineage: worktreeLineage, workspaceLineage } = recordWorkspaceLineageForCreatedWorktree(
+    store,
+    args,
+    worktree,
+    now
+  )
   // Why: reuse the roots creation already paid for via `git worktree list` so later IPC doesn't lazily rescan and trip macOS privacy prompts.
   registerWorktreeRootsForRepo(store, repo.id, [
     repo.path,
@@ -2658,7 +2749,14 @@ export async function createLocalWorktree(
 
   notifyWorktreesChanged(mainWindow, repo.id)
   return {
-    worktree: { ...worktree, workspaceLineage },
+    worktree: {
+      ...worktree,
+      workspaceLineage,
+      ...(worktreeLineage
+        ? { lineage: worktreeLineage, parentWorktreeId: worktreeLineage.parentWorktreeId }
+        : {})
+    },
+    ...(worktreeLineage ? { lineage: worktreeLineage } : {}),
     ...(workspaceLineage ? { workspaceLineage } : {}),
     ...(stagedStartup.activationSetup
       ? { setup: stagedStartup.activationSetup }
diff --git a/src/main/runtime/orca-runtime.test.ts b/src/main/runtime/orca-runtime.test.ts
index 7747797de4f..4f02816f1c5 100644
--- a/src/main/runtime/orca-runtime.test.ts
+++ b/src/main/runtime/orca-runtime.test.ts
@@ -6469,6 +6469,52 @@ describe('OrcaRuntimeService', () => {
     }
   })
 
+  // Why: the desktop composer sends `parentWorkspace` too, and a bare selector defaults to CLI
+  // provenance — the same user action must not carry different cleanup semantics per host.
+  it('records an app-selected parent workspace as a manual action', async () => {
+    vi.mocked(addWorktree).mockClear()
+    const created = {
+      path: '/tmp/workspaces/manual-child',
+      head: 'def',
+      branch: 'refs/heads/manual-child',
+      isBare: false,
+      isMainWorktree: false
+    }
+    const childId = `${TEST_REPO_ID}::${created.path}`
+    const metaById: Record<string, WorktreeMeta> = {}
+    const runtimeStore = {
+      ...createFolderWorkspaceRuntimeStore(),
+      getAllWorktreeMeta: () => metaById,
+      getWorktreeMeta: (worktreeId: string) => metaById[worktreeId],
+      setWorktreeMeta: (worktreeId: string, meta: Partial<WorktreeMeta>) => {
+        metaById[worktreeId] = { ...(metaById[worktreeId] ?? makeWorktreeMeta()), ...meta }
+        return metaById[worktreeId]
+      },
+      setWorkspaceLineage: vi.fn((lineage: WorkspaceLineage) => lineage)
+    }
+    computeWorktreePathMock.mockReturnValue(created.path)
+    ensurePathWithinWorkspaceMock.mockImplementation((pathValue: string) => pathValue)
+    vi.mocked(listWorktrees).mockResolvedValueOnce([created])
+    const runtime = new OrcaRuntimeService(runtimeStore as never)
+
+    const result = await runtime.createManagedWorktree({
+      repoSelector: TEST_REPO_ID,
+      name: 'manual-child',
+      baseBranch: 'origin/main',
+      lineage: {
+        parentWorkspace: TEST_FOLDER_WORKSPACE_KEY,
+        parentWorkspaceOrigin: 'manual'
+      }
+    })
+
+    expect(result.workspaceLineage).toMatchObject({
+      childWorkspaceKey: `worktree:${childId}`,
+      parentWorkspaceKey: TEST_FOLDER_WORKSPACE_KEY,
+      origin: 'manual',
+      capture: { source: 'active-workspace', confidence: 'explicit' }
+    })
+  })
+
   it('records folder workspace lineage inferred from environment context', async () => {
     vi.mocked(addWorktree).mockClear()
     const created = {
diff --git a/src/main/runtime/orca-runtime.ts b/src/main/runtime/orca-runtime.ts
index c81ca03ed04..c800b861a42 100644
--- a/src/main/runtime/orca-runtime.ts
+++ b/src/main/runtime/orca-runtime.ts
@@ -2902,6 +2902,8 @@ type ResolvedTerminalWorkspaceLaunchTarget = {
 
 type WorktreeLineageInput = {
   parentWorkspace?: string
+  /** Set by in-app parent pickers so the row is not recorded as a CLI flag. */
+  parentWorkspaceOrigin?: 'manual'
   envParentWorkspace?: string
   parentWorktree?: string
   cwdParentWorktree?: string
@@ -32581,11 +32583,20 @@ export class OrcaRuntimeService {
 
     if (input.parentWorkspace) {
       try {
+        const parent = await this.resolveWorkspaceParentSelector(input.parentWorkspace)
+        // Why: a picker in the app must record the same provenance as a local create, or the same
+        // user action would carry different cleanup semantics depending on where the repo lives.
         return {
           kind: 'lineage',
-          parent: await this.resolveWorkspaceParentSelector(input.parentWorkspace),
-          origin: 'cli',
-          capture: { source: 'explicit-cli-flag', confidence: 'explicit' }
+          parent,
+          origin: input.parentWorkspaceOrigin === 'manual' ? 'manual' : 'cli',
+          capture:
+            input.parentWorkspaceOrigin === 'manual'
+              ? {
+                  source: parent.type === 'worktree' ? 'manual-action' : 'active-workspace',
+                  confidence: 'explicit'
+                }
+              : { source: 'explicit-cli-flag', confidence: 'explicit' }
         }
       } catch (err) {
         throw new RuntimeLineageError(
diff --git a/src/main/runtime/rpc/methods/worktree-create-args.test.ts b/src/main/runtime/rpc/methods/worktree-create-args.test.ts
index fa2b773560b..5a55d54460f 100644
--- a/src/main/runtime/rpc/methods/worktree-create-args.test.ts
+++ b/src/main/runtime/rpc/methods/worktree-create-args.test.ts
@@ -26,4 +26,19 @@ describe('buildManagedWorktreeCreateArgs', () => {
       nameWasGenerated: true
     })
   })
+
+  it('carries the parent-pick provenance only when the client marked it manual', () => {
+    // Why: older clients never send it, and those creates really are CLI-flag equivalents.
+    expect(
+      build({ repo: 'id:repo-1', name: 'child', parentWorkspace: 'folder:f1' }).lineage
+    ).not.toHaveProperty('parentWorkspaceOrigin')
+    expect(
+      build({
+        repo: 'id:repo-1',
+        name: 'child',
+        parentWorkspace: 'folder:f1',
+        parentWorkspaceOrigin: 'manual'
+      }).lineage
+    ).toMatchObject({ parentWorkspaceOrigin: 'manual' })
+  })
 })
diff --git a/src/main/runtime/rpc/methods/worktree-create-args.ts b/src/main/runtime/rpc/methods/worktree-create-args.ts
index 2b86b12ee05..ac674f08d61 100644
--- a/src/main/runtime/rpc/methods/worktree-create-args.ts
+++ b/src/main/runtime/rpc/methods/worktree-create-args.ts
@@ -80,6 +80,7 @@ export function buildManagedWorktreeCreateArgs(
     startupDraft: params.startupDraft,
     lineage: {
       parentWorkspace: params.parentWorkspace,
+      ...(params.parentWorkspaceOrigin ? { parentWorkspaceOrigin: 'manual' as const } : {}),
       envParentWorkspace: params.envParentWorkspace,
       parentWorktree: params.parentWorktree,
       ...(params.cwdParentWorktree ? { cwdParentWorktree: params.cwdParentWorktree } : {}),
diff --git a/src/main/runtime/rpc/methods/worktree-create-schemas.ts b/src/main/runtime/rpc/methods/worktree-create-schemas.ts
index 507f44b325b..e296b9c3ace 100644
--- a/src/main/runtime/rpc/methods/worktree-create-schemas.ts
+++ b/src/main/runtime/rpc/methods/worktree-create-schemas.ts
@@ -75,6 +75,9 @@ export const WorktreeCreate = z
     // startup and defaultTabs. Pass an explicit target to opt into an all-surface reveal.
     navigation: z.enum(RUNTIME_NAVIGATION_TARGETS).optional(),
     parentWorkspace: OptionalString,
+    // Why: an app-selected parent is a manual action, not the CLI's `--parent-workspace` flag.
+    // Absent keeps the CLI provenance older clients rely on.
+    parentWorkspaceOrigin: z.literal('manual').optional(),
     envParentWorkspace: OptionalString,
     parentWorktree: OptionalString,
     cwdParentWorktree: OptionalString,
diff --git a/src/renderer/src/assets/main.css b/src/renderer/src/assets/main.css
index 9d75836cd11..cd556d6f486 100644
--- a/src/renderer/src/assets/main.css
+++ b/src/renderer/src/assets/main.css
@@ -1145,9 +1145,11 @@ html.native-shell .app-layout {
 
 /* ── Jump palette (Cmd+J) ─────────────────────────────── */
 
-/* Why the data-slot qualifier: CommandItem also sets data-[selected=true]:bg-accent;
-   this selector must beat that utility so light-mode selection is actually visible. */
-[data-slot='command-item'].jump-palette-item[data-selected='true'] {
+/* Why the extra qualifier: CommandItem also sets data-[selected=true]:bg-accent;
+   this selector must beat that utility so light-mode selection is actually visible.
+   The role='option' arm covers virtualized rows that render outside cmdk. */
+[data-slot='command-item'].jump-palette-item[data-selected='true'],
+[role='option'].jump-palette-item[data-selected='true'] {
   /* Why: flat --accent (#f5f5f5) on the palette surface (#fff) is nearly invisible
      in light mode — the keyboard cursor has to read as a solid selected row.
      Mix foreground into background and draw an inset ring; expose the surface
@@ -1159,7 +1161,8 @@ html.native-shell .app-layout {
   color: var(--foreground);
 }
 
-.dark [data-slot='command-item'].jump-palette-item[data-selected='true'] {
+.dark [data-slot='command-item'].jump-palette-item[data-selected='true'],
+.dark [role='option'].jump-palette-item[data-selected='true'] {
   /* Why accent, not the light-mode mix: --accent (#404040) already reads clearly on
      dark surfaces; a low-%% foreground mix was a visible step down from the old row. */
   --jump-palette-selection-surface: var(--accent);
diff --git a/src/renderer/src/components/NewWorkspaceComposerCard.set-location.test.tsx b/src/renderer/src/components/NewWorkspaceComposerCard.set-location.test.tsx
index fe68dc4f53c..9cdea1d7d54 100644
--- a/src/renderer/src/components/NewWorkspaceComposerCard.set-location.test.tsx
+++ b/src/renderer/src/components/NewWorkspaceComposerCard.set-location.test.tsx
@@ -171,6 +171,8 @@ function renderCard(
         onOpenAgentSettings={() => {}}
         advancedOpen={false}
         onToggleAdvanced={() => {}}
+        parentWorktreeId={null}
+        onParentWorktreeIdChange={() => {}}
         createDisabled={false}
         projectError={null}
         creating={false}
diff --git a/src/renderer/src/components/NewWorkspaceComposerCard.test.tsx b/src/renderer/src/components/NewWorkspaceComposerCard.test.tsx
index 9775cd06dae..8206354f916 100644
--- a/src/renderer/src/components/NewWorkspaceComposerCard.test.tsx
+++ b/src/renderer/src/components/NewWorkspaceComposerCard.test.tsx
@@ -230,6 +230,8 @@ function renderCard(
         onReuseSelectedBranchChange={() => {}}
         branchNameOverride=""
         onBranchNameOverrideChange={() => {}}
+        parentWorktreeId={null}
+        onParentWorktreeIdChange={() => {}}
         forkPushWarning={null}
         detectedAgentIds={null}
         onOpenAgentSettings={() => {}}
@@ -306,6 +308,11 @@ function findRunTargetItem(label: string): HTMLElement | undefined {
 
 let current: { container: HTMLDivElement; root: Root } | null = null
 
+function unmountCurrent(): void {
+  act(() => current?.root.unmount())
+  current?.container.remove()
+}
+
 describe('NewWorkspaceComposerCard folder task source mode', () => {
   beforeEach(() => {
     ;(window as unknown as { api: unknown }).api = {
@@ -333,8 +340,7 @@ describe('NewWorkspaceComposerCard folder task source mode', () => {
   })
 
   afterEach(() => {
-    act(() => current?.root.unmount())
-    current?.container.remove()
+    unmountCurrent()
     current = null
     vi.clearAllMocks()
   })
@@ -395,8 +401,7 @@ describe('NewWorkspaceComposerCard folder task source mode', () => {
     )
     expect(collapsedReuse).toBeTruthy()
 
-    act(() => current?.root.unmount())
-    current?.container.remove()
+    unmountCurrent()
 
     current = renderCard({ canReuseSelectedBranch: true, reuseSelectedBranch: true })
     const reuseLabel = [...current.container.querySelectorAll('label')].find((label) =>
@@ -430,8 +435,7 @@ describe('NewWorkspaceComposerCard folder task source mode', () => {
     clickReuseCheckbox()
     expect(offChanges).toEqual([false])
 
-    act(() => current?.root.unmount())
-    current?.container.remove()
+    unmountCurrent()
 
     // Unchecked -> checked (opting into reuse — the action that pins the branch).
     const onChanges: boolean[] = []
@@ -458,8 +462,7 @@ describe('NewWorkspaceComposerCard folder task source mode', () => {
       'Wait for setup to complete before starting agent'
     )
 
-    act(() => current?.root.unmount())
-    current?.container.remove()
+    unmountCurrent()
 
     current = renderCard({
       advancedOpen: true,
@@ -579,6 +582,19 @@ describe('NewWorkspaceComposerCard folder task source mode', () => {
     expect(findInputByLabel(current.container, 'Branch name')).toBeTruthy()
   })
 
+  it('places the parent workspace picker immediately after the branch name field', () => {
+    current = renderCard({
+      advancedOpen: true,
+      branchesEnabled: true
+    })
+
+    const nextField = findInputByLabel(current.container, 'Branch name')?.closest(
+      'div.space-y-1'
+    )?.nextElementSibling
+    expect(nextField?.textContent).toMatch(/Parent worktree(?!.*Note)/)
+    expect(nextField?.nextElementSibling?.textContent).toContain('Note')
+  })
+
   it('does not disable folder workspace creation when only source lookup needs SSH', () => {
     current = renderCard({
       eligibleRepos: [
@@ -886,8 +902,7 @@ describe('NewWorkspaceComposerCard note sizing', () => {
   // Sizing is layout-driven (field-sizing) rather than a JS measure pass, and happy-dom
   // has no layout engine, so these assert the class contract that produces the growth.
   afterEach(() => {
-    act(() => current?.root.unmount())
-    current?.container.remove()
+    unmountCurrent()
     current = null
   })
 
diff --git a/src/renderer/src/components/NewWorkspaceComposerCard.tsx b/src/renderer/src/components/NewWorkspaceComposerCard.tsx
index b0a711cb0eb..c6cca5192ea 100644
--- a/src/renderer/src/components/NewWorkspaceComposerCard.tsx
+++ b/src/renderer/src/components/NewWorkspaceComposerCard.tsx
@@ -55,6 +55,11 @@ export default function NewWorkspaceComposerCard(
     setupConfig,
     setupControlsEnabled = true,
     selectedProjectId = null,
+    parentWorktreeId,
+    onParentWorktreeIdChange,
+    selectedRepoExecutionHostId,
+    selectedRepoProjectId,
+    activeFolderWorkspaceId,
     onAddProjectOverride,
     onNestedDialogOpenChange
   } = props
@@ -302,6 +307,11 @@ export default function NewWorkspaceComposerCard(
           setupRunButtonLabel={setupRunButtonLabel}
           setupSkipButtonLabel={setupSkipButtonLabel}
           showSetupAgentStartupPolicy={showSetupAgentStartupPolicy}
+          parentWorktreeId={parentWorktreeId}
+          onParentWorktreeIdChange={onParentWorktreeIdChange}
+          selectedRepoExecutionHostId={selectedRepoExecutionHostId}
+          selectedRepoProjectId={selectedRepoProjectId}
+          activeFolderWorkspaceId={activeFolderWorkspaceId}
         />
       </div>
       <NewWorkspaceComposerFooter
diff --git a/src/renderer/src/components/new-workspace/ComposerParentWorktreePicker.test.tsx b/src/renderer/src/components/new-workspace/ComposerParentWorktreePicker.test.tsx
new file mode 100644
index 00000000000..c512abcebdb
--- /dev/null
+++ b/src/renderer/src/components/new-workspace/ComposerParentWorktreePicker.test.tsx
@@ -0,0 +1,540 @@
+// @vitest-environment happy-dom
+
+import type React from 'react'
+import type * as WorktreeRepoIndex from '@/store/worktree-repo-index'
+import { cleanup, fireEvent, render } from '@testing-library/react'
+import { afterEach, beforeEach, describe, expect, it, vi } from 'vitest'
+import type { Repo } from '../../../../shared/repo-types'
+import type { WorkspaceLineage, WorktreeLineage } from '../../../../shared/worktree/lineage-types'
+import type { Worktree } from '../../../../shared/worktree/types'
+import { folderWorkspaceKey, worktreeWorkspaceKey } from '../../../../shared/workspace-scope'
+
+type FakeStoreState = {
+  worktreesByRepo: Record<string, Worktree[]>
+  repos: Repo[]
+  projectHostSetups: never[]
+  worktreeLineageById: Record<string, WorktreeLineage>
+  workspaceLineageByChildKey: Record<string, WorkspaceLineage>
+}
+
+const storeState = vi.hoisted(
+  () =>
+    ({
+      worktreesByRepo: {},
+      repos: [],
+      projectHostSetups: [],
+      worktreeLineageById: {},
+      workspaceLineageByChildKey: {}
+    }) as FakeStoreState
+)
+
+const popoverMock = vi.hoisted(() => ({
+  open: false,
+  onOpenChange: undefined as ((open: boolean) => void) | undefined
+}))
+
+const indexSpies = vi.hoisted(() => ({
+  getIndexedAllWorktrees: vi.fn(),
+  getIndexedWorktreeMap: vi.fn(),
+  getIndexedWorktreeById: vi.fn()
+}))
+
+vi.mock('@/i18n/i18n', () => ({
+  translate: (_key: string, fallback: string) => fallback
+}))
+
+vi.mock('react-i18next', () => ({
+  useTranslation: () => ({ t: (_key: string, fallback: string) => fallback })
+}))
+
+vi.mock('@/store', () => ({
+  useAppStore: (selector: (state: FakeStoreState) => unknown) => selector(storeState)
+}))
+
+// Spies wrap the real projections, so exclusion rules stay under test while call
+// counts prove when enumeration happens.
+vi.mock('@/store/worktree-repo-index', async (importOriginal) => {
+  const actual = await importOriginal<typeof WorktreeRepoIndex>()
+  indexSpies.getIndexedAllWorktrees.mockImplementation(actual.getIndexedAllWorktrees)
+  indexSpies.getIndexedWorktreeMap.mockImplementation(actual.getIndexedWorktreeMap)
+  indexSpies.getIndexedWorktreeById.mockImplementation(actual.getIndexedWorktreeById)
+  return { ...actual, ...indexSpies }
+})
+
+vi.mock('@/components/ui/popover', async () => {
+  const { cloneElement } = await import('react')
+  return {
+    Popover: ({
+      children,
+      open,
+      onOpenChange
+    }: {
+      children: React.ReactNode
+      open?: boolean
+      onOpenChange?: (open: boolean) => void
+    }) => {
+      popoverMock.open = open ?? false
+      popoverMock.onOpenChange = onOpenChange
+      return <div>{children}</div>
+    },
+    // Radix `asChild` renders the child itself and owns its click; mirror that.
+    PopoverTrigger: ({ children }: { children: React.ReactElement }) =>
+      cloneElement(children as React.ReactElement<{ onClick?: () => void }>, {
+        onClick: () => popoverMock.onOpenChange?.(!popoverMock.open)
+      }),
+    // Radix mounts content only while open — the property the lazy list relies on.
+    PopoverContent: ({ children }: { children: React.ReactNode }) =>
+      popoverMock.open ? <div>{children}</div> : null
+  }
+})
+
+vi.mock('@/components/ui/command', () => ({
+  Command: ({ children, className }: { children: React.ReactNode; className?: string }) => (
+    <div className={className}>{children}</div>
+  ),
+  CommandInput: ({
+    ref,
+    value,
+    placeholder,
+    onValueChange,
+    onKeyDown,
+    onKeyUp,
+    onCompositionStart,
+    onCompositionEnd
+  }: {
+    ref?: React.Ref<HTMLInputElement>
+    value?: string
+    placeholder?: string
+    onValueChange?: (value: string) => void
+    onKeyDown?: React.KeyboardEventHandler<HTMLInputElement>
+    onKeyUp?: React.KeyboardEventHandler<HTMLInputElement>
+    onCompositionStart?: React.CompositionEventHandler<HTMLInputElement>
+    onCompositionEnd?: React.CompositionEventHandler<HTMLInputElement>
+  }) => (
+    <input
+      ref={ref}
+      data-slot="command-input"
+      value={value}
+      placeholder={placeholder}
+      onChange={(event) => onValueChange?.(event.target.value)}
+      onKeyDown={onKeyDown}
+      onKeyUp={onKeyUp}
+      onCompositionStart={onCompositionStart}
+      onCompositionEnd={onCompositionEnd}
+    />
+  ),
+  CommandList: ({
+    ref,
+    children,
+    className
+  }: {
+    ref?: React.Ref<HTMLDivElement>
+    children: React.ReactNode
+    className?: string
+  }) => (
+    <div ref={ref} className={className}>
+      {children}
+    </div>
+  )
+}))
+
+// The virtual window needs real layout the test DOM has none of; render every row.
+vi.mock('@tanstack/react-virtual', () => ({
+  useVirtualizer: ({ count }: { count: number }) => ({
+    getTotalSize: () => count * 44,
+    getVirtualItems: () =>
+      Array.from({ length: count }, (_, index) => ({
+        index,
+        key: index,
+        start: index * 44,
+        size: 44
+      })),
+    scrollToIndex: vi.fn(),
+    scrollToOffset: vi.fn()
+  })
+}))
+
+const { ComposerParentWorktreePicker } = await import('./ComposerParentWorktreePicker')
+
+const REPO_ID = 'repo1'
+
+function makeRepo(id: string): Repo {
+  return {
+    id,
+    path: `/src/${id}`,
+    displayName: id,
+    badgeColor: '#111111',
+    addedAt: 0
+  } as Repo
+}
+
+function makeWorktree(overrides: Partial<Worktree> & { id: string }): Worktree {
+  return {
+    repoId: REPO_ID,
+    path: `/work/${overrides.id}`,
+    head: 'abc123',
+    branch: 'refs/heads/feature',
+    isBare: false,
+    isMainWorktree: false,
+    displayName: overrides.id,
+    comment: '',
+    linkedIssue: null,
+    linkedPR: null,
+    linkedLinearIssue: null,
+    isArchived: false,
+    isUnread: false,
+    isPinned: false,
+    sortOrder: 0,
+    lastActivityAt: 0,
+    ...overrides
+  }
+}
+
+function seed(worktrees: Worktree[], repoIds: string[] = [REPO_ID]): void {
+  const byRepo: Record<string, Worktree[]> = {}
+  for (const worktree of worktrees) {
+    byRepo[worktree.repoId] = [...(byRepo[worktree.repoId] ?? []), worktree]
+  }
+  storeState.worktreesByRepo = byRepo
+  storeState.repos = repoIds.map(makeRepo)
+}
+
+function trigger(): HTMLButtonElement {
+  const node = document.querySelector<HTMLButtonElement>('button[role="combobox"]')
+  if (!node) {
+    throw new Error('parent picker trigger not found')
+  }
+  return node
+}
+
+function rows(): HTMLElement[] {
+  return Array.from(document.querySelectorAll<HTMLElement>('[role="option"]'))
+}
+
+function candidateLabels(): string[] {
+  return rows()
+    .slice(1)
+    .map((row) => row.textContent ?? '')
+}
+
+function searchInput(): HTMLInputElement {
+  const node = document.querySelector<HTMLInputElement>('[data-slot="command-input"]')
+  if (!node) {
+    throw new Error('parent picker search input not found')
+  }
+  return node
+}
+
+function rowFor(label: string): HTMLElement {
+  const row = rows().find((node) => node.textContent?.includes(label))
+  if (!row) {
+    throw new Error(`row not found for ${label}`)
+  }
+  return row
+}
+
+beforeEach(() => {
+  popoverMock.open = false
+  popoverMock.onOpenChange = undefined
+  storeState.worktreesByRepo = {}
+  storeState.repos = []
+  storeState.worktreeLineageById = {}
+  storeState.workspaceLineageByChildKey = {}
+  indexSpies.getIndexedAllWorktrees.mockClear()
+  indexSpies.getIndexedWorktreeMap.mockClear()
+  indexSpies.getIndexedWorktreeById.mockClear()
+})
+
+afterEach(cleanup)
+
+describe('ComposerParentWorktreePicker', () => {
+  it('enumerates candidate worktrees only once the popover opens', () => {
+    seed([makeWorktree({ id: 'alpha' }), makeWorktree({ id: 'beta' })])
+
+    render(<ComposerParentWorktreePicker repoId={REPO_ID} value="alpha" onChange={vi.fn()} />)
+
+    // The closed trigger resolves one name from the shared index; it never enumerates.
+    expect(indexSpies.getIndexedWorktreeById).toHaveBeenCalled()
+    expect(indexSpies.getIndexedAllWorktrees).not.toHaveBeenCalled()
+    expect(indexSpies.getIndexedWorktreeMap).not.toHaveBeenCalled()
+
+    fireEvent.click(trigger())
+
+    expect(indexSpies.getIndexedAllWorktrees).toHaveBeenCalled()
+    expect(indexSpies.getIndexedWorktreeMap).toHaveBeenCalled()
+  })
+
+  it('shows "No parent" on the closed trigger when nothing is picked', () => {
+    seed([makeWorktree({ id: 'alpha' })])
+
+    render(<ComposerParentWorktreePicker repoId={REPO_ID} value={null} onChange={vi.fn()} />)
+
+    expect(trigger().textContent).toContain('No parent')
+  })
+
+  it('shows the picked worktree display name on the closed trigger', () => {
+    seed([makeWorktree({ id: 'alpha', displayName: 'Alpha workspace' })])
+
+    render(<ComposerParentWorktreePicker repoId={REPO_ID} value="alpha" onChange={vi.fn()} />)
+
+    expect(trigger().textContent).toContain('Alpha workspace')
+    expect(trigger().textContent).not.toContain('No parent')
+  })
+
+  it('reports the picked worktree id and closes when a candidate row is clicked', () => {
+    const onChange = vi.fn()
+    seed([makeWorktree({ id: 'alpha', displayName: 'Alpha' })])
+
+    render(<ComposerParentWorktreePicker repoId={REPO_ID} value={null} onChange={onChange} />)
+    fireEvent.click(trigger())
+    fireEvent.click(rowFor('Alpha'))
+
+    expect(onChange).toHaveBeenCalledWith('alpha')
+    expect(rows()).toHaveLength(0)
+  })
+
+  it('clears the pick when the pinned "No parent" row is clicked', () => {
+    const onChange = vi.fn()
+    seed([makeWorktree({ id: 'alpha', displayName: 'Alpha' })])
+
+    render(<ComposerParentWorktreePicker repoId={REPO_ID} value="alpha" onChange={onChange} />)
+    fireEvent.click(trigger())
+    fireEvent.click(rows()[0])
+
+    expect(onChange).toHaveBeenCalledWith(null)
+    expect(rows()).toHaveLength(0)
+  })
+
+  it('excludes archived worktrees and worktrees from another repo', () => {
+    seed(
+      [
+        makeWorktree({ id: 'alpha', displayName: 'Alpha' }),
+        makeWorktree({ id: 'archived', displayName: 'Archived', isArchived: true }),
+        makeWorktree({ id: 'other', displayName: 'Other repo', repoId: 'repo2' })
+      ],
+      [REPO_ID, 'repo2']
+    )
+
+    render(<ComposerParentWorktreePicker repoId={REPO_ID} value={null} onChange={vi.fn()} />)
+    fireEvent.click(trigger())
+
+    expect(candidateLabels().join(' ')).toContain('Alpha')
+    expect(candidateLabels().join(' ')).not.toContain('Archived')
+    expect(candidateLabels().join(' ')).not.toContain('Other repo')
+  })
+
+  it('excludes candidates on another execution host or project', () => {
+    seed([
+      makeWorktree({ id: 'same', displayName: 'Same host', hostId: 'local', projectId: 'proj1' }),
+      makeWorktree({
+        id: 'otherHost',
+        displayName: 'Other host',
+        hostId: 'ssh:box',
+        projectId: 'proj1'
+      }),
+      makeWorktree({
+        id: 'otherProject',
+        displayName: 'Other project',
+        hostId: 'local',
+        projectId: 'proj2'
+      })
+    ])
+
+    render(
+      <ComposerParentWorktreePicker
+        repoId={REPO_ID}
+        executionHostId="local"
+        projectId="proj1"
+        value={null}
+        onChange={vi.fn()}
+      />
+    )
+    fireEvent.click(trigger())
+
+    expect(candidateLabels().join(' ')).toContain('Same host')
+    expect(candidateLabels().join(' ')).not.toContain('Other host')
+    expect(candidateLabels().join(' ')).not.toContain('Other project')
+  })
+
+  // A worktree with no recorded hostId inherits its repo's host, which is the child's host too.
+  it('keeps candidates whose host or project is unrecorded', () => {
+    seed([makeWorktree({ id: 'unscoped', displayName: 'Unscoped' })])
+
+    render(
+      <ComposerParentWorktreePicker
+        repoId={REPO_ID}
+        executionHostId="local"
+        projectId="proj1"
+        value={null}
+        onChange={vi.fn()}
+      />
+    )
+    fireEvent.click(trigger())
+
+    expect(candidateLabels().join(' ')).toContain('Unscoped')
+  })
+
+  it('restricts candidates to the active folder workspace subtree', () => {
+    const attached = makeWorktree({
+      id: 'attached',
+      displayName: 'Attached',
+      instanceId: 'attached-instance'
+    })
+    const nested = makeWorktree({
+      id: 'nested',
+      displayName: 'Nested',
+      instanceId: 'nested-instance'
+    })
+    const outside = makeWorktree({ id: 'outside', displayName: 'Outside' })
+    seed([attached, nested, outside])
+    storeState.workspaceLineageByChildKey = {
+      [worktreeWorkspaceKey(attached.id)]: {
+        childWorkspaceKey: worktreeWorkspaceKey(attached.id),
+        childInstanceId: attached.instanceId ?? null,
+        parentWorkspaceKey: folderWorkspaceKey('folder-1'),
+        parentInstanceId: null,
+        origin: 'manual',
+        capture: { source: 'active-workspace', confidence: 'explicit' },
+        createdAt: 1
+      }
+    }
+    storeState.worktreeLineageById = {
+      [nested.id]: {
+        worktreeId: nested.id,
+        worktreeInstanceId: 'nested-instance',
+        parentWorktreeId: attached.id,
+        parentWorktreeInstanceId: 'attached-instance',
+        origin: 'manual',
+        capture: { source: 'manual-action', confidence: 'explicit' },
+        createdAt: 2
+      }
+    }
+
+    render(
+      <ComposerParentWorktreePicker
+        repoId={REPO_ID}
+        value={null}
+        onChange={vi.fn()}
+        activeFolderWorkspaceId="folder-1"
+      />
+    )
+    fireEvent.click(trigger())
+
+    const labels = candidateLabels().join(' ')
+    expect(labels).toContain('Attached')
+    expect(labels).toContain('Nested')
+    expect(labels).not.toContain('Outside')
+  })
+
+  it('keeps the trigger inert while disabled', () => {
+    seed([makeWorktree({ id: 'alpha', displayName: 'Alpha' })])
+
+    render(
+      <ComposerParentWorktreePicker repoId={REPO_ID} value={null} onChange={vi.fn()} disabled />
+    )
+    fireEvent.click(trigger())
+
+    expect(trigger().disabled).toBe(true)
+    expect(rows()).toHaveLength(0)
+  })
+
+  it('picks the top match when Enter follows a search query', () => {
+    const onChange = vi.fn()
+    seed([
+      makeWorktree({ id: 'alpha', displayName: 'Alpha' }),
+      makeWorktree({ id: 'beta', displayName: 'Beta' })
+    ])
+
+    render(<ComposerParentWorktreePicker repoId={REPO_ID} value={null} onChange={onChange} />)
+    fireEvent.click(trigger())
+    fireEvent.change(searchInput(), { target: { value: 'Beta' } })
+    fireEvent.keyDown(searchInput(), { key: 'Enter', keyCode: 13 })
+
+    // Regression: the highlight used to reset onto the pinned "No parent" row, so the
+    // standard type-then-Enter flow cleared the parent instead of picking the match.
+    expect(onChange).toHaveBeenCalledWith('beta')
+  })
+
+  it('clears the parent when Enter is pressed with no search query', () => {
+    const onChange = vi.fn()
+    seed([makeWorktree({ id: 'alpha', displayName: 'Alpha' })])
+
+    render(<ComposerParentWorktreePicker repoId={REPO_ID} value="alpha" onChange={onChange} />)
+    fireEvent.click(trigger())
+    fireEvent.keyDown(searchInput(), { key: 'Enter', keyCode: 13 })
+
+    expect(onChange).toHaveBeenCalledWith(null)
+  })
+
+  it('keeps the parent when Enter only confirms a CJK composition', () => {
+    const onChange = vi.fn()
+    seed([makeWorktree({ id: 'alpha', displayName: 'Alpha' })])
+
+    render(<ComposerParentWorktreePicker repoId={REPO_ID} value={null} onChange={onChange} />)
+    fireEvent.click(trigger())
+    fireEvent.compositionStart(searchInput())
+    // The confirming Enter arrives twice: the marked keydown, then an unmarked redispatch.
+    fireEvent.keyDown(searchInput(), { key: 'Enter', keyCode: 229 })
+    fireEvent.keyDown(searchInput(), { key: 'Enter', keyCode: 13 })
+
+    expect(onChange).not.toHaveBeenCalled()
+    expect(rows().length).toBeGreaterThan(0)
+  })
+
+  it('falls back to "No parent" on the trigger when the picked parent is archived', () => {
+    seed([makeWorktree({ id: 'alpha', displayName: 'Alpha workspace', isArchived: true })])
+
+    render(<ComposerParentWorktreePicker repoId={REPO_ID} value="alpha" onChange={vi.fn()} />)
+
+    expect(trigger().textContent).not.toContain('Alpha workspace')
+    expect(trigger().textContent).toContain('No parent')
+  })
+
+  it('excludes a folder root whose lineage row is instance-stale', () => {
+    const attached = makeWorktree({
+      id: 'attached',
+      displayName: 'Attached',
+      instanceId: 'current-instance'
+    })
+    seed([attached])
+    storeState.workspaceLineageByChildKey = {
+      [worktreeWorkspaceKey(attached.id)]: {
+        childWorkspaceKey: worktreeWorkspaceKey(attached.id),
+        childInstanceId: 'deleted-and-recreated',
+        parentWorkspaceKey: folderWorkspaceKey('folder-1'),
+        parentInstanceId: null,
+        origin: 'manual',
+        capture: { source: 'active-workspace', confidence: 'explicit' },
+        createdAt: 1
+      }
+    }
+
+    render(
+      <ComposerParentWorktreePicker
+        repoId={REPO_ID}
+        value={null}
+        onChange={vi.fn()}
+        activeFolderWorkspaceId="folder-1"
+      />
+    )
+    fireEvent.click(trigger())
+
+    expect(candidateLabels().join(' ')).not.toContain('Attached')
+  })
+
+  it('closes an open popover when the drawer collapses the trigger', () => {
+    seed([makeWorktree({ id: 'alpha', displayName: 'Alpha' })])
+
+    const view = render(
+      <ComposerParentWorktreePicker repoId={REPO_ID} value={null} onChange={vi.fn()} />
+    )
+    fireEvent.click(trigger())
+    expect(rows().length).toBeGreaterThan(0)
+
+    view.rerender(
+      <ComposerParentWorktreePicker repoId={REPO_ID} value={null} onChange={vi.fn()} disabled />
+    )
+
+    expect(rows()).toHaveLength(0)
+  })
+})
diff --git a/src/renderer/src/components/new-workspace/ComposerParentWorktreePicker.tsx b/src/renderer/src/components/new-workspace/ComposerParentWorktreePicker.tsx
new file mode 100644
index 00000000000..41c22978f14
--- /dev/null
+++ b/src/renderer/src/components/new-workspace/ComposerParentWorktreePicker.tsx
@@ -0,0 +1,429 @@
+import React, { useCallback, useEffect, useId, useMemo, useRef, useState } from 'react'
+import { useTranslation } from 'react-i18next'
+import { Check, ChevronsUpDown, GitBranch } from 'lucide-react'
+import { useVirtualizer } from '@tanstack/react-virtual'
+import { Button } from '@/components/ui/button'
+import { Command, CommandInput, CommandList } from '@/components/ui/command'
+import { Popover, PopoverContent, PopoverTrigger } from '@/components/ui/popover'
+import { cn } from '@/lib/utils'
+import {
+  isImeCompositionKeyDown,
+  useImeEnterGestureOwnership
+} from '@/lib/ime-composition-keyboard-event'
+import { translate } from '@/i18n/i18n'
+import { useAppStore } from '@/store'
+import {
+  getIndexedAllWorktrees,
+  getIndexedWorktreeById,
+  getIndexedWorktreeMap
+} from '@/store/worktree-repo-index'
+import { compareWorktreeDisplayName } from '@/lib/worktree-display-name-order'
+import { branchDisplayName } from '@/components/sidebar/WorktreeCardHelpers'
+import { getCyclicProjectedWorktreeLineageIds } from '@/components/sidebar/worktree-lineage-projection'
+import {
+  clampWorktreeParentPickerIndex,
+  filterWorktreeParentCandidates
+} from '@/components/sidebar/worktree-parent-picker-filtering'
+import {
+  PICKER_LIST_MAX_HEIGHT,
+  PICKER_ROW_HEIGHT,
+  PICKER_ROW_OVERSCAN
+} from '@/components/sidebar/worktree-parent-picker-placement'
+import {
+  getLineageChildrenByParentId,
+  getLineageChildWorktree
+} from '@/components/right-sidebar/folder-workspace-attached-worktrees'
+import { COMBOBOX_POPOVER_SURFACE } from './type-ahead-combobox-styles'
+import {
+  sharesWorktreeLineageBoundary,
+  type WorktreeLineageBoundary
+} from '../../../../shared/resolved-worktree-lineage'
+import { folderWorkspaceKey } from '../../../../shared/workspace-scope'
+import type { WorkspaceLineage, WorktreeLineage } from '../../../../shared/worktree/lineage-types'
+import type { Worktree } from '../../../../shared/worktree/types'
+import type { ExecutionHostId } from '../../../../shared/execution-host'
+
+/** Single-line row: text-sm leading (20px) over py-2. Set as the row's explicit height. */
+const NO_PARENT_ROW_HEIGHT = 36
+const NO_PARENT_ROW_KEY = 'no-parent'
+
+type ComposerParentWorktreePickerProps = {
+  repoId: string
+  /** Parent must belong to the same execution host that will create the child. */
+  executionHostId?: ExecutionHostId | null
+  projectId?: string | null
+  value: string | null
+  onChange: (id: string | null) => void
+  disabled?: boolean
+  /** When the active workspace is a folder, restrict candidates to that folder's subtree. */
+  activeFolderWorkspaceId?: string | null
+}
+
+type ParentWorktreeCandidateListProps = {
+  repoId: string
+  executionHostId?: ExecutionHostId | null
+  projectId?: string | null
+  value: string | null
+  activeFolderWorkspaceId: string | null
+  onSelect: (id: string | null) => void
+}
+
+/**
+ * Parent picker for the composer's Advanced drawer. Nesting only — the base
+ * branch is unaffected.
+ *
+ * Everything that enumerates worktrees lives in the inner list, which Radix
+ * mounts on open, so a closed picker costs one string selector and nothing else.
+ */
+function ComposerParentWorktreePickerImpl({
+  repoId,
+  executionHostId,
+  projectId,
+  value,
+  onChange,
+  disabled = false,
+  activeFolderWorkspaceId = null
+}: ComposerParentWorktreePickerProps): React.JSX.Element {
+  // Why: subscribe so translate() copy refreshes on language change without a remount.
+  useTranslation()
+  const [open, setOpen] = useState(false)
+  const labelId = `${useId()}label`
+
+  // Why: an archived parent is already gone from the candidate list and the sidebar would
+  // drop the edge, so showing its name would promise nesting the create can't deliver.
+  const parentName = useAppStore((s) => {
+    if (!value) {
+      return null
+    }
+    const parent = getIndexedWorktreeById(s.worktreesByRepo, value)
+    return parent && !parent.isArchived ? parent.displayName : null
+  })
+
+  // Why: the trigger goes inert when the Advanced drawer collapses, but the portaled
+  // popover does not — it would linger detached from a control the user can't reach.
+  // Adjusted during render (not in an effect) so the stale-open frame never paints.
+  if (open && disabled) {
+    setOpen(false)
+  }
+
+  const handleSelect = useCallback(
+    (nextId: string | null) => {
+      onChange(nextId)
+      setOpen(false)
+    },
+    [onChange]
+  )
+
+  return (
+    <div className="space-y-1.5">
+      <span id={labelId} className="block text-xs font-medium text-muted-foreground">
+        {translate('auto.components.ComposerParentWorktreePicker.label', 'Parent worktree')}
+      </span>
+      <Popover open={open} onOpenChange={setOpen}>
+        <PopoverTrigger asChild>
+          <Button
+            type="button"
+            variant="outline"
+            role="combobox"
+            aria-expanded={open}
+            aria-labelledby={labelId}
+            disabled={disabled}
+            className="h-9 w-full justify-between border-input px-3 text-sm font-normal text-foreground focus:border-ring focus:ring-[3px] focus:ring-ring/50"
+          >
+            <span className="truncate">
+              {parentName ??
+                translate('auto.components.ComposerParentWorktreePicker.noParent', 'No parent')}
+            </span>
+            <ChevronsUpDown className="size-3.5 shrink-0 opacity-50" />
+          </Button>
+        </PopoverTrigger>
+        <PopoverContent
+          align="start"
+          className={cn(
+            'flex w-[var(--radix-popover-trigger-width)] min-w-[17rem] flex-col p-0',
+            COMBOBOX_POPOVER_SURFACE
+          )}
+          // Why: Radix would focus the content wrapper; the search box is the real target.
+          onOpenAutoFocus={(event) => {
+            event.preventDefault()
+            const content = event.currentTarget
+            if (content instanceof HTMLElement) {
+              content.querySelector<HTMLInputElement>('[data-slot="command-input"]')?.focus()
+            }
+          }}
+        >
+          <ParentWorktreeCandidateList
+            repoId={repoId}
+            executionHostId={executionHostId}
+            projectId={projectId}
+            value={value}
+            activeFolderWorkspaceId={activeFolderWorkspaceId}
+            onSelect={handleSelect}
+          />
+        </PopoverContent>
+      </Popover>
+      <p className="text-[11px] text-muted-foreground">
+        {translate(
+          'auto.components.ComposerParentWorktreePicker.description',
+          'Nests this workspace under another in the sidebar. Does not change the base branch.'
+        )}
+      </p>
+    </div>
+  )
+}
+
+/** Worktrees reachable from the folder workspace, so a pick can't drop the new one out of it. */
+function getFolderWorkspaceSubtreeIds(
+  folderWorkspaceId: string,
+  workspaceLineageByChildKey: Readonly<Record<string, WorkspaceLineage>>,
+  worktreeLineageById: Record<string, WorktreeLineage>,
+  worktreeById: Map<string, Worktree>
+): Set<string> {
+  const folderKey = folderWorkspaceKey(folderWorkspaceId)
+  const rootIds = new Set<string>()
+  for (const lineage of Object.values(workspaceLineageByChildKey)) {
+    if (lineage.parentWorkspaceKey !== folderKey) {
+      continue
+    }
+    // Why: the folder view drops archived and instance-stale rows, so accepting them here
+    // would offer a parent whose whole branch the folder never actually shows.
+    const rootWorktree = getLineageChildWorktree(lineage, worktreeById)
+    if (rootWorktree) {
+      rootIds.add(rootWorktree.id)
+    }
+  }
+
+  const subtreeIds = new Set(rootIds)
+  for (const children of getLineageChildrenByParentId(
+    worktreeLineageById,
+    worktreeById,
+    rootIds
+  ).values()) {
+    for (const child of children) {
+      subtreeIds.add(child.id)
+    }
+  }
+  return subtreeIds
+}
+
+function ParentWorktreeCandidateList({
+  repoId,
+  executionHostId,
+  projectId,
+  value,
+  activeFolderWorkspaceId,
+  onSelect
+}: ParentWorktreeCandidateListProps): React.JSX.Element {
+  const worktreesByRepo = useAppStore((s) => s.worktreesByRepo)
+  const worktreeLineageById = useAppStore((s) => s.worktreeLineageById)
+  const workspaceLineageByChildKey = useAppStore((s) => s.workspaceLineageByChildKey)
+  const listRef = useRef<HTMLDivElement>(null)
+  const inputRef = useRef<HTMLInputElement>(null)
+  const imeEnter = useImeEnterGestureOwnership()
+  const optionIdPrefix = `${useId()}option`
+  const [search, setSearch] = useState('')
+  const [highlightedIndex, setHighlightedIndex] = useState(0)
+
+  const candidates = useMemo(() => {
+    // Why `?? undefined`: an unresolved host or project is "not known yet", not "no host", and
+    // the boundary check reads undefined on either side as a wildcard. A candidate in this repo
+    // with no recorded hostId inherits that repo's host, so it is on the child's host too.
+    const childBoundary: WorktreeLineageBoundary = {
+      repoId,
+      hostId: executionHostId ?? undefined,
+      projectId: projectId ?? undefined
+    }
+    const worktreeMap = getIndexedWorktreeMap(worktreesByRepo)
+    const cyclicLineageIds = getCyclicProjectedWorktreeLineageIds(worktreeLineageById, worktreeMap)
+    const folderSubtreeIds = activeFolderWorkspaceId
+      ? getFolderWorkspaceSubtreeIds(
+          activeFolderWorkspaceId,
+          workspaceLineageByChildKey,
+          worktreeLineageById,
+          worktreeMap
+        )
+      : null
+    return getIndexedAllWorktrees(worktreesByRepo)
+      .filter(
+        (candidate) =>
+          candidate.repoId === repoId &&
+          !candidate.isArchived &&
+          sharesWorktreeLineageBoundary(childBoundary, candidate) &&
+          !cyclicLineageIds.has(candidate.id) &&
+          (folderSubtreeIds === null || folderSubtreeIds.has(candidate.id))
+      )
+      .sort(compareWorktreeDisplayName)
+  }, [
+    activeFolderWorkspaceId,
+    executionHostId,
+    projectId,
+    repoId,
+    workspaceLineageByChildKey,
+    worktreeLineageById,
+    worktreesByRepo
+  ])
+
+  const filtered = useMemo(
+    () => filterWorktreeParentCandidates(candidates, search),
+    [candidates, search]
+  )
+  // Index 0 is the pinned "No parent" row; candidates start at 1.
+  const activeIndex = clampWorktreeParentPickerIndex(highlightedIndex, filtered.length + 1)
+
+  // Why: the "No parent" row is virtualized as index 0 rather than pinned above the
+  // scroller. A row outside the virtual container shifts every item's true position
+  // without the virtualizer knowing, so scrollToIndex would land short by that height.
+  const virtualizer = useVirtualizer({
+    count: filtered.length + 1,
+    getScrollElement: () => listRef.current,
+    estimateSize: (index) => (index === 0 ? NO_PARENT_ROW_HEIGHT : PICKER_ROW_HEIGHT),
+    overscan: PICKER_ROW_OVERSCAN,
+    getItemKey: (index) => (index === 0 ? NO_PARENT_ROW_KEY : (filtered[index - 1]?.id ?? index)),
+    // Why: the list mounts inside a popover that measures on the next frame, so
+    // seed the viewport to avoid a blank first paint.
+    initialRect: { width: 0, height: PICKER_LIST_MAX_HEIGHT }
+  })
+
+  const moveHighlight = useCallback(
+    (nextIndex: number) => {
+      setHighlightedIndex(nextIndex)
+      virtualizer.scrollToIndex(nextIndex, { align: 'auto' })
+    },
+    [virtualizer]
+  )
+
+  const handleSearchChange = useCallback(
+    (nextSearch: string) => {
+      // Why: re-ranking on each keystroke makes any prior highlight meaningless. A query
+      // highlights the top match so Enter picks it; index 0 clears the parent, which is
+      // never what typing a name means. The clamp drops it back to 0 when nothing matches.
+      setSearch(nextSearch)
+      setHighlightedIndex(nextSearch.trim().length > 0 ? 1 : 0)
+      virtualizer.scrollToOffset(0)
+    },
+    [virtualizer]
+  )
+
+  const handleKeyDown = useCallback(
+    (event: React.KeyboardEvent<HTMLInputElement>) => {
+      // Why: cmdk's root handler only knows the mounted virtual window, so own navigation here.
+      // A CJK confirm sends two Enter keydowns and only the first is marked, so the marked-only
+      // check must be paired with the gesture carry or the unmarked one commits a selection.
+      if (imeEnter.ownsKeyDown(event) || isImeCompositionKeyDown(event)) {
+        return
+      }
+      const navigate = (nextIndex: number): void => {
+        event.preventDefault()
+        event.stopPropagation()
+        moveHighlight(clampWorktreeParentPickerIndex(nextIndex, filtered.length + 1))
+      }
+      if (event.key === 'ArrowDown') {
+        navigate(activeIndex + 1)
+      } else if (event.key === 'ArrowUp') {
+        navigate(activeIndex - 1)
+      } else if (event.key === 'Home') {
+        navigate(0)
+      } else if (event.key === 'End') {
+        navigate(filtered.length)
+      } else if (event.key === 'Enter') {
+        const candidate = activeIndex === 0 ? null : filtered[activeIndex - 1]
+        if (activeIndex === 0 || candidate) {
+          event.preventDefault()
+          event.stopPropagation()
+          onSelect(candidate?.id ?? null)
+        }
+      }
+    },
+    [activeIndex, filtered, imeEnter, moveHighlight, onSelect]
+  )
+
+  // Why: cmdk's Input owns aria-activedescendant and points it at its own empty
+  // item registry while we drive selection, so re-point it after every commit.
+  useEffect(() => {
+    inputRef.current?.setAttribute('aria-activedescendant', `${optionIdPrefix}-${activeIndex}`)
+  })
+
+  const virtualRows = virtualizer.getVirtualItems()
+
+  return (
+    <Command shouldFilter={false} className="min-h-0 bg-transparent">
+      <CommandInput
+        ref={inputRef}
+        value={search}
+        onValueChange={handleSearchChange}
+        onKeyDown={handleKeyDown}
+        onKeyUp={imeEnter.onKeyUp}
+        onCompositionStart={() => imeEnter.setComposing(true)}
+        onCompositionEnd={() => imeEnter.setComposing(false)}
+        wrapperClassName="shrink-0"
+        placeholder={translate(
+          'auto.components.ComposerParentWorktreePicker.searchPlaceholder',
+          'Search workspaces...'
+        )}
+      />
+      <CommandList ref={listRef} className="max-h-72 min-h-0 flex-1">
+        <div className="relative w-full" style={{ height: virtualizer.getTotalSize() }}>
+          {virtualRows.map((virtualRow) => {
+            const rowIndex = virtualRow.index
+            const candidate = rowIndex === 0 ? null : filtered[rowIndex - 1]
+            if (rowIndex !== 0 && !candidate) {
+              return null
+            }
+            const isHighlighted = rowIndex === activeIndex
+            return (
+              <div
+                key={virtualRow.key}
+                id={`${optionIdPrefix}-${rowIndex}`}
+                role="option"
+                aria-selected={(candidate?.id ?? null) === value}
+                data-selected={isHighlighted || undefined}
+                // Why `jump-palette-item`: selection chrome lives in main.css — flat accent is invisible on light popovers.
+                className="jump-palette-item absolute left-0 top-0 flex w-full cursor-default select-none items-center gap-2 overflow-hidden rounded-sm px-2 py-2 text-sm outline-none"
+                style={{
+                  height: virtualRow.size,
+                  transform: `translateY(${virtualRow.start}px)`
+                }}
+                onPointerMove={() => setHighlightedIndex(rowIndex)}
+                onClick={() => onSelect(candidate?.id ?? null)}
+              >
+                <Check
+                  className={cn(
+                    'size-3.5 shrink-0',
+                    (candidate?.id ?? null) !== value && 'opacity-0'
+                  )}
+                />
+                {candidate ? (
+                  <div className="min-w-0 flex-1">
+                    <div className="truncate text-[13px] font-medium">{candidate.displayName}</div>
+                    <div className="mt-1 flex min-w-0 items-center gap-1.5 text-[11px] leading-none text-muted-foreground">
+                      <GitBranch className="size-3 shrink-0" />
+                      <span className="truncate">{branchDisplayName(candidate.branch)}</span>
+                    </div>
+                  </div>
+                ) : (
+                  <span className="truncate">
+                    {translate(
+                      'auto.components.ComposerParentWorktreePicker.noParent',
+                      'No parent'
+                    )}
+                  </span>
+                )}
+              </div>
+            )
+          })}
+        </div>
+        {filtered.length === 0 && search.trim().length > 0 ? (
+          <div className="py-6 text-center text-sm text-muted-foreground">
+            {translate('auto.components.ComposerParentWorktreePicker.noMatches', 'No matches.')}
+          </div>
+        ) : null}
+      </CommandList>
+    </Command>
+  )
+}
+
+/** Why: every prop is a primitive or a stable callback, so the composer's per-keystroke
+ *  renders stop here instead of re-rendering the popover subtree. */
+export const ComposerParentWorktreePicker = React.memo(ComposerParentWorktreePickerImpl)
+
+export default ComposerParentWorktreePicker
diff --git a/src/renderer/src/components/new-workspace/NewWorkspaceComposerAdvancedSection.tsx b/src/renderer/src/components/new-workspace/NewWorkspaceComposerAdvancedSection.tsx
index 549370ee029..f7b18f6ebaa 100644
--- a/src/renderer/src/components/new-workspace/NewWorkspaceComposerAdvancedSection.tsx
+++ b/src/renderer/src/components/new-workspace/NewWorkspaceComposerAdvancedSection.tsx
@@ -11,6 +11,7 @@ import {
   shouldHandleTextControlPaste
 } from '@/lib/text-control-paste'
 import { translate } from '@/i18n/i18n'
+import { ComposerParentWorktreePicker } from './ComposerParentWorktreePicker'
 import type { NewWorkspaceComposerCardProps } from './new-workspace-composer-card-props'
 
 function SetupCommandPreview({
@@ -37,6 +38,11 @@ type NewWorkspaceComposerAdvancedSectionProps = Pick<
   | 'branchesEnabled'
   | 'branchNameOverride'
   | 'onBranchNameOverrideChange'
+  | 'parentWorktreeId'
+  | 'onParentWorktreeIdChange'
+  | 'selectedRepoExecutionHostId'
+  | 'selectedRepoProjectId'
+  | 'activeFolderWorkspaceId'
   | 'note'
   | 'onNoteChange'
   | 'setupControlsEnabled'
@@ -74,6 +80,11 @@ export function NewWorkspaceComposerAdvancedSection({
   branchNameInputId,
   branchNameOverride,
   onBranchNameOverrideChange,
+  parentWorktreeId = null,
+  onParentWorktreeIdChange,
+  selectedRepoExecutionHostId,
+  selectedRepoProjectId,
+  activeFolderWorkspaceId = null,
   note,
   onNoteChange,
   setupControlsEnabled = true,
@@ -191,6 +202,18 @@ export function NewWorkspaceComposerAdvancedSection({
             </div>
           ) : null}
 
+          {selectedRepoIsGit && branchesEnabled && onParentWorktreeIdChange ? (
+            <ComposerParentWorktreePicker
+              repoId={repoId}
+              executionHostId={selectedRepoExecutionHostId}
+              projectId={selectedRepoProjectId}
+              value={parentWorktreeId}
+              onChange={onParentWorktreeIdChange}
+              activeFolderWorkspaceId={activeFolderWorkspaceId}
+              disabled={!advancedOpen}
+            />
+          ) : null}
+
           <div className="space-y-1">
             <label className="text-xs font-medium text-muted-foreground">
               {translate('auto.components.NewWorkspaceComposerCard.f8728aa4f9', 'Note')}
diff --git a/src/renderer/src/components/new-workspace/new-workspace-composer-card-props.ts b/src/renderer/src/components/new-workspace/new-workspace-composer-card-props.ts
index 52b70a8b9e0..bcff4c96f63 100644
--- a/src/renderer/src/components/new-workspace/new-workspace-composer-card-props.ts
+++ b/src/renderer/src/components/new-workspace/new-workspace-composer-card-props.ts
@@ -18,6 +18,7 @@ import type { SparsePreset } from '../../../../shared/worktree/create-types'
 import type { SshConnectionStatus } from '../../../../shared/ssh-types'
 import type { TaskSourceContext } from '../../../../shared/task-source-context'
 import type { TuiAgent } from '../../../../shared/tui-agent'
+import type { ExecutionHostId } from '../../../../shared/execution-host'
 
 export type RepoOption = React.ComponentProps<typeof RepoCombobox>['repos'][number]
 export type EphemeralVmRecipeOption = NonNullable<OrcaHooks['environmentRecipes']>[number]
@@ -61,6 +62,11 @@ export type NewWorkspaceComposerCardProps = {
   onNameValueChange: (value: string) => void
   branchNameOverride: string | undefined
   onBranchNameOverrideChange: (value: string | undefined) => void
+  parentWorktreeId?: string | null
+  onParentWorktreeIdChange?: (value: string | null) => void
+  selectedRepoExecutionHostId?: ExecutionHostId | null
+  selectedRepoProjectId?: string | null
+  activeFolderWorkspaceId?: string | null
   onSmartGitHubItemSelect: (item: GitHubWorkItem) => void
   onSmartGitLabItemSelect: (item: GitLabWorkItem) => void
   onSmartBranchSelect: (refName: string, localBranchName: string) => void
diff --git a/src/renderer/src/components/right-sidebar/folder-workspace-attached-worktrees.ts b/src/renderer/src/components/right-sidebar/folder-workspace-attached-worktrees.ts
index 577f21aa1f1..af18138b09d 100644
--- a/src/renderer/src/components/right-sidebar/folder-workspace-attached-worktrees.ts
+++ b/src/renderer/src/components/right-sidebar/folder-workspace-attached-worktrees.ts
@@ -131,7 +131,8 @@ function getWorktreeById(
   )
 }
 
-function getLineageChildWorktree(
+/** Exported so the composer's parent picker offers exactly the roots this view attaches. */
+export function getLineageChildWorktree(
   lineage: WorkspaceLineage,
   worktreeById: Map<string, Worktree>
 ): Worktree | null {
diff --git a/src/renderer/src/hooks/composer-state/composer-card-contract.ts b/src/renderer/src/hooks/composer-state/composer-card-contract.ts
index b41282032e4..1dffa161c32 100644
--- a/src/renderer/src/hooks/composer-state/composer-card-contract.ts
+++ b/src/renderer/src/hooks/composer-state/composer-card-contract.ts
@@ -14,6 +14,9 @@ export type ComposerCardSourceProps = Pick<
   | 'ephemeralVmRecipeError'
   | 'name'
   | 'branchNameOverride'
+  | 'parentWorktreeId'
+  | 'selectedRepoExecutionHostId'
+  | 'selectedRepoProjectId'
   | 'smartNameSelection'
   | 'reuseSelectedBranch'
   | 'createMultiple'
@@ -63,6 +66,7 @@ export type ComposerCardActionProps = {
   smartNameRepoSwitchTarget?: 'project' | 'task-source'
   onNameValueChange: ComposerModel['handleNameValueChange']
   onBranchNameOverrideChange: ComposerModel['handleBranchNameOverrideChange']
+  onParentWorktreeIdChange: ComposerModel['setParentWorktreeId']
   onSmartGitHubItemSelect: ComposerModel['handleSmartGitHubItemSelect']
   onSmartGitLabItemSelect: ComposerModel['handleSmartGitLabItemSelect']
   onSmartBranchSelect: ComposerModel['handleSmartBranchSelect']
diff --git a/src/renderer/src/hooks/composer-state/composer-card-props.ts b/src/renderer/src/hooks/composer-state/composer-card-props.ts
index 8363910fe8f..0e126e3af75 100644
--- a/src/renderer/src/hooks/composer-state/composer-card-props.ts
+++ b/src/renderer/src/hooks/composer-state/composer-card-props.ts
@@ -13,6 +13,7 @@ export function buildComposerCardProps(state: ComposerModel) {
     attachmentPaths,
     baseBranch,
     branchNameOverride,
+    parentWorktreeId,
     createGateMode,
     createError,
     createMultiple,
@@ -81,10 +82,12 @@ export function buildComposerCardProps(state: ComposerModel) {
     selectedProjectHostSetupId,
     selectedProjectId,
     selectedRepo,
+    selectedRepoExecutionHostId,
     selectedRepoConnectInProgress,
     selectedRepoConnectionId,
     selectedRepoGitHubSourceContext,
     selectedRepoIsGit,
+    selectedRepoProjectId,
     selectedRepoRequiresConnection,
     shouldWaitForIssueAutomationCheck,
     sourceIntentBlocksCreate,
@@ -96,6 +99,7 @@ export function buildComposerCardProps(state: ComposerModel) {
     setCreateMultiple,
     setLinkQuery,
     setNote,
+    setParentWorktreeId,
     setSelectedEphemeralVmRecipeId,
     setSetupDecision,
     setSmartNameMode,
@@ -157,6 +161,10 @@ export function buildComposerCardProps(state: ComposerModel) {
     onNameValueChange: handleNameValueChange,
     branchNameOverride: isProjectGroupTarget ? undefined : branchNameOverride,
     onBranchNameOverrideChange: isProjectGroupTarget ? () => {} : handleBranchNameOverrideChange,
+    parentWorktreeId: isProjectGroupTarget ? null : parentWorktreeId,
+    onParentWorktreeIdChange: isProjectGroupTarget ? () => {} : setParentWorktreeId,
+    selectedRepoExecutionHostId: isProjectGroupTarget ? null : selectedRepoExecutionHostId,
+    selectedRepoProjectId: isProjectGroupTarget ? null : selectedRepoProjectId,
     onSmartGitHubItemSelect: handleSmartGitHubItemSelect,
     onSmartGitLabItemSelect: handleSmartGitLabItemSelect,
     onSmartBranchSelect: isProjectGroupTarget ? () => {} : handleSmartBranchSelect,
diff --git a/src/renderer/src/hooks/composer-state/composer-store-actions.ts b/src/renderer/src/hooks/composer-state/composer-store-actions.ts
index 3c0a172dc46..3aa7d96f5d3 100644
--- a/src/renderer/src/hooks/composer-state/composer-store-actions.ts
+++ b/src/renderer/src/hooks/composer-state/composer-store-actions.ts
@@ -55,6 +55,7 @@ export type ComposerStoreActions = {
       linkedTaskSourceContext?: TaskSourceContext | null
       startupDraft?: string
       nameWasGenerated?: boolean
+      parentWorktreeId?: string
       provisionedRoot?: {
         runtimeId: string
         executionHostId: ExecutionHostId
diff --git a/src/renderer/src/hooks/composer-state/composer-submit-orchestration.ts b/src/renderer/src/hooks/composer-state/composer-submit-orchestration.ts
index e4289e452cb..b925eb12b2d 100644
--- a/src/renderer/src/hooks/composer-state/composer-submit-orchestration.ts
+++ b/src/renderer/src/hooks/composer-state/composer-submit-orchestration.ts
@@ -98,6 +98,7 @@ export function useComposerSubmitOrchestration(
     normalizedSparseDirectories: target.derivedComposerState.normalizedSparseDirectories,
     note: target.sourceContextState.note,
     onCreated: target.composerTargetStore.onCreated,
+    parentWorktreeId: target.workspaceIdentityState.parentWorktreeId,
     persistDraft: target.composerTargetStore.persistDraft,
     persistSetupAgentStartupPolicy: target.providerRuntimeSync.persistSetupAgentStartupPolicy,
     prepareFullSubmit: fullSubmitPreparation.prepareFullSubmit,
@@ -210,6 +211,7 @@ export function useComposerSubmitOrchestration(
     linkedGitLabMR: target.workspaceIdentityState.linkedGitLabMR,
     normalizedSparseDirectories: target.derivedComposerState.normalizedSparseDirectories,
     onCreated: target.composerTargetStore.onCreated,
+    parentWorktreeId: target.workspaceIdentityState.parentWorktreeId,
     persistDraft: target.composerTargetStore.persistDraft,
     persistSetupAgentStartupPolicy: target.providerRuntimeSync.persistSetupAgentStartupPolicy,
     prepareQuickSubmit: quickSubmitPreparation.prepareQuickSubmit,
diff --git a/src/renderer/src/hooks/composer-state/full-creation-execution.test.ts b/src/renderer/src/hooks/composer-state/full-creation-execution.test.ts
index 704dac2832e..c8bca80df09 100644
--- a/src/renderer/src/hooks/composer-state/full-creation-execution.test.ts
+++ b/src/renderer/src/hooks/composer-state/full-creation-execution.test.ts
@@ -72,6 +72,7 @@ describe('useFullCreationExecution cancellation', () => {
       normalizedSparseDirectories: [],
       note: '',
       onCreated: vi.fn<NonNullable<FullCreationExecutionInput['onCreated']>>(),
+      parentWorktreeId: null,
       persistDraft: false,
       persistSetupAgentStartupPolicy,
       prepareFullSubmit: vi
diff --git a/src/renderer/src/hooks/composer-state/full-creation-execution.ts b/src/renderer/src/hooks/composer-state/full-creation-execution.ts
index 713d42961d1..04ec3e2cf6d 100644
--- a/src/renderer/src/hooks/composer-state/full-creation-execution.ts
+++ b/src/renderer/src/hooks/composer-state/full-creation-execution.ts
@@ -12,6 +12,7 @@ export type FullCreationExecutionInput = Pick<
   | 'normalizedSparseDirectories'
   | 'note'
   | 'onCreated'
+  | 'parentWorktreeId'
   | 'persistDraft'
   | 'persistSetupAgentStartupPolicy'
   | 'prepareFullSubmit'
@@ -47,6 +48,7 @@ export function useFullCreationExecution(input: FullCreationExecutionInput) {
     normalizedSparseDirectories,
     note,
     onCreated,
+    parentWorktreeId,
     persistDraft,
     persistSetupAgentStartupPolicy,
     prepareFullSubmit,
@@ -155,7 +157,8 @@ export function useFullCreationExecution(input: FullCreationExecutionInput) {
           nameWasGenerated,
           ...(!backendStartup && startupPlan?.draftPrompt
             ? { startupDraft: startupPlan.draftPrompt }
-            : {})
+            : {}),
+          ...(parentWorktreeId ? { parentWorktreeId } : {})
         }
       )
 
@@ -251,6 +254,7 @@ export function useFullCreationExecution(input: FullCreationExecutionInput) {
       normalizedSparseDirectories,
       note,
       onCreated,
+      parentWorktreeId,
       persistDraft,
       persistSetupAgentStartupPolicy,
       prepareFullSubmit,
diff --git a/src/renderer/src/hooks/composer-state/identity-model.ts b/src/renderer/src/hooks/composer-state/identity-model.ts
index 8830e3d72bc..e375dd754d7 100644
--- a/src/renderer/src/hooks/composer-state/identity-model.ts
+++ b/src/renderer/src/hooks/composer-state/identity-model.ts
@@ -18,6 +18,8 @@ export type ComposerIdentityModel = {
   setCompareBaseRef: React.Dispatch<React.SetStateAction<string | undefined>>
   branchNameOverride: string | undefined
   setBranchNameOverride: React.Dispatch<React.SetStateAction<string | undefined>>
+  parentWorktreeId: string | null
+  setParentWorktreeId: React.Dispatch<React.SetStateAction<string | null>>
   branchNameOverridePreservesNameEdits: boolean
   setBranchNameOverridePreservesNameEdits: React.Dispatch<React.SetStateAction<boolean>>
   smartNameMode: SmartNameMode
diff --git a/src/renderer/src/hooks/composer-state/quick-creation-execution.ts b/src/renderer/src/hooks/composer-state/quick-creation-execution.ts
index 1e91f686d82..b6b14350290 100644
--- a/src/renderer/src/hooks/composer-state/quick-creation-execution.ts
+++ b/src/renderer/src/hooks/composer-state/quick-creation-execution.ts
@@ -12,6 +12,7 @@ type QuickCreationExecutionInput = Pick<
   | 'linkedGitLabMR'
   | 'normalizedSparseDirectories'
   | 'onCreated'
+  | 'parentWorktreeId'
   | 'persistDraft'
   | 'persistSetupAgentStartupPolicy'
   | 'prepareQuickSubmit'
@@ -58,6 +59,7 @@ export function useQuickCreationExecution(input: QuickCreationExecutionInput) {
     linkedGitLabMR,
     normalizedSparseDirectories,
     onCreated,
+    parentWorktreeId,
     persistDraft,
     persistSetupAgentStartupPolicy,
     prepareQuickSubmit,
@@ -217,6 +219,7 @@ export function useQuickCreationExecution(input: QuickCreationExecutionInput) {
         linkedLinearIssueWorkspaceId,
         linkedLinearIssueOrganizationUrlKey,
         branchNameOverride: effectiveBranchNameOverride,
+        parentWorktreeId,
         workspaceStatus: resolvedInitialWorkspaceStatus,
         linkedGitLabMR,
         linkedGitLabIssue,
@@ -259,6 +262,7 @@ export function useQuickCreationExecution(input: QuickCreationExecutionInput) {
       linkedGitLabMR,
       normalizedSparseDirectories,
       onCreated,
+      parentWorktreeId,
       persistDraft,
       persistSetupAgentStartupPolicy,
       prepareQuickSubmit,
diff --git a/src/renderer/src/hooks/composer-state/quick-creation-request.test.ts b/src/renderer/src/hooks/composer-state/quick-creation-request.test.ts
index 0533bcc2e28..d5cd9a11c5b 100644
--- a/src/renderer/src/hooks/composer-state/quick-creation-request.test.ts
+++ b/src/renderer/src/hooks/composer-state/quick-creation-request.test.ts
@@ -29,6 +29,7 @@ function createInput(
     linkedLinearIssueWorkspaceId: undefined,
     linkedLinearIssueOrganizationUrlKey: undefined,
     branchNameOverride: undefined,
+    parentWorktreeId: null,
     workspaceStatus: undefined,
     linkedGitLabMR: null,
     linkedGitLabIssue: null,
@@ -87,6 +88,7 @@ describe('quick composer creation request', () => {
         linkedLinearIssueWorkspaceId: 'workspace-1',
         linkedLinearIssueOrganizationUrlKey: 'orca',
         branchNameOverride: 'feature',
+        parentWorktreeId: 'repo-1::/worktrees/parent',
         workspaceStatus: 'in-progress',
         linkedGitLabMR: 9,
         linkedGitLabIssue: 8,
@@ -107,6 +109,7 @@ describe('quick composer creation request', () => {
       linkedGitLabMR: 9,
       linkedGitLabIssue: 8,
       branchNameOverride: 'feature',
+      parentWorktreeId: 'repo-1::/worktrees/parent',
       launchDraftPrompt: 'draft',
       suppressTerminalFocusOnCompletion: true
     })
diff --git a/src/renderer/src/hooks/composer-state/quick-creation-request.ts b/src/renderer/src/hooks/composer-state/quick-creation-request.ts
index 71f0735f70b..e12f2dd6256 100644
--- a/src/renderer/src/hooks/composer-state/quick-creation-request.ts
+++ b/src/renderer/src/hooks/composer-state/quick-creation-request.ts
@@ -33,6 +33,7 @@ export type QuickCreationRequestInput = {
   linkedLinearIssueWorkspaceId: string | undefined
   linkedLinearIssueOrganizationUrlKey: string | undefined
   branchNameOverride: string | undefined
+  parentWorktreeId: string | null
   workspaceStatus: WorktreeCreationRequest['workspaceStatus']
   linkedGitLabMR: number | null
   linkedGitLabIssue: number | null
@@ -88,6 +89,7 @@ export function buildQuickCreationRequest(
       ? { linkedLinearIssueOrganizationUrlKey: input.linkedLinearIssueOrganizationUrlKey }
       : {}),
     ...(input.branchNameOverride ? { branchNameOverride: input.branchNameOverride } : {}),
+    ...(input.parentWorktreeId ? { parentWorktreeId: input.parentWorktreeId } : {}),
     ...(input.workspaceStatus ? { workspaceStatus: input.workspaceStatus } : {}),
     ...(input.includeGitLabLinks && input.linkedGitLabMR != null
       ? { linkedGitLabMR: input.linkedGitLabMR }
diff --git a/src/renderer/src/hooks/composer-state/workspace-identity-state.ts b/src/renderer/src/hooks/composer-state/workspace-identity-state.ts
index 8d46a3551d4..6b7e73e9417 100644
--- a/src/renderer/src/hooks/composer-state/workspace-identity-state.ts
+++ b/src/renderer/src/hooks/composer-state/workspace-identity-state.ts
@@ -100,6 +100,8 @@ export function useWorkspaceIdentityState(input: WorkspaceIdentityStateInput) {
     initialLinearBranchName
   )
 
+  const [parentWorktreeId, setParentWorktreeId] = useState<string | null>(null)
+
   const [branchNameOverridePreservesNameEdits, setBranchNameOverridePreservesNameEdits] = useState(
     Boolean(initialLinearBranchName)
   )
@@ -195,6 +197,8 @@ export function useWorkspaceIdentityState(input: WorkspaceIdentityStateInput) {
     setCompareBaseRef,
     branchNameOverride,
     setBranchNameOverride,
+    parentWorktreeId,
+    setParentWorktreeId,
     branchNameOverridePreservesNameEdits,
     setBranchNameOverridePreservesNameEdits,
     smartNameMode,
diff --git a/src/renderer/src/hooks/useComposerState.integration.test.ts b/src/renderer/src/hooks/useComposerState.integration.test.ts
index 2119e99f860..c82e1a118c6 100644
--- a/src/renderer/src/hooks/useComposerState.integration.test.ts
+++ b/src/renderer/src/hooks/useComposerState.integration.test.ts
@@ -1,6 +1,6 @@
 // @vitest-environment happy-dom
 
-import { renderHook } from '@testing-library/react'
+import { act, renderHook } from '@testing-library/react'
 import { afterEach, beforeEach, describe, expect, it, vi } from 'vitest'
 import { useAppStore } from '@/store'
 import { useComposerState } from './useComposerState'
@@ -31,7 +31,7 @@ afterEach(() => {
 })
 
 describe('useComposerState integrated lifecycle', () => {
-  it('composes two live composers and releases each native drop listener on unmount', () => {
+  it('composes two live composers and exposes the parent-worktree control state', () => {
     useAppStore.setState({
       repos: [],
       projects: [],
@@ -57,6 +57,10 @@ describe('useComposerState integrated lifecycle', () => {
 
     expect(first.result.current.cardProps.name).toBe('first')
     expect(second.result.current.cardProps.name).toBe('second')
+    expect(first.result.current.cardProps.parentWorktreeId).toBeNull()
+    expect(first.result.current.cardProps.onParentWorktreeIdChange).toBeTypeOf('function')
+    act(() => first.result.current.cardProps.onParentWorktreeIdChange('repo-1::/parent'))
+    expect(first.result.current.cardProps.parentWorktreeId).toBe('repo-1::/parent')
     expect(window.api.ui.onFileDrop).toHaveBeenCalledTimes(2)
 
     second.unmount()
diff --git a/src/renderer/src/i18n/locales/en.json b/src/renderer/src/i18n/locales/en.json
index a27cd89629c..06989bb3f9e 100644
--- a/src/renderer/src/i18n/locales/en.json
+++ b/src/renderer/src/i18n/locales/en.json
@@ -448,7 +448,10 @@
                 }
               }
             }
-          }
+          },
+          "createdWithoutParentNesting": "Created without nesting under \"{{value0}}\"",
+          "createdWithoutParentNestingUnnamed": "Created without nesting under the selected parent",
+          "createdWithoutParentNestingDetail": "The parent workspace was no longer available. You can set it from the workspace menu."
         },
         "repos": {
           "2975400634": "Update Orca server to open non-Git folders on this runtime.",
@@ -16305,6 +16308,13 @@
         "remoteLabel": "Browsers on {{value0}}",
         "clientNoteLocalStorage": "Imports read this device’s browsers. Cookies are stored locally.",
         "remoteNoteRemoteStorage": "Imports read browsers on {{value0}}. Cookies are stored on that machine, and a permission prompt may appear on its screen."
+      },
+      "ComposerParentWorktreePicker": {
+        "label": "Parent worktree",
+        "noParent": "No parent",
+        "description": "Nests this workspace under another in the sidebar. Does not change the base branch.",
+        "searchPlaceholder": "Search workspaces...",
+        "noMatches": "No matches."
       }
     },
     "i18n": {
diff --git a/src/renderer/src/i18n/locales/es.json b/src/renderer/src/i18n/locales/es.json
index 8b014a386da..69e7c383533 100644
--- a/src/renderer/src/i18n/locales/es.json
+++ b/src/renderer/src/i18n/locales/es.json
@@ -263,7 +263,10 @@
           "3b57982bf6": "Git no pudo eliminar de forma segura la rama \"{{value0}}\" después de eliminar el espacio de trabajo \"{{value1}}\", así que Orca la conservó para evitar perder commits locales.",
           "81f13f48d2": "Git no pudo eliminar de forma segura la rama \"{{value0}}\" después de eliminar el worktree \"{{value1}}\", así que Orca la conservó para evitar perder commits locales.",
           "runtimeScopeForbiddenTitle": "Esta conexión tiene acceso limitado (móvil)",
-          "runtimeScopeForbiddenDescription": "Los espacios de trabajo no están disponibles con un emparejamiento de acceso móvil. Vuelve a conectarte con el enlace del navegador desde Ajustes → Servidores remotos de Orca → Comparte este servidor Orca."
+          "runtimeScopeForbiddenDescription": "Los espacios de trabajo no están disponibles con un emparejamiento de acceso móvil. Vuelve a conectarte con el enlace del navegador desde Ajustes → Servidores remotos de Orca → Comparte este servidor Orca.",
+          "createdWithoutParentNesting": "Creado sin anidarlo bajo \"{{value0}}\"",
+          "createdWithoutParentNestingUnnamed": "Creado sin anidarlo bajo el worktree padre seleccionado",
+          "createdWithoutParentNestingDetail": "El espacio de trabajo padre ya no estaba disponible. Puedes establecerlo desde el menú del espacio de trabajo."
         },
         "repos": {
           "2975400634": "Actualiza el servidor Orca para abrir carpetas que no sean Git en este host.",
@@ -14433,6 +14436,13 @@
           "deleteDescription": "“{{name}}” ya no estará disponible en su enlace público.",
           "delete": "Eliminar"
         }
+      },
+      "ComposerParentWorktreePicker": {
+        "label": "Worktree padre",
+        "noParent": "Sin worktree padre",
+        "description": "Anida este espacio de trabajo bajo otro en la barra lateral. No cambia la rama base.",
+        "searchPlaceholder": "Buscar espacios de trabajo...",
+        "noMatches": "No hay coincidencias."
       }
     },
     "i18n": {
diff --git a/src/renderer/src/i18n/locales/ja.json b/src/renderer/src/i18n/locales/ja.json
index 0e5e5fd0e9d..43129d595af 100644
--- a/src/renderer/src/i18n/locales/ja.json
+++ b/src/renderer/src/i18n/locales/ja.json
@@ -263,7 +263,10 @@
           "3b57982bf6": "ワークスペース\"{{value1}}\"を削除した後、Git はブランチ\"{{value0}}\"を安全に削除できなかったため、Orca はローカルコミットを失わないように保持しました。",
           "81f13f48d2": "ワークツリー\"{{value1}}\"を削除した後、Git はブランチ\"{{value0}}\"を安全に削除できなかったため、Orca はローカルコミットを失わないように保持しました。",
           "runtimeScopeForbiddenTitle": "この接続は制限付き（モバイル）アクセスです",
-          "runtimeScopeForbiddenDescription": "モバイル向けペアリングではワークスペースを使用できません。[設定] → [リモート Orca サーバー] → [この Orca サーバーを共有する] から、ブラウザ用リンクで再接続してください。"
+          "runtimeScopeForbiddenDescription": "モバイル向けペアリングではワークスペースを使用できません。[設定] → [リモート Orca サーバー] → [この Orca サーバーを共有する] から、ブラウザ用リンクで再接続してください。",
+          "createdWithoutParentNesting": "「{{value0}}」の配下にネストせずに作成しました",
+          "createdWithoutParentNestingUnnamed": "選択した親ワークツリーの配下にネストせずに作成しました",
+          "createdWithoutParentNestingDetail": "親ワークスペースは利用できなくなりました。ワークスペースメニューから設定できます。"
         },
         "repos": {
           "2975400634": "Orca サーバーを更新して、このランタイムで Git 以外のフォルダーを開くようにします。",
@@ -14424,6 +14427,13 @@
           "deleteDescription": "「{{name}}」は公開リンクで利用できなくなります。",
           "delete": "削除"
         }
+      },
+      "ComposerParentWorktreePicker": {
+        "label": "親ワークツリー",
+        "noParent": "親なし",
+        "description": "このワークスペースをサイドバー内の別のワークスペースの配下にネストします。ベースブランチは変更されません。",
+        "searchPlaceholder": "ワークスペースを検索...",
+        "noMatches": "一致する項目がありません。"
       }
     },
     "i18n": {
diff --git a/src/renderer/src/i18n/locales/ko.json b/src/renderer/src/i18n/locales/ko.json
index a36f0c50c7f..e88670171ac 100644
--- a/src/renderer/src/i18n/locales/ko.json
+++ b/src/renderer/src/i18n/locales/ko.json
@@ -266,7 +266,10 @@
           "3b57982bf6": "\"{{value1}}\" 워크스페이스를 삭제한 후 Git이 \"{{value0}}\" 브랜치를 안전하게 삭제할 수 없어 Orca가 로컬 커밋 손실을 방지하기 위해 유지했습니다.",
           "81f13f48d2": "\"{{value1}}\" 워크트리를 삭제한 후 Git이 \"{{value0}}\" 브랜치를 안전하게 삭제할 수 없어 Orca가 로컬 커밋 손실을 방지하기 위해 유지했습니다.",
           "runtimeScopeForbiddenTitle": "이 연결은 제한된(모바일) 액세스입니다",
-          "runtimeScopeForbiddenDescription": "모바일 범위 페어링에서는 워크스페이스를 사용할 수 없습니다. 설정 → 원격 Orca 서버 → 이 Orca 서버 공유에서 브라우저 액세스 링크로 다시 연결하세요."
+          "runtimeScopeForbiddenDescription": "모바일 범위 페어링에서는 워크스페이스를 사용할 수 없습니다. 설정 → 원격 Orca 서버 → 이 Orca 서버 공유에서 브라우저 액세스 링크로 다시 연결하세요.",
+          "createdWithoutParentNesting": "\"{{value0}}\" 아래에 중첩하지 않고 생성했습니다",
+          "createdWithoutParentNestingUnnamed": "선택한 상위 워크트리 아래에 중첩하지 않고 생성했습니다",
+          "createdWithoutParentNestingDetail": "상위 워크스페이스를 더 이상 사용할 수 없습니다. 워크스페이스 메뉴에서 설정할 수 있습니다."
         },
         "repos": {
           "2975400634": "이 런타임에서 Git이 아닌 폴더를 열려면 Orca 서버를 업데이트하세요.",
@@ -3879,17 +3882,82 @@
       },
       "skills": {
         "SkillsPage": {
-          "cb142070b4": "새로 고침", "a68dee6a32": "스킬 검색", "f43ad6edf3": "스킬", "ea72d6185b": "스킬을 검색하지 못했습니다", "dc4c3328ee": "파일 표시", "9963dff6d3": "설명을 찾을 수 없습니다.", "995fde8337": "스킬 파일을 표시하지 못했습니다", "4acd6d68ec": "스킬을 찾을 수 없습니다", "6a62a0168c": "일치하는 항목 없음", "08a321a984": "현재 검색 및 필터와 일치하는 스킬이 없습니다.", "cd7893fbc1": "스킬 검색 중", "35b9a724a0": "사용 가능", "c13b82793c": "설치 관리", "aee7b99cc6": "링크에서 설치", "filterProvider": "에이전트별 필터", "filterSource": "소스별 필터", "allSources": "전체", "clearFilters": "필터 지우기", "closeSkills": "스킬 닫기", "closeTooltip": "닫기 · Esc", "moreActions": "추가 작업", "sharedLinks": "공유 링크", "emptyCopy": "검색한 스킬 폴더가 비어 있습니다. 공유 번들을 설치하거나 스킬을 추가한 후 새로 고치세요.", "retry": "다시 시도", "remoteShareNotice": "이 스킬은 {{host}}에 있습니다. 공유하려면 해당 머신에서 스킬을 여세요.", "viewSwitch": "표시", "searchLinks": "링크 검색", "deleteSkills": "스킬 삭제…"
+          "cb142070b4": "새로 고침",
+          "a68dee6a32": "스킬 검색",
+          "f43ad6edf3": "스킬",
+          "ea72d6185b": "스킬을 검색하지 못했습니다",
+          "dc4c3328ee": "파일 표시",
+          "9963dff6d3": "설명을 찾을 수 없습니다.",
+          "995fde8337": "스킬 파일을 표시하지 못했습니다",
+          "4acd6d68ec": "스킬을 찾을 수 없습니다",
+          "6a62a0168c": "일치하는 항목 없음",
+          "08a321a984": "현재 검색 및 필터와 일치하는 스킬이 없습니다.",
+          "cd7893fbc1": "스킬 검색 중",
+          "35b9a724a0": "사용 가능",
+          "c13b82793c": "설치 관리",
+          "aee7b99cc6": "링크에서 설치",
+          "filterProvider": "에이전트별 필터",
+          "filterSource": "소스별 필터",
+          "allSources": "전체",
+          "clearFilters": "필터 지우기",
+          "closeSkills": "스킬 닫기",
+          "closeTooltip": "닫기 · Esc",
+          "moreActions": "추가 작업",
+          "sharedLinks": "공유 링크",
+          "emptyCopy": "검색한 스킬 폴더가 비어 있습니다. 공유 번들을 설치하거나 스킬을 추가한 후 새로 고치세요.",
+          "retry": "다시 시도",
+          "remoteShareNotice": "이 스킬은 {{host}}에 있습니다. 공유하려면 해당 머신에서 스킬을 여세요.",
+          "viewSwitch": "표시",
+          "searchLinks": "링크 검색",
+          "deleteSkills": "스킬 삭제…"
         },
         "SkillShareSelectionControls": { "01c5a15e02": "스킬 공유" },
-        "SkillRow": { "updatedUnknown": "날짜 없음", "pathCopied": "경로 복사됨", "copyPath": "경로 복사", "detailPath": "경로", "skillActions": "{{value0}} 작업", "viewDetails": "세부 정보 보기", "deleteSkill": "삭제…" },
+        "SkillRow": {
+          "updatedUnknown": "날짜 없음",
+          "pathCopied": "경로 복사됨",
+          "copyPath": "경로 복사",
+          "detailPath": "경로",
+          "skillActions": "{{value0}} 작업",
+          "viewDetails": "세부 정보 보기",
+          "deleteSkill": "삭제…"
+        },
         "SkillsList": { "listLabel": "스킬" },
-        "sourceStatus": { "missing": "폴더를 찾을 수 없음", "remoteRepo": "원격 리포지토리 — 검색 안 됨", "unavailable": "검색 안 됨" },
+        "sourceStatus": {
+          "missing": "폴더를 찾을 수 없음",
+          "remoteRepo": "원격 리포지토리 — 검색 안 됨",
+          "unavailable": "검색 안 됨"
+        },
         "sources": { "heading": "스킬 폴더" },
-        "sourceKind": { "home": "홈", "workspace": "워크스페이스", "bundled": "번들", "plugin": "플러그인" },
-        "count": { "skillOne": "스킬 {{count}}개", "skillOther": "스킬 {{count}}개", "sourceOne": "소스 {{count}}개", "sourceOther": "소스 {{count}}개", "fileOne": "파일 {{count}}개", "fileOther": "파일 {{count}}개", "resultOne": "결과 {{count}}개", "resultOther": "결과 {{count}}개", "selected": "{{count}}개 선택됨", "shareOne": "스킬 {{count}}개 공유", "shareOther": "스킬 {{count}}개 공유", "linkOne": "링크 {{count}}개", "linkOther": "링크 {{count}}개" },
+        "sourceKind": {
+          "home": "홈",
+          "workspace": "워크스페이스",
+          "bundled": "번들",
+          "plugin": "플러그인"
+        },
+        "count": {
+          "skillOne": "스킬 {{count}}개",
+          "skillOther": "스킬 {{count}}개",
+          "sourceOne": "소스 {{count}}개",
+          "sourceOther": "소스 {{count}}개",
+          "fileOne": "파일 {{count}}개",
+          "fileOther": "파일 {{count}}개",
+          "resultOne": "결과 {{count}}개",
+          "resultOther": "결과 {{count}}개",
+          "selected": "{{count}}개 선택됨",
+          "shareOne": "스킬 {{count}}개 공유",
+          "shareOther": "스킬 {{count}}개 공유",
+          "linkOne": "링크 {{count}}개",
+          "linkOther": "링크 {{count}}개"
+        },
         "filter": { "allAgents": "모든 에이전트", "sharedAgent": "공유됨 (.agents)" },
-        "SkillsSelectionHeader": { "exit": "선택 나가기", "exitTooltip": "선택 나가기 · Esc", "title": "공유할 스킬 선택", "selectAll": "가능한 {{count}}개 모두 선택", "clear": "지우기", "deleteTitle": "삭제할 스킬 선택" },
+        "SkillsSelectionHeader": {
+          "exit": "선택 나가기",
+          "exitTooltip": "선택 나가기 · Esc",
+          "title": "공유할 스킬 선택",
+          "selectAll": "가능한 {{count}}개 모두 선택",
+          "clear": "지우기",
+          "deleteTitle": "삭제할 스킬 선택"
+        },
         "SkillDetailDialog": { "agents": "에이전트", "updated": "업데이트됨", "copy": "복사" },
         "SkillFreshnessNudge": {
           "titleOne": "설치된 Orca 스킬이 오래되었습니다",
@@ -14391,6 +14459,13 @@
           "deleteDescription": "“{{name}}”은(는) 공개 링크에서 더 이상 사용할 수 없습니다.",
           "delete": "삭제"
         }
+      },
+      "ComposerParentWorktreePicker": {
+        "label": "상위 워크트리",
+        "noParent": "상위 워크트리 없음",
+        "description": "이 워크스페이스를 사이드바의 다른 워크스페이스 아래에 중첩합니다. 기준 브랜치는 변경되지 않습니다.",
+        "searchPlaceholder": "워크스페이스 검색...",
+        "noMatches": "일치하는 항목이 없습니다."
       }
     },
     "i18n": {
diff --git a/src/renderer/src/i18n/locales/zh.json b/src/renderer/src/i18n/locales/zh.json
index 5b55818c67d..00f5e077a07 100644
--- a/src/renderer/src/i18n/locales/zh.json
+++ b/src/renderer/src/i18n/locales/zh.json
@@ -266,7 +266,10 @@
           "3b57982bf6": "删除工作区\"{{value1}}\"后，Git 无法安全删除分支\"{{value0}}\"，因此 Orca 将其保留以避免丢失本地提交。",
           "81f13f48d2": "删除工作树\"{{value1}}\"后，Git 无法安全删除分支\"{{value0}}\"，因此 Orca 将其保留以避免丢失本地提交。",
           "runtimeScopeForbiddenTitle": "此连接具有受限（移动端）访问权限",
-          "runtimeScopeForbiddenDescription": "移动端范围的配对无法使用工作区。请通过设置 → 远程 Orca 服务器 → 分享此 Orca 服务器中的浏览器访问链接重新连接。"
+          "runtimeScopeForbiddenDescription": "移动端范围的配对无法使用工作区。请通过设置 → 远程 Orca 服务器 → 分享此 Orca 服务器中的浏览器访问链接重新连接。",
+          "createdWithoutParentNesting": "已创建，但未嵌套在“{{value0}}”下",
+          "createdWithoutParentNestingUnnamed": "已创建，但未嵌套在所选父工作树下",
+          "createdWithoutParentNestingDetail": "父工作区已不可用。您可以从工作区菜单中重新设置。"
         },
         "repos": {
           "2975400634": "请更新 Orca 服务器，以便在此运行时打开非 Git 文件夹。",
@@ -3889,17 +3892,90 @@
       },
       "skills": {
         "SkillsPage": {
-          "cb142070b4": "刷新", "a68dee6a32": "搜索技能", "f43ad6edf3": "技能", "ea72d6185b": "无法扫描技能", "dc4c3328ee": "显示文件", "9963dff6d3": "未找到说明。", "995fde8337": "无法显示技能文件", "4acd6d68ec": "未找到技能", "6a62a0168c": "无匹配项", "08a321a984": "没有技能匹配当前搜索和筛选条件。", "cd7893fbc1": "正在扫描技能", "35b9a724a0": "可用", "c13b82793c": "管理安装", "aee7b99cc6": "从链接安装", "filterProvider": "按 Agent 筛选", "filterSource": "按来源筛选", "allSources": "全部", "clearFilters": "清除筛选", "closeSkills": "关闭技能", "closeTooltip": "关闭 · Esc", "moreActions": "更多操作", "sharedLinks": "共享链接", "emptyCopy": "扫描的技能文件夹为空。请安装共享包，或添加技能后刷新。", "retry": "重试", "remoteShareNotice": "这些技能位于 {{host}}。请在该机器上打开“技能”以进行共享。", "viewSwitch": "显示", "searchLinks": "搜索链接", "deleteSkills": "删除技能…"
+          "cb142070b4": "刷新",
+          "a68dee6a32": "搜索技能",
+          "f43ad6edf3": "技能",
+          "ea72d6185b": "无法扫描技能",
+          "dc4c3328ee": "显示文件",
+          "9963dff6d3": "未找到说明。",
+          "995fde8337": "无法显示技能文件",
+          "4acd6d68ec": "未找到技能",
+          "6a62a0168c": "无匹配项",
+          "08a321a984": "没有技能匹配当前搜索和筛选条件。",
+          "cd7893fbc1": "正在扫描技能",
+          "35b9a724a0": "可用",
+          "c13b82793c": "管理安装",
+          "aee7b99cc6": "从链接安装",
+          "filterProvider": "按 Agent 筛选",
+          "filterSource": "按来源筛选",
+          "allSources": "全部",
+          "clearFilters": "清除筛选",
+          "closeSkills": "关闭技能",
+          "closeTooltip": "关闭 · Esc",
+          "moreActions": "更多操作",
+          "sharedLinks": "共享链接",
+          "emptyCopy": "扫描的技能文件夹为空。请安装共享包，或添加技能后刷新。",
+          "retry": "重试",
+          "remoteShareNotice": "这些技能位于 {{host}}。请在该机器上打开“技能”以进行共享。",
+          "viewSwitch": "显示",
+          "searchLinks": "搜索链接",
+          "deleteSkills": "删除技能…"
         },
         "SkillShareSelectionControls": { "01c5a15e02": "共享技能" },
-        "SkillRow": { "updatedUnknown": "无日期", "pathCopied": "路径已复制", "copyPath": "复制路径", "detailPath": "路径", "skillActions": "{{value0}} 的操作", "viewDetails": "查看详情", "deleteSkill": "删除…" },
+        "SkillRow": {
+          "updatedUnknown": "无日期",
+          "pathCopied": "路径已复制",
+          "copyPath": "复制路径",
+          "detailPath": "路径",
+          "skillActions": "{{value0}} 的操作",
+          "viewDetails": "查看详情",
+          "deleteSkill": "删除…"
+        },
         "SkillsList": { "listLabel": "技能" },
-        "sourceStatus": { "missing": "未找到文件夹", "remoteRepo": "远程仓库 — 未扫描", "unavailable": "未扫描" },
+        "sourceStatus": {
+          "missing": "未找到文件夹",
+          "remoteRepo": "远程仓库 — 未扫描",
+          "unavailable": "未扫描"
+        },
         "sources": { "heading": "技能文件夹" },
-        "sourceKind": { "home": "主目录", "workspace": "工作区", "bundled": "内置", "plugin": "插件" },
-        "count": { "skillOne": "{{count}} 个技能", "skillOther": "{{count}} 个技能", "sourceOne": "{{count}} 个来源", "sourceOther": "{{count}} 个来源", "fileOne": "{{count}} 个文件", "fileOther": "{{count}} 个文件", "resultOne": "{{count}} 个结果", "resultOther": "{{count}} 个结果", "selected": "已选择 {{count}} 个", "shareOne": "共享 {{count}} 个技能", "shareOther": "共享 {{count}} 个技能", "linkOne": "{{count}} 个链接", "linkOther": "{{count}} 个链接", "deleteOne": "删除 {{count}} 个技能", "deleteOther": "删除 {{count}} 个技能", "deletedOne": "已删除 {{count}} 个技能", "deletedOther": "已删除 {{count}} 个技能", "deleteFolderOne": "{{count}} 个文件夹", "deleteFolderOther": "{{count}} 个文件夹", "deleteLinkOne": "{{count}} 个链接", "deleteLinkOther": "{{count}} 个链接" },
+        "sourceKind": {
+          "home": "主目录",
+          "workspace": "工作区",
+          "bundled": "内置",
+          "plugin": "插件"
+        },
+        "count": {
+          "skillOne": "{{count}} 个技能",
+          "skillOther": "{{count}} 个技能",
+          "sourceOne": "{{count}} 个来源",
+          "sourceOther": "{{count}} 个来源",
+          "fileOne": "{{count}} 个文件",
+          "fileOther": "{{count}} 个文件",
+          "resultOne": "{{count}} 个结果",
+          "resultOther": "{{count}} 个结果",
+          "selected": "已选择 {{count}} 个",
+          "shareOne": "共享 {{count}} 个技能",
+          "shareOther": "共享 {{count}} 个技能",
+          "linkOne": "{{count}} 个链接",
+          "linkOther": "{{count}} 个链接",
+          "deleteOne": "删除 {{count}} 个技能",
+          "deleteOther": "删除 {{count}} 个技能",
+          "deletedOne": "已删除 {{count}} 个技能",
+          "deletedOther": "已删除 {{count}} 个技能",
+          "deleteFolderOne": "{{count}} 个文件夹",
+          "deleteFolderOther": "{{count}} 个文件夹",
+          "deleteLinkOne": "{{count}} 个链接",
+          "deleteLinkOther": "{{count}} 个链接"
+        },
         "filter": { "allAgents": "所有 Agent", "sharedAgent": "共享 (.agents)" },
-        "SkillsSelectionHeader": { "exit": "退出选择", "exitTooltip": "退出选择 · Esc", "title": "选择要共享的技能", "selectAll": "选择全部 {{count}} 个符合条件的项目", "clear": "清除", "deleteTitle": "选择要删除的技能" },
+        "SkillsSelectionHeader": {
+          "exit": "退出选择",
+          "exitTooltip": "退出选择 · Esc",
+          "title": "选择要共享的技能",
+          "selectAll": "选择全部 {{count}} 个符合条件的项目",
+          "clear": "清除",
+          "deleteTitle": "选择要删除的技能"
+        },
         "SkillDetailDialog": { "agents": "Agent", "updated": "已更新", "copy": "复制" },
         "SkillFreshnessNudge": {
           "titleOne": "已安装的 Orca 技能已过期",
@@ -14407,6 +14483,13 @@
           "deleteDescription": "“{{name}}” 将无法再通过其公共链接访问。",
           "delete": "删除"
         }
+      },
+      "ComposerParentWorktreePicker": {
+        "label": "父工作树",
+        "noParent": "无父工作树",
+        "description": "在侧边栏中将此工作区嵌套到另一个工作区下。不会更改基础分支。",
+        "searchPlaceholder": "搜索工作区...",
+        "noMatches": "无匹配项。"
       }
     },
     "i18n": {
diff --git a/src/renderer/src/lib/pending-worktree-creation.ts b/src/renderer/src/lib/pending-worktree-creation.ts
index 42ec2f2c392..77f4db70744 100644
--- a/src/renderer/src/lib/pending-worktree-creation.ts
+++ b/src/renderer/src/lib/pending-worktree-creation.ts
@@ -79,6 +79,8 @@ export type WorktreeCreationRequest = {
   linkedLinearIssueWorkspaceId?: string | null
   linkedLinearIssueOrganizationUrlKey?: string | null
   branchNameOverride?: string
+  /** Parent picked in the composer's Advanced drawer. Sidebar nesting only, no git effect. */
+  parentWorktreeId?: string
   workspaceStatus?: WorkspaceStatus
   linkedGitLabMR?: number
   linkedGitLabIssue?: number
diff --git a/src/renderer/src/lib/worktree-creation-flow-agent-trust-preflight.test.ts b/src/renderer/src/lib/worktree-creation-flow-agent-trust-preflight.test.ts
index 928c3dfc87f..2431315509a 100644
--- a/src/renderer/src/lib/worktree-creation-flow-agent-trust-preflight.test.ts
+++ b/src/renderer/src/lib/worktree-creation-flow-agent-trust-preflight.test.ts
@@ -2,7 +2,7 @@ import { readFileSync } from 'node:fs'
 import { join } from 'node:path'
 import { describe, expect, it } from 'vitest'
 
-const FLOW_SOURCE = readFileSync(join(__dirname, 'worktree-creation-flow.ts'), 'utf8')
+const FLOW_SOURCE = readFileSync(join(__dirname, 'worktree-creation-flow-execute.ts'), 'utf8')
 
 function sourceBetween(source: string, startPattern: string, endPattern: string): string {
   const start = source.indexOf(startPattern)
diff --git a/src/renderer/src/lib/worktree-creation-flow-execute.ts b/src/renderer/src/lib/worktree-creation-flow-execute.ts
new file mode 100644
index 00000000000..03232b39526
--- /dev/null
+++ b/src/renderer/src/lib/worktree-creation-flow-execute.ts
@@ -0,0 +1,240 @@
+import { toast } from 'sonner'
+import { useAppStore } from '@/store'
+import { TUI_AGENT_CONFIG } from '../../../shared/tui-agent-config'
+import { activateAndRevealWorktree, type ActivateAndRevealResult } from '@/lib/worktree-activation'
+import { ensureWorktreeHasInitialTerminal } from '@/lib/worktree-initial-terminal-seeding'
+import { ensureAgentStartupInTerminal } from '@/lib/new-workspace'
+import { queueWorkspaceActivationTerminalFocus } from '@/lib/workspace-activation-terminal-focus'
+import {
+  attachEphemeralVmRuntimeToWorkspace,
+  cleanupEphemeralVmRuntimeForFailedCreate,
+  prepareRequestForCreate
+} from '@/lib/ephemeral-vm-worktree-creation'
+import { getProvisionedRootCreateOptions } from '@/lib/provisioned-root-create-options'
+import {
+  formatWorkspaceCreateError,
+  getWorkspaceCreateErrorToastMessage
+} from '@/lib/workspace-create-error-format'
+import type { CreateWorktreeResult } from '../../../shared/worktree/create-types'
+import type { WorktreeCreationRequest } from '@/lib/pending-worktree-creation'
+import { createBrowserUuid } from '@/lib/browser-uuid'
+import { seedAgentTabStateAfterWorktreeCreate } from '@/lib/worktree-creation-agent-seeds'
+import { resolveBackendDraftStartup } from '@/lib/worktree-draft-startup-view-mode'
+import { buildWorktreeCreationStartupOpt } from '@/lib/worktree-creation-flow-startup'
+
+// Why: activePendingCreationId can outlive the terminal route when the user
+// switches app views; only the terminal route renders the creation panel.
+function isPendingCreationSurfaceVisible(creationId: string): boolean {
+  const state = useAppStore.getState()
+  return state.activeView === 'terminal' && state.activePendingCreationId === creationId
+}
+
+async function preflightAgentTrust(
+  request: WorktreeCreationRequest,
+  path: string,
+  connectionId?: string | null
+): Promise<void> {
+  // Why: trust-gated agents (cursor-agent, copilot) consume the bracketed paste
+  // as menu input on first launch. Pre-write the trust artifact before any
+  // terminal spawns. Best-effort — the worktree already exists, so a failure
+  // here must not strand it.
+  if (!request.agent || !window.api.agentTrust?.markTrusted) {
+    return
+  }
+  const preflight = TUI_AGENT_CONFIG[request.agent].preflightTrust
+  if (!preflight) {
+    return
+  }
+  try {
+    await window.api.agentTrust.markTrusted({
+      preset: preflight,
+      workspacePath: path,
+      ...(connectionId ? { connectionId } : {})
+    })
+  } catch {
+    // Best-effort: continue with launch.
+  }
+}
+
+export async function executeWorktreeCreation(
+  creationId: string,
+  request: WorktreeCreationRequest
+): Promise<void> {
+  const preparedRequest = await prepareRequestForCreate(creationId, request)
+  if (!preparedRequest) {
+    return
+  }
+
+  let result: CreateWorktreeResult
+  try {
+    const provisionedRoot = getProvisionedRootCreateOptions(preparedRequest)
+    const backendStartup = provisionedRoot ? undefined : resolveBackendDraftStartup(preparedRequest)
+    result = await useAppStore
+      .getState()
+      .createWorktree(
+        preparedRequest.repoId,
+        preparedRequest.name,
+        preparedRequest.baseBranch,
+        preparedRequest.setupDecision,
+        preparedRequest.sparseCheckout,
+        preparedRequest.telemetrySource,
+        preparedRequest.displayName,
+        preparedRequest.linkedIssue,
+        preparedRequest.linkedPR,
+        preparedRequest.pushTarget,
+        preparedRequest.agent ?? undefined,
+        preparedRequest.linkedLinearIssue,
+        preparedRequest.branchNameOverride,
+        preparedRequest.workspaceStatus,
+        preparedRequest.linkedGitLabMR,
+        preparedRequest.linkedGitLabIssue,
+        backendStartup,
+        preparedRequest.pendingFirstAgentMessageRename,
+        creationId,
+        preparedRequest.linkedLinearIssueWorkspaceId,
+        preparedRequest.linkedLinearIssueOrganizationUrlKey,
+        preparedRequest.linkedBitbucketPR,
+        preparedRequest.linkedAzureDevOpsPR,
+        preparedRequest.linkedGiteaPR,
+        preparedRequest.compareBaseRef,
+        {
+          ...(preparedRequest.nameWasGenerated ? { nameWasGenerated: true } : {}),
+          ...(preparedRequest.linkedWorkItem !== undefined
+            ? { linkedWorkItem: preparedRequest.linkedWorkItem }
+            : {}),
+          ...(preparedRequest.linkedTaskSourceContext !== undefined
+            ? { linkedTaskSourceContext: preparedRequest.linkedTaskSourceContext }
+            : {}),
+          // Why: the remote host must own task-draft startup so its initial terminal is the agent, not an idle fallback shell.
+          ...(!backendStartup && preparedRequest.agent && preparedRequest.launchDraftPrompt
+            ? { startupDraft: preparedRequest.launchDraftPrompt }
+            : {}),
+          ...(provisionedRoot ? { provisionedRoot } : {}),
+          ...(preparedRequest.parentWorktreeId
+            ? { parentWorktreeId: preparedRequest.parentWorktreeId }
+            : {})
+        }
+      )
+  } catch (error) {
+    // Why: a missing entry means the user cancelled mid-flight — abandon
+    // silently rather than surfacing an error for work they already dismissed.
+    if (!useAppStore.getState().pendingWorktreeCreations[creationId]) {
+      return
+    }
+    if (preparedRequest.ephemeralVmRuntimeId) {
+      await cleanupEphemeralVmRuntimeForFailedCreate(preparedRequest)
+    }
+    const message = getWorkspaceCreateErrorToastMessage(formatWorkspaceCreateError(error))
+    // Why: an error must stay on the same creation surface that owns the faux
+    // tab strip, rather than falling back to stale previous-workspace tabs.
+    useAppStore.getState().updatePendingWorktreeCreation(creationId, {
+      status: 'error',
+      error: message,
+      ...(preparedRequest.ephemeralVmRecipe ? { request } : {})
+    })
+    // Why: only toast when the panel isn't already showing this error (the user
+    // navigated away), so a visible failure isn't announced twice.
+    if (!isPendingCreationSurfaceVisible(creationId)) {
+      toast.error(message)
+    }
+    return
+  }
+
+  const worktree = result.worktree
+  // Why: cancellation can race a successful backend adoption; clean up again after it settles so an adopted workspace cannot outlive its destroyed VM.
+  if (!useAppStore.getState().pendingWorktreeCreations[creationId]) {
+    if (preparedRequest.ephemeralVmRuntimeId) {
+      await cleanupEphemeralVmRuntimeForFailedCreate(preparedRequest)
+    }
+    return
+  }
+  await attachEphemeralVmRuntimeToWorkspace(preparedRequest, worktree.id)
+
+  const backendSpawned = result.startupTerminal?.spawned === true
+  if (preparedRequest.startupPlan && !backendSpawned && !preparedRequest.startupPlan.launchToken) {
+    // Why: delayed delivery must target the exact pane spawned from this queued
+    // startup, so both halves of the handoff share one renderer-session token.
+    preparedRequest.startupPlan.launchToken = createBrowserUuid()
+  }
+  const startupOpt = buildWorktreeCreationStartupOpt(preparedRequest, backendSpawned)
+
+  if (worktree.path) {
+    const repoConnectionId =
+      useAppStore.getState().repos.find((repo) => repo.id === worktree.repoId)?.connectionId ?? null
+    await preflightAgentTrust(preparedRequest, worktree.path, repoConnectionId)
+  }
+
+  // `createWorktree` already inserted the real worktree row. Leaving for an app
+  // view keeps the create in the background, while selecting another workspace
+  // means the user still expects this task-launch handoff when it becomes ready;
+  // the entry guard prevents a late trust preflight from reviving a cancelled create.
+  const completionState = useAppStore.getState()
+  const shouldActivateOnCompletion =
+    completionState.pendingWorktreeCreations[creationId] !== undefined &&
+    (isPendingCreationSurfaceVisible(creationId) ||
+      (completionState.activeView === 'terminal' &&
+        completionState.activePendingCreationId === null))
+
+  let activation: ActivateAndRevealResult | false = false
+  let primaryTabId: string | null
+  if (shouldActivateOnCompletion) {
+    activation = activateAndRevealWorktree(worktree.id, {
+      sidebarRevealBehavior: 'auto',
+      ...(result.setup ? { setup: result.setup } : {}),
+      ...(result.defaultTabs ? { defaultTabs: result.defaultTabs } : {}),
+      ...(startupOpt ? { startup: startupOpt } : {}),
+      ...(preparedRequest.issueCommand ? { issueCommand: preparedRequest.issueCommand } : {}),
+      ...(backendSpawned ? { backendStartupTerminalSpawned: true } : {})
+    })
+    primaryTabId = activation === false ? null : activation.primaryTabId
+  } else {
+    // The user moved on. Seed the worktree's terminal + setup in the background
+    // (setActiveTab only writes global focus for the active worktree, so this is
+    // safe) without yanking them back to it.
+    primaryTabId = ensureWorktreeHasInitialTerminal(
+      useAppStore.getState(),
+      worktree.id,
+      startupOpt,
+      result.setup,
+      preparedRequest.issueCommand,
+      result.defaultTabs,
+      {
+        activateCreatedTabs: false,
+        ...(backendSpawned ? { backendStartupTerminalSpawned: true } : {})
+      }
+    )
+  }
+
+  // Why: clearing synchronously right after activation lets React commit the
+  // panel→terminal swap in one frame — no two-row flicker, no empty-terminal flash.
+  useAppStore.getState().removePendingWorktreeCreation(creationId, { cleanupVm: false })
+  seedAgentTabStateAfterWorktreeCreate({
+    request: preparedRequest,
+    worktreeId: worktree.id,
+    primaryTabId,
+    startupTerminalTabId: result.startupTerminal?.tabId,
+    backendSpawned
+  })
+  if (preparedRequest.startupPlan && !backendSpawned) {
+    void ensureAgentStartupInTerminal({
+      worktreeId: worktree.id,
+      primaryTabId,
+      startup: preparedRequest.startupPlan
+    })
+  }
+  if (shouldActivateOnCompletion && !preparedRequest.suppressTerminalFocusOnCompletion) {
+    queueWorkspaceActivationTerminalFocus(worktree.id, activation)
+  }
+
+  // Why: awaiting the note IPC before the swap would add a visible round-trip to
+  // the panel→terminal transition; it's cosmetic, so it runs last.
+  if (preparedRequest.note) {
+    try {
+      await useAppStore.getState().updateWorktreeMeta(worktree.id, {
+        comment: preparedRequest.note
+      })
+    } catch {
+      console.error('Failed to update worktree meta after creation')
+    }
+  }
+}
diff --git a/src/renderer/src/lib/worktree-creation-flow.ts b/src/renderer/src/lib/worktree-creation-flow.ts
index d99a9792282..2fc17f6abf9 100644
--- a/src/renderer/src/lib/worktree-creation-flow.ts
+++ b/src/renderer/src/lib/worktree-creation-flow.ts
@@ -1,31 +1,12 @@
-import { toast } from 'sonner'
 import { useAppStore } from '@/store'
-import { TUI_AGENT_CONFIG } from '../../../shared/tui-agent-config'
-import { activateAndRevealWorktree, type ActivateAndRevealResult } from '@/lib/worktree-activation'
-import { ensureWorktreeHasInitialTerminal } from '@/lib/worktree-initial-terminal-seeding'
-import { ensureAgentStartupInTerminal } from '@/lib/new-workspace'
-import { queueWorkspaceActivationTerminalFocus } from '@/lib/workspace-activation-terminal-focus'
-import {
-  attachEphemeralVmRuntimeToWorkspace,
-  cleanupEphemeralVmRuntimeForFailedCreate,
-  prepareRequestForCreate
-} from '@/lib/ephemeral-vm-worktree-creation'
-import { getProvisionedRootCreateOptions } from '@/lib/provisioned-root-create-options'
-import {
-  formatWorkspaceCreateError,
-  getWorkspaceCreateErrorToastMessage
-} from '@/lib/workspace-create-error-format'
-import type { CreateWorktreeResult } from '../../../shared/worktree/create-types'
 import {
   findPendingLinkedWorkItemCreationId,
   type WorktreeCreationPhase,
   type WorktreeCreationRequest
 } from '@/lib/pending-worktree-creation'
 import { createBrowserUuid } from '@/lib/browser-uuid'
-import { seedAgentTabStateAfterWorktreeCreate } from '@/lib/worktree-creation-agent-seeds'
-import { resolveBackendDraftStartup } from '@/lib/worktree-draft-startup-view-mode'
+import { executeWorktreeCreation } from '@/lib/worktree-creation-flow-execute'
 import {
-  buildWorktreeCreationStartupOpt,
   getInitialWorktreeCreationPhase,
   getWorktreeCreationIndeterminate
 } from '@/lib/worktree-creation-flow-startup'
@@ -34,13 +15,6 @@ type ContinueBackgroundWorktreeCreationOptions = {
   revealCreationSurface?: boolean
 }
 
-// Why: activePendingCreationId can outlive the terminal route when the user
-// switches app views; only the terminal route renders the creation panel.
-function isPendingCreationSurfaceVisible(creationId: string): boolean {
-  const state = useAppStore.getState()
-  return state.activeView === 'terminal' && state.activePendingCreationId === creationId
-}
-
 function revealPendingCreation(
   creationId: string,
   request: WorktreeCreationRequest,
@@ -65,213 +39,6 @@ function revealPendingCreation(
   store.setSidebarOpen(true)
 }
 
-async function preflightAgentTrust(
-  request: WorktreeCreationRequest,
-  path: string,
-  connectionId?: string | null
-): Promise<void> {
-  // Why: trust-gated agents (cursor-agent, copilot) consume the bracketed paste
-  // as menu input on first launch. Pre-write the trust artifact before any
-  // terminal spawns. Best-effort — the worktree already exists, so a failure
-  // here must not strand it.
-  if (!request.agent || !window.api.agentTrust?.markTrusted) {
-    return
-  }
-  const preflight = TUI_AGENT_CONFIG[request.agent].preflightTrust
-  if (!preflight) {
-    return
-  }
-  try {
-    await window.api.agentTrust.markTrusted({
-      preset: preflight,
-      workspacePath: path,
-      ...(connectionId ? { connectionId } : {})
-    })
-  } catch {
-    // Best-effort: continue with launch.
-  }
-}
-
-async function executeWorktreeCreation(
-  creationId: string,
-  request: WorktreeCreationRequest
-): Promise<void> {
-  const preparedRequest = await prepareRequestForCreate(creationId, request)
-  if (!preparedRequest) {
-    return
-  }
-
-  let result: CreateWorktreeResult
-  try {
-    const provisionedRoot = getProvisionedRootCreateOptions(preparedRequest)
-    const backendStartup = provisionedRoot ? undefined : resolveBackendDraftStartup(preparedRequest)
-    result = await useAppStore
-      .getState()
-      .createWorktree(
-        preparedRequest.repoId,
-        preparedRequest.name,
-        preparedRequest.baseBranch,
-        preparedRequest.setupDecision,
-        preparedRequest.sparseCheckout,
-        preparedRequest.telemetrySource,
-        preparedRequest.displayName,
-        preparedRequest.linkedIssue,
-        preparedRequest.linkedPR,
-        preparedRequest.pushTarget,
-        preparedRequest.agent ?? undefined,
-        preparedRequest.linkedLinearIssue,
-        preparedRequest.branchNameOverride,
-        preparedRequest.workspaceStatus,
-        preparedRequest.linkedGitLabMR,
-        preparedRequest.linkedGitLabIssue,
-        backendStartup,
-        preparedRequest.pendingFirstAgentMessageRename,
-        creationId,
-        preparedRequest.linkedLinearIssueWorkspaceId,
-        preparedRequest.linkedLinearIssueOrganizationUrlKey,
-        preparedRequest.linkedBitbucketPR,
-        preparedRequest.linkedAzureDevOpsPR,
-        preparedRequest.linkedGiteaPR,
-        preparedRequest.compareBaseRef,
-        {
-          ...(preparedRequest.nameWasGenerated ? { nameWasGenerated: true } : {}),
-          ...(preparedRequest.linkedWorkItem !== undefined
-            ? { linkedWorkItem: preparedRequest.linkedWorkItem }
-            : {}),
-          ...(preparedRequest.linkedTaskSourceContext !== undefined
-            ? { linkedTaskSourceContext: preparedRequest.linkedTaskSourceContext }
-            : {}),
-          // Why: the remote host must own task-draft startup so its initial terminal is the agent, not an idle fallback shell.
-          ...(!backendStartup && preparedRequest.agent && preparedRequest.launchDraftPrompt
-            ? { startupDraft: preparedRequest.launchDraftPrompt }
-            : {}),
-          ...(provisionedRoot ? { provisionedRoot } : {})
-        }
-      )
-  } catch (error) {
-    // Why: a missing entry means the user cancelled mid-flight — abandon
-    // silently rather than surfacing an error for work they already dismissed.
-    if (!useAppStore.getState().pendingWorktreeCreations[creationId]) {
-      return
-    }
-    if (preparedRequest.ephemeralVmRuntimeId) {
-      await cleanupEphemeralVmRuntimeForFailedCreate(preparedRequest)
-    }
-    const message = getWorkspaceCreateErrorToastMessage(formatWorkspaceCreateError(error))
-    // Why: an error must stay on the same creation surface that owns the faux
-    // tab strip, rather than falling back to stale previous-workspace tabs.
-    useAppStore.getState().updatePendingWorktreeCreation(creationId, {
-      status: 'error',
-      error: message,
-      ...(preparedRequest.ephemeralVmRecipe ? { request } : {})
-    })
-    // Why: only toast when the panel isn't already showing this error (the user
-    // navigated away), so a visible failure isn't announced twice.
-    if (!isPendingCreationSurfaceVisible(creationId)) {
-      toast.error(message)
-    }
-    return
-  }
-
-  const worktree = result.worktree
-  // Why: cancellation can race a successful backend adoption; clean up again after it settles so an adopted workspace cannot outlive its destroyed VM.
-  if (!useAppStore.getState().pendingWorktreeCreations[creationId]) {
-    if (preparedRequest.ephemeralVmRuntimeId) {
-      await cleanupEphemeralVmRuntimeForFailedCreate(preparedRequest)
-    }
-    return
-  }
-  await attachEphemeralVmRuntimeToWorkspace(preparedRequest, worktree.id)
-
-  const backendSpawned = result.startupTerminal?.spawned === true
-  if (preparedRequest.startupPlan && !backendSpawned && !preparedRequest.startupPlan.launchToken) {
-    // Why: delayed delivery must target the exact pane spawned from this queued
-    // startup, so both halves of the handoff share one renderer-session token.
-    preparedRequest.startupPlan.launchToken = createBrowserUuid()
-  }
-  const startupOpt = buildWorktreeCreationStartupOpt(preparedRequest, backendSpawned)
-
-  if (worktree.path) {
-    const repoConnectionId =
-      useAppStore.getState().repos.find((repo) => repo.id === worktree.repoId)?.connectionId ?? null
-    await preflightAgentTrust(preparedRequest, worktree.path, repoConnectionId)
-  }
-
-  // `createWorktree` already inserted the real worktree row. Leaving for an app
-  // view keeps the create in the background, while selecting another workspace
-  // means the user still expects this task-launch handoff when it becomes ready;
-  // the entry guard prevents a late trust preflight from reviving a cancelled create.
-  const completionState = useAppStore.getState()
-  const shouldActivateOnCompletion =
-    completionState.pendingWorktreeCreations[creationId] !== undefined &&
-    (isPendingCreationSurfaceVisible(creationId) ||
-      (completionState.activeView === 'terminal' &&
-        completionState.activePendingCreationId === null))
-
-  let activation: ActivateAndRevealResult | false = false
-  let primaryTabId: string | null
-  if (shouldActivateOnCompletion) {
-    activation = activateAndRevealWorktree(worktree.id, {
-      sidebarRevealBehavior: 'auto',
-      ...(result.setup ? { setup: result.setup } : {}),
-      ...(result.defaultTabs ? { defaultTabs: result.defaultTabs } : {}),
-      ...(startupOpt ? { startup: startupOpt } : {}),
-      ...(preparedRequest.issueCommand ? { issueCommand: preparedRequest.issueCommand } : {}),
-      ...(backendSpawned ? { backendStartupTerminalSpawned: true } : {})
-    })
-    primaryTabId = activation === false ? null : activation.primaryTabId
-  } else {
-    // The user moved on. Seed the worktree's terminal + setup in the background
-    // (setActiveTab only writes global focus for the active worktree, so this is
-    // safe) without yanking them back to it.
-    primaryTabId = ensureWorktreeHasInitialTerminal(
-      useAppStore.getState(),
-      worktree.id,
-      startupOpt,
-      result.setup,
-      preparedRequest.issueCommand,
-      result.defaultTabs,
-      {
-        activateCreatedTabs: false,
-        ...(backendSpawned ? { backendStartupTerminalSpawned: true } : {})
-      }
-    )
-  }
-
-  // Why: clearing synchronously right after activation lets React commit the
-  // panel→terminal swap in one frame — no two-row flicker, no empty-terminal flash.
-  useAppStore.getState().removePendingWorktreeCreation(creationId, { cleanupVm: false })
-  seedAgentTabStateAfterWorktreeCreate({
-    request: preparedRequest,
-    worktreeId: worktree.id,
-    primaryTabId,
-    startupTerminalTabId: result.startupTerminal?.tabId,
-    backendSpawned
-  })
-  if (preparedRequest.startupPlan && !backendSpawned) {
-    void ensureAgentStartupInTerminal({
-      worktreeId: worktree.id,
-      primaryTabId,
-      startup: preparedRequest.startupPlan
-    })
-  }
-  if (shouldActivateOnCompletion && !preparedRequest.suppressTerminalFocusOnCompletion) {
-    queueWorkspaceActivationTerminalFocus(worktree.id, activation)
-  }
-
-  // Why: awaiting the note IPC before the swap would add a visible round-trip to
-  // the panel→terminal transition; it's cosmetic, so it runs last.
-  if (preparedRequest.note) {
-    try {
-      await useAppStore.getState().updateWorktreeMeta(worktree.id, {
-        comment: preparedRequest.note
-      })
-    } catch {
-      console.error('Failed to update worktree meta after creation')
-    }
-  }
-}
-
 /**
  * Kick off a worktree create in the background. The caller (the composer) has
  * already resolved every interactive decision into `request`, so this returns
diff --git a/src/renderer/src/runtime/runtime-compatibility-test-fixture.ts b/src/renderer/src/runtime/runtime-compatibility-test-fixture.ts
index ccb20944e58..6fc2cfcd027 100644
--- a/src/renderer/src/runtime/runtime-compatibility-test-fixture.ts
+++ b/src/renderer/src/runtime/runtime-compatibility-test-fixture.ts
@@ -8,6 +8,7 @@ import {
 
 export type RuntimeEnvironmentCallRequest = {
   method: string
+  params?: Record<string, unknown>
 }
 
 export function createCompatibleRuntimeStatusResponse(
diff --git a/src/renderer/src/store/slices/worktree-helpers.ts b/src/renderer/src/store/slices/worktree-helpers.ts
index 5d4fafd1e22..d34c4d26036 100644
--- a/src/renderer/src/store/slices/worktree-helpers.ts
+++ b/src/renderer/src/store/slices/worktree-helpers.ts
@@ -1,3 +1,4 @@
+import type { CreateWorktreeCallOptions } from './worktrees/create/worktree-create-payload'
 import type { WorkspaceKey } from '../../../../shared/folder-workspace-types'
 import type { TuiAgent } from '../../../../shared/tui-agent'
 import type { WorkspaceSource as WorkspaceCreateTelemetrySource } from '../../../../shared/workspace-source'
@@ -7,7 +8,6 @@ import type {
 } from '../../../../shared/worktree/base-ref-drift-types'
 import type {
   CreateSparseCheckoutRequest,
-  CreateWorktreeArgs,
   CreateWorktreeResult,
   ForceDeleteWorktreeBranchResult,
   SetupDecision
@@ -19,11 +19,9 @@ import type {
   DetectedWorktree,
   DetectedWorktreeListResult,
   GitPushTarget,
-  WorkspaceLinkedItem,
   WorkspaceStatus,
   Worktree
 } from '../../../../shared/worktree/types'
-import type { TaskSourceContext } from '../../../../shared/task-source-context'
 import type { WorktreeRemovalTarget } from '../../../../shared/worktree/removal'
 import type { TerminalGitHubPRLink } from '../../../../shared/terminal-github-pr-link-detector'
 import type { ExecutionHostId } from '../../../../shared/execution-host'
@@ -208,20 +206,7 @@ export type WorktreeSlice = {
     linkedAzureDevOpsPR?: number | null,
     linkedGiteaPR?: number | null,
     compareBaseRef?: string,
-    options?: {
-      automationProvenanceRequest?: CreateWorktreeArgs['automationProvenanceRequest']
-      linkedWorkItem?: WorkspaceLinkedItem | null
-      linkedTaskSourceContext?: TaskSourceContext | null
-      /** Lets the owning runtime launch and prefill a task agent without first creating an idle shell. */
-      startupDraft?: string
-      /** True only when `name` came from the creature-name generator; gates host-side retirement. */
-      nameWasGenerated?: boolean
-      provisionedRoot?: {
-        runtimeId: string
-        executionHostId: ExecutionHostId
-        expectedPath: string
-      }
-    }
+    options?: CreateWorktreeCallOptions
   ) => Promise<CreateWorktreeResult>
   /** Register an in-flight background creation and make it the active surface. */
   beginPendingWorktreeCreation: (entry: PendingWorktreeCreation) => void
diff --git a/src/renderer/src/store/slices/worktrees-create-parent-pick.test.ts b/src/renderer/src/store/slices/worktrees-create-parent-pick.test.ts
new file mode 100644
index 00000000000..0e16557a1cf
--- /dev/null
+++ b/src/renderer/src/store/slices/worktrees-create-parent-pick.test.ts
@@ -0,0 +1,388 @@
+import { beforeEach, describe, expect, it, vi } from 'vitest'
+import type { AppState } from '../types'
+import type { Worktree } from '../../../../shared/worktree/types'
+import { toast } from 'sonner'
+import type { RuntimeEnvironmentCallRequest } from '../../runtime/runtime-compatibility-test-fixture'
+import { worktreeWorkspaceKey, folderWorkspaceKey } from '../../../../shared/workspace-scope'
+import { makeLineage, makeWorktree } from './worktrees-slice-test-fixtures'
+import {
+  createTestStore,
+  mockApi,
+  resetRemoteRuntimeMocks,
+  resetWorktreeSliceModuleMemory,
+  runtimeEnvironmentCall
+} from './worktrees-slice-test-harness'
+
+vi.mock('sonner', () => ({
+  toast: {
+    warning: vi.fn(),
+    info: vi.fn(),
+    success: vi.fn(),
+    error: vi.fn(),
+    dismiss: vi.fn()
+  }
+}))
+
+vi.mock('@/components/worktree-base-fallback-notice', () => ({
+  requestWorktreeBaseFallbackNotice: vi.fn()
+}))
+
+beforeEach(resetWorktreeSliceModuleMemory)
+
+describe('createWorktree composer parent pick', () => {
+  beforeEach(() => {
+    vi.clearAllMocks()
+    resetRemoteRuntimeMocks()
+  })
+
+  function createParentPickStore(parent?: Worktree) {
+    const store = createTestStore()
+    store.setState({ worktreesByRepo: { repo1: parent ? [parent] : [] } } as Partial<AppState>)
+    return store
+  }
+
+  function createWithParentPick(
+    store: ReturnType<typeof createTestStore>,
+    parentWorktreeId: string
+  ) {
+    const createWorktree = store.getState().createWorktree
+    const args: Parameters<typeof createWorktree> = ['repo1', 'feature', 'origin/main']
+    args[25] = { parentWorktreeId }
+    return createWorktree(...args)
+  }
+
+  it('nests the new workspace under the picked parent worktree', async () => {
+    const parent = makeWorktree({
+      id: 'repo1::/path/parent',
+      repoId: 'repo1',
+      path: '/path/parent',
+      instanceId: 'parent-instance'
+    })
+    const store = createParentPickStore(parent)
+    store.setState({ activeWorkspaceKey: folderWorkspaceKey('folder-1') } as Partial<AppState>)
+    mockApi.worktrees.create.mockResolvedValue({
+      worktree: makeWorktree({ id: 'repo1::/path/child', repoId: 'repo1', path: '/path/child' })
+    })
+
+    await createWithParentPick(store, parent.id)
+
+    expect(mockApi.worktrees.create).toHaveBeenCalledWith(
+      expect.objectContaining({ parentWorkspace: worktreeWorkspaceKey(parent.id) })
+    )
+  })
+
+  it('drops a stale parent pick and falls back to the active folder workspace', async () => {
+    const store = createParentPickStore()
+    store.setState({ activeWorkspaceKey: folderWorkspaceKey('folder-1') } as Partial<AppState>)
+    mockApi.worktrees.create.mockResolvedValue({
+      worktree: makeWorktree({ id: 'repo1::/path/child', repoId: 'repo1', path: '/path/child' })
+    })
+
+    await createWithParentPick(store, 'repo1::/path/removed')
+
+    expect(mockApi.worktrees.create).toHaveBeenCalledWith(
+      expect.objectContaining({ parentWorkspace: folderWorkspaceKey('folder-1') })
+    )
+  })
+
+  it('warns when an archived parent pick is dropped before create', async () => {
+    const parent = makeWorktree({
+      id: 'repo1::/path/parent',
+      repoId: 'repo1',
+      path: '/path/parent',
+      displayName: 'parent-wt',
+      isArchived: true
+    })
+    const store = createParentPickStore(parent)
+    mockApi.worktrees.create.mockResolvedValue({
+      worktree: makeWorktree({ id: 'repo1::/path/child', repoId: 'repo1', path: '/path/child' })
+    })
+
+    await createWithParentPick(store, parent.id)
+
+    expect(toast.warning).toHaveBeenCalledWith(
+      'Created without nesting under "parent-wt"',
+      expect.objectContaining({ description: expect.any(String) })
+    )
+  })
+
+  it('warns when the backend rejects an accepted parent pick', async () => {
+    const parent = makeWorktree({
+      id: 'repo1::/path/parent',
+      repoId: 'repo1',
+      path: '/path/parent',
+      displayName: 'parent-wt',
+      instanceId: 'parent-instance'
+    })
+    const store = createParentPickStore(parent)
+    mockApi.worktrees.create.mockResolvedValue({
+      worktree: makeWorktree({ id: 'repo1::/path/child', repoId: 'repo1', path: '/path/child' }),
+      lineage: null
+    })
+
+    await createWithParentPick(store, parent.id)
+
+    expect(toast.warning).toHaveBeenCalledWith(
+      'Created without nesting under "parent-wt"',
+      expect.objectContaining({ description: expect.any(String) })
+    )
+  })
+
+  it('keeps an accepted parent pick quiet and seeds its lineage', async () => {
+    const parent = makeWorktree({
+      id: 'repo1::/path/parent',
+      repoId: 'repo1',
+      path: '/path/parent',
+      instanceId: 'parent-instance'
+    })
+    const created = makeWorktree({
+      id: 'repo1::/path/child',
+      repoId: 'repo1',
+      path: '/path/child',
+      instanceId: 'child-instance'
+    })
+    const lineage = makeLineage({
+      worktreeId: created.id,
+      worktreeInstanceId: 'child-instance',
+      parentWorktreeId: parent.id,
+      parentWorktreeInstanceId: 'parent-instance'
+    })
+    const store = createParentPickStore(parent)
+    mockApi.worktrees.create.mockResolvedValue({ worktree: created, lineage })
+
+    await createWithParentPick(store, parent.id)
+
+    expect(toast.warning).not.toHaveBeenCalled()
+    expect(store.getState().worktreeLineageById[created.id]).toEqual(lineage)
+  })
+
+  // Why: paired web clients route window.api.worktrees.create to their host, which still rejects.
+  it('retries without the parent when the create API reports the parent is gone', async () => {
+    const parent = makeWorktree({
+      id: 'repo1::/path/parent',
+      repoId: 'repo1',
+      path: '/path/parent',
+      displayName: 'parent-wt',
+      instanceId: 'parent-instance'
+    })
+    const store = createParentPickStore(parent)
+    mockApi.worktrees.create
+      .mockRejectedValueOnce(
+        Object.assign(new Error('Parent selector was not found.'), {
+          code: 'LINEAGE_PARENT_NOT_FOUND'
+        })
+      )
+      .mockResolvedValue({
+        worktree: makeWorktree({ id: 'repo1::/path/child', repoId: 'repo1', path: '/path/child' })
+      })
+
+    await createWithParentPick(store, parent.id)
+
+    expect(mockApi.worktrees.create).toHaveBeenCalledTimes(2)
+    expect(mockApi.worktrees.create.mock.calls[1][0]).not.toHaveProperty('parentWorkspace')
+    expect(toast.warning).toHaveBeenCalledTimes(1)
+  })
+
+  it('warns once when a dropped pick is followed by branch-conflict retries', async () => {
+    const store = createParentPickStore()
+    const created = makeWorktree({
+      id: 'repo1::/path/child',
+      repoId: 'repo1',
+      path: '/path/child'
+    })
+    mockApi.worktrees.create
+      .mockRejectedValueOnce(new Error('Branch "feature" already exists locally.'))
+      .mockResolvedValue({ worktree: created })
+
+    await createWithParentPick(store, 'repo1::/path/removed')
+
+    expect(mockApi.worktrees.create).toHaveBeenCalledTimes(2)
+    expect(toast.warning).toHaveBeenCalledTimes(1)
+  })
+})
+
+describe('createWorktree parent pick on a remote runtime', () => {
+  const REMOTE_REPO = 'repo-remote'
+  const PARENT_ID = `${REMOTE_REPO}::/remote/parent`
+
+  beforeEach(() => {
+    vi.clearAllMocks()
+    resetRemoteRuntimeMocks()
+  })
+
+  function createRemoteStore() {
+    const store = createTestStore()
+    store.setState({
+      repos: [
+        {
+          id: REMOTE_REPO,
+          path: '/home/dev/repo',
+          displayName: 'repo',
+          badgeColor: '#000',
+          addedAt: 0,
+          executionHostId: 'runtime:env-1'
+        }
+      ],
+      worktreesByRepo: {
+        [REMOTE_REPO]: [
+          makeWorktree({
+            id: PARENT_ID,
+            repoId: REMOTE_REPO,
+            path: '/remote/parent',
+            displayName: 'parent-wt',
+            instanceId: 'parent-instance'
+          })
+        ]
+      }
+    } as Partial<AppState>)
+    return store
+  }
+
+  function createOnRemote(store: ReturnType<typeof createTestStore>) {
+    const createWorktree = store.getState().createWorktree
+    const args: Parameters<typeof createWorktree> = [REMOTE_REPO, 'feature', 'origin/main']
+    args[25] = { parentWorktreeId: PARENT_ID }
+    return createWorktree(...args)
+  }
+
+  function createCalls() {
+    return runtimeEnvironmentCall.mock.calls
+      .map(([request]: [RuntimeEnvironmentCallRequest]) => request)
+      .filter((request) => request.method === 'worktree.create')
+  }
+
+  function mockRuntimeCreate(firstCreate: (id: string) => unknown) {
+    let createCount = 0
+    runtimeEnvironmentCall.mockImplementation(({ method }: RuntimeEnvironmentCallRequest) => {
+      if (method !== 'worktree.create') {
+        return Promise.resolve({ id: method, ok: true, result: null })
+      }
+      createCount += 1
+      return createCount === 1
+        ? Promise.resolve(firstCreate('rpc-create'))
+        : Promise.resolve({
+            id: 'rpc-create',
+            ok: true,
+            result: {
+              worktree: makeWorktree({
+                id: `${REMOTE_REPO}::/remote/child`,
+                repoId: REMOTE_REPO,
+                path: '/remote/child'
+              })
+            }
+          })
+    })
+  }
+
+  it('marks an app-selected parent as manual so the host does not record a CLI flag', async () => {
+    mockRuntimeCreate((id) => ({
+      id,
+      ok: true,
+      result: {
+        worktree: makeWorktree({
+          id: `${REMOTE_REPO}::/remote/child`,
+          repoId: REMOTE_REPO,
+          path: '/remote/child'
+        }),
+        lineage: makeLineage({
+          worktreeId: `${REMOTE_REPO}::/remote/child`,
+          parentWorktreeId: PARENT_ID
+        })
+      }
+    }))
+
+    await createOnRemote(createRemoteStore())
+
+    expect(createCalls()[0]?.params).toMatchObject({
+      parentWorkspace: worktreeWorkspaceKey(PARENT_ID),
+      parentWorkspaceOrigin: 'manual'
+    })
+    expect(toast.warning).not.toHaveBeenCalled()
+  })
+
+  it('retries without the parent and warns when the host no longer has it', async () => {
+    mockRuntimeCreate((id) => ({
+      id,
+      ok: false,
+      error: { code: 'LINEAGE_PARENT_NOT_FOUND', message: 'Parent selector was not found.' }
+    }))
+
+    await createOnRemote(createRemoteStore())
+
+    const calls = createCalls()
+    expect(calls).toHaveLength(2)
+    expect(calls[1]?.params).not.toHaveProperty('parentWorkspace')
+    expect(toast.warning).toHaveBeenCalledWith(
+      'Created without nesting under "parent-wt"',
+      expect.objectContaining({ description: expect.any(String) })
+    )
+  })
+
+  it('retries when a transport re-wraps the parent-missing code into a plain error', async () => {
+    let createCount = 0
+    runtimeEnvironmentCall.mockImplementation(({ method }: RuntimeEnvironmentCallRequest) => {
+      if (method !== 'worktree.create') {
+        return Promise.resolve({ id: method, ok: true, result: null })
+      }
+      createCount += 1
+      // Why: the relay envelope re-throws as a plain Error, so only the trailing code survives.
+      return createCount === 1
+        ? Promise.reject(new Error('Error invoking remote method: LINEAGE_PARENT_NOT_FOUND'))
+        : Promise.resolve({
+            id: 'rpc-create',
+            ok: true,
+            result: {
+              worktree: makeWorktree({
+                id: `${REMOTE_REPO}::/remote/child`,
+                repoId: REMOTE_REPO,
+                path: '/remote/child'
+              })
+            }
+          })
+    })
+
+    await createOnRemote(createRemoteStore())
+
+    expect(createCalls()).toHaveLength(2)
+    expect(toast.warning).toHaveBeenCalledTimes(1)
+  })
+
+  // Why: the folder parent comes from the active scope, not a pick, so nothing else would surface it.
+  it('warns when the retry drops an active folder-workspace parent', async () => {
+    const store = createRemoteStore()
+    store.setState({
+      activeWorkspaceKey: folderWorkspaceKey('folder-1'),
+      folderWorkspaces: [{ id: 'folder-1', name: 'Design docs' }]
+    } as unknown as Partial<AppState>)
+    mockRuntimeCreate((id) => ({
+      id,
+      ok: false,
+      error: { code: 'LINEAGE_PARENT_NOT_FOUND', message: 'Parent selector was not found.' }
+    }))
+    const createWorktree = store.getState().createWorktree
+
+    await createWorktree(REMOTE_REPO, 'feature', 'origin/main')
+
+    const calls = createCalls()
+    expect(calls).toHaveLength(2)
+    expect(calls[0]?.params).toMatchObject({ parentWorkspace: folderWorkspaceKey('folder-1') })
+    expect(calls[1]?.params).not.toHaveProperty('parentWorkspace')
+    expect(toast.warning).toHaveBeenCalledWith(
+      'Created without nesting under "Design docs"',
+      expect.objectContaining({ description: expect.any(String) })
+    )
+  })
+
+  it('never double-creates when the host fails for an unrelated reason', async () => {
+    mockRuntimeCreate((id) => ({
+      id,
+      ok: false,
+      error: { code: 'internal_error', message: 'disk on fire' }
+    }))
+
+    await expect(createOnRemote(createRemoteStore())).rejects.toThrow('disk on fire')
+
+    expect(createCalls()).toHaveLength(1)
+    expect(toast.warning).not.toHaveBeenCalled()
+  })
+})
diff --git a/src/renderer/src/store/slices/worktrees-fetch-remote-lineage.test.ts b/src/renderer/src/store/slices/worktrees-fetch-remote-lineage.test.ts
index a7e4dff8a27..edd73074f57 100644
--- a/src/renderer/src/store/slices/worktrees-fetch-remote-lineage.test.ts
+++ b/src/renderer/src/store/slices/worktrees-fetch-remote-lineage.test.ts
@@ -266,6 +266,223 @@ describe('fetchWorktrees', () => {
     })
   })
 
+  it('keeps a lineage row written while the host lineage request was in flight', async () => {
+    const store = createTestStore()
+    const worktree = makeWorktree({
+      id: 'repo1::/remote/wt1',
+      repoId: 'repo1',
+      path: '/remote/wt1',
+      branch: 'refs/heads/remote',
+      hostId: 'runtime:env-1'
+    })
+    store.setState({
+      settings: { activeRuntimeEnvironmentId: 'env-1' } as never,
+      worktreesByRepo: { repo1: [worktree] },
+      worktreeLineageById: {},
+      workspaceLineageByChildKey: {}
+    } as Partial<AppState>)
+
+    let releaseLineage: (() => void) | undefined
+    const lineageReplied = new Promise<void>((resolve) => {
+      releaseLineage = resolve
+    })
+    runtimeEnvironmentCall.mockImplementation(async ({ method }: RuntimeEnvironmentCallRequest) => {
+      if (method === 'worktree.lineageList') {
+        await lineageReplied
+        return {
+          id: 'rpc-1',
+          ok: true,
+          result: { lineage: {}, workspaceLineage: {} },
+          _meta: { runtimeId: 'runtime-remote' }
+        }
+      }
+      return {
+        id: 'rpc-2',
+        ok: true,
+        result: makeDetectedResult('repo1', [worktree]),
+        _meta: { runtimeId: 'runtime-remote' }
+      }
+    })
+
+    const pending = store.getState().fetchWorktreeLineage({ executionHostId: 'runtime:env-1' })
+    const created = makeLineage({ worktreeId: worktree.id })
+    const createdWorkspace = makeWorkspaceLineage({
+      childWorkspaceKey: worktreeWorkspaceKey(worktree.id)
+    })
+    store.setState({
+      worktreeLineageById: { [created.worktreeId]: created },
+      workspaceLineageByChildKey: { [createdWorkspace.childWorkspaceKey]: createdWorkspace }
+    } as Partial<AppState>)
+
+    releaseLineage?.()
+    await pending
+
+    expect(store.getState().worktreeLineageById).toEqual({ [created.worktreeId]: created })
+    expect(store.getState().workspaceLineageByChildKey).toEqual({
+      [createdWorkspace.childWorkspaceKey]: createdWorkspace
+    })
+  })
+
+  it('keeps a parent reassignment written while the host lineage request was in flight', async () => {
+    const store = createTestStore()
+    const worktree = makeWorktree({
+      id: 'repo1::/remote/wt1',
+      repoId: 'repo1',
+      path: '/remote/wt1',
+      branch: 'refs/heads/remote',
+      hostId: 'runtime:env-1'
+    })
+    const childKey = worktreeWorkspaceKey(worktree.id)
+    const before = makeLineage({
+      worktreeId: worktree.id,
+      parentWorktreeId: 'repo1::/remote/old-parent'
+    })
+    const beforeWorkspace = makeWorkspaceLineage({
+      childWorkspaceKey: childKey,
+      parentWorkspaceKey: worktreeWorkspaceKey('repo1::/remote/old-parent')
+    })
+    store.setState({
+      settings: { activeRuntimeEnvironmentId: 'env-1' } as never,
+      worktreesByRepo: { repo1: [worktree] },
+      worktreeLineageById: { [before.worktreeId]: before },
+      workspaceLineageByChildKey: { [childKey]: beforeWorkspace }
+    } as Partial<AppState>)
+
+    let releaseLineage: (() => void) | undefined
+    const lineageReplied = new Promise<void>((resolve) => {
+      releaseLineage = resolve
+    })
+    runtimeEnvironmentCall.mockImplementation(async ({ method }: RuntimeEnvironmentCallRequest) => {
+      if (method === 'worktree.lineageList') {
+        await lineageReplied
+        return {
+          id: 'rpc-1',
+          ok: true,
+          result: {
+            lineage: { [before.worktreeId]: before },
+            workspaceLineage: { [childKey]: beforeWorkspace }
+          },
+          _meta: { runtimeId: 'runtime-remote' }
+        }
+      }
+      return {
+        id: 'rpc-2',
+        ok: true,
+        result: makeDetectedResult('repo1', [worktree]),
+        _meta: { runtimeId: 'runtime-remote' }
+      }
+    })
+
+    const pending = store.getState().fetchWorktreeLineage({ executionHostId: 'runtime:env-1' })
+    const reassigned = makeLineage({
+      worktreeId: worktree.id,
+      parentWorktreeId: 'repo1::/remote/new-parent'
+    })
+    const reassignedWorkspace = makeWorkspaceLineage({
+      childWorkspaceKey: childKey,
+      parentWorkspaceKey: worktreeWorkspaceKey('repo1::/remote/new-parent')
+    })
+    store.setState({
+      worktreeLineageById: { [reassigned.worktreeId]: reassigned },
+      workspaceLineageByChildKey: { [childKey]: reassignedWorkspace }
+    } as Partial<AppState>)
+
+    releaseLineage?.()
+    await pending
+
+    expect(store.getState().worktreeLineageById).toEqual({ [reassigned.worktreeId]: reassigned })
+    expect(store.getState().workspaceLineageByChildKey).toEqual({ [childKey]: reassignedWorkspace })
+  })
+
+  it('keeps a lineage row deleted while the host lineage request was in flight', async () => {
+    const store = createTestStore()
+    const worktree = makeWorktree({
+      id: 'repo1::/remote/wt1',
+      repoId: 'repo1',
+      path: '/remote/wt1',
+      branch: 'refs/heads/remote',
+      hostId: 'runtime:env-1'
+    })
+    const childKey = worktreeWorkspaceKey(worktree.id)
+    const before = makeLineage({ worktreeId: worktree.id })
+    const beforeWorkspace = makeWorkspaceLineage({ childWorkspaceKey: childKey })
+    store.setState({
+      settings: { activeRuntimeEnvironmentId: 'env-1' } as never,
+      worktreesByRepo: { repo1: [worktree] },
+      worktreeLineageById: { [before.worktreeId]: before },
+      workspaceLineageByChildKey: { [childKey]: beforeWorkspace }
+    } as Partial<AppState>)
+
+    let releaseLineage: (() => void) | undefined
+    const lineageReplied = new Promise<void>((resolve) => {
+      releaseLineage = resolve
+    })
+    runtimeEnvironmentCall.mockImplementation(async ({ method }: RuntimeEnvironmentCallRequest) => {
+      if (method === 'worktree.lineageList') {
+        await lineageReplied
+        return {
+          id: 'rpc-1',
+          ok: true,
+          result: {
+            lineage: { [before.worktreeId]: before },
+            workspaceLineage: { [childKey]: beforeWorkspace }
+          },
+          _meta: { runtimeId: 'runtime-remote' }
+        }
+      }
+      return {
+        id: 'rpc-2',
+        ok: true,
+        result: makeDetectedResult('repo1', [worktree]),
+        _meta: { runtimeId: 'runtime-remote' }
+      }
+    })
+
+    const pending = store.getState().fetchWorktreeLineage({ executionHostId: 'runtime:env-1' })
+    store.setState({
+      worktreeLineageById: {},
+      workspaceLineageByChildKey: {}
+    } as Partial<AppState>)
+
+    releaseLineage?.()
+    await pending
+
+    expect(store.getState().worktreeLineageById).toEqual({})
+    expect(store.getState().workspaceLineageByChildKey).toEqual({})
+  })
+
+  it('drops a host lineage row the refresh reply no longer reports', async () => {
+    const store = createTestStore()
+    const worktree = makeWorktree({
+      id: 'repo1::/remote/wt1',
+      repoId: 'repo1',
+      path: '/remote/wt1',
+      branch: 'refs/heads/remote',
+      hostId: 'runtime:env-1'
+    })
+    const stale = makeLineage({ worktreeId: worktree.id })
+    store.setState({
+      settings: { activeRuntimeEnvironmentId: 'env-1' } as never,
+      worktreesByRepo: { repo1: [worktree] },
+      worktreeLineageById: { [stale.worktreeId]: stale }
+    } as Partial<AppState>)
+    runtimeEnvironmentCall.mockImplementation(({ method }: RuntimeEnvironmentCallRequest) =>
+      Promise.resolve({
+        id: 'rpc-1',
+        ok: true,
+        result:
+          method === 'worktree.lineageList'
+            ? { lineage: {}, workspaceLineage: {} }
+            : makeDetectedResult('repo1', [worktree]),
+        _meta: { runtimeId: 'runtime-remote' }
+      })
+    )
+
+    await store.getState().fetchWorktreeLineage({ executionHostId: 'runtime:env-1' })
+
+    expect(store.getState().worktreeLineageById).toEqual({})
+  })
+
   it('keeps a successful remote worktree refresh when lineage refresh fails', async () => {
     const store = createTestStore()
     const refreshed = makeWorktree({
diff --git a/src/renderer/src/store/slices/worktrees/create/create-worktree.ts b/src/renderer/src/store/slices/worktrees/create/create-worktree.ts
index a21207805a9..b4f8bc75bc8 100644
--- a/src/renderer/src/store/slices/worktrees/create/create-worktree.ts
+++ b/src/renderer/src/store/slices/worktrees/create/create-worktree.ts
@@ -1,12 +1,12 @@
 import type { WorktreeSlice } from '../../worktree-helpers'
 import type { WorktreeSliceGet, WorktreeSliceSet } from '../listing/worktree-slice-types'
+import type { CreateWorktreeResult } from '../../../../../../shared/worktree/create-types'
 import {
   CLIENT_WORKTREE_CREATE_MAX_ATTEMPTS,
   getClientWorktreeCreateCandidate,
   getGeneratedWorktreeCreateRetryCandidate,
   isRetryableWorktreeCreateConflict
 } from '../../../../../../shared/new-workspace/worktree-create-retry-policy'
-import { parseWorkspaceKey, folderWorkspaceKey } from '../../../../../../shared/workspace-scope'
 import {
   assertRuntimeEnvironmentCapability,
   callRuntimeRpc,
@@ -16,12 +16,82 @@ import { WORKTREE_LINKED_WORK_ITEM_CONTEXT_RUNTIME_CAPABILITY } from '../../../.
 import { showLocalBaseRefUpdateSuggestionToast } from '@/components/sidebar/local-base-ref-suggestion-toast'
 import { requestWorktreeBaseFallbackNotice } from '@/components/worktree-base-fallback-notice'
 import { showLocalBaseRefRefreshToast } from './local-base-ref-refresh-toast'
-import {
-  getProjectHostSetupForRepoHost,
-  repoHostId,
-  withRepoHostOwnership
-} from '../listing/worktree-host-ownership'
 import { settingsForRepoOwner } from '../listing/worktree-owner-settings'
+import { applyCreatedWorktree } from './created-worktree-state-merge'
+import { isRuntimeLineageParentMissingError } from '../listing/runtime-worktree-rpc-errors'
+import {
+  buildLocalWorktreeCreateArgs,
+  buildRuntimeWorktreeCreateParams,
+  type WorktreeCreateAttempt,
+  type WorktreeCreateRequest
+} from './worktree-create-payload'
+import {
+  notifyWorktreeParentDropped,
+  resolveWorktreeCreateParent,
+  type WorktreeCreateParentPick
+} from './worktree-create-parent-pick'
+
+type RuntimeTarget = ReturnType<typeof getActiveRuntimeTarget>
+
+type CreateAttemptOutcome = {
+  result: CreateWorktreeResult
+  /** The host had no such parent, so this attempt was retried unattached. */
+  droppedParent: boolean
+}
+
+async function runCreateAttempt(
+  request: WorktreeCreateRequest,
+  attempt: WorktreeCreateAttempt,
+  target: RuntimeTarget
+): Promise<CreateAttemptOutcome> {
+  const provisionedRoot = request.options?.provisionedRoot
+  const create = async (
+    parentWorkspace: WorktreeCreateAttempt['parentWorkspace']
+  ): Promise<CreateWorktreeResult> =>
+    provisionedRoot
+      ? await window.api.worktrees.adoptProvisionedRoot({
+          ...buildLocalWorktreeCreateArgs(request, { ...attempt, parentWorkspace }),
+          ...provisionedRoot
+        })
+      : target.kind === 'local'
+        ? // Why local can still reject on the parent: paired web clients route this API to their host.
+          await window.api.worktrees.create(
+            buildLocalWorktreeCreateArgs(request, { ...attempt, parentWorkspace })
+          )
+        : await callRuntimeRpc<CreateWorktreeResult>(
+            target,
+            'worktree.create',
+            buildRuntimeWorktreeCreateParams(request, { ...attempt, parentWorkspace }),
+            { timeoutMs: 10 * 60_000 }
+          )
+  try {
+    return { result: await create(attempt.parentWorkspace), droppedParent: false }
+  } catch (error) {
+    if (!attempt.parentWorkspace || !isRuntimeLineageParentMissingError(error)) {
+      throw error
+    }
+    return { result: await create(undefined), droppedParent: true }
+  }
+}
+
+/** True when the create landed without the nesting the caller asked for. */
+function lostRequestedParent(
+  outcome: CreateAttemptOutcome,
+  parent: WorktreeCreateParentPick,
+  target: RuntimeTarget
+): boolean {
+  if (outcome.droppedParent) {
+    return true
+  }
+  if (parent.pickedParentWorktreeId) {
+    return !outcome.result.lineage
+  }
+  // Why local-only: older hosts predate the top-level workspace lineage field, so its absence
+  // over RPC would warn about a nesting that actually landed.
+  return (
+    target.kind === 'local' && Boolean(parent.parentWorkspace) && !outcome.result.workspaceLineage
+  )
+}
 
 export function createCreateWorktree(
   set: WorktreeSliceSet,
@@ -55,188 +125,87 @@ export function createCreateWorktree(
     compareBaseRef,
     options
   ) => {
-    const automationProvenanceRequest = options?.automationProvenanceRequest
-    const linkedWorkItem = options?.linkedWorkItem
-    const linkedTaskSourceContext = options?.linkedTaskSourceContext
-    const startupDraft = options?.startupDraft
-    const provisionedRoot = options?.provisionedRoot
+    const request: WorktreeCreateRequest = {
+      repoId,
+      name,
+      baseBranch,
+      setupDecision,
+      sparseCheckout,
+      telemetrySource,
+      displayName,
+      linkedIssue,
+      linkedPR,
+      pushTarget,
+      createdWithAgent,
+      linkedLinearIssue,
+      branchNameOverride,
+      workspaceStatus,
+      linkedGitLabMR,
+      linkedGitLabIssue,
+      startup,
+      pendingFirstAgentMessageRename,
+      creationId,
+      linkedLinearIssueWorkspaceId,
+      linkedLinearIssueOrganizationUrlKey,
+      linkedBitbucketPR,
+      linkedAzureDevOpsPR,
+      linkedGiteaPR,
+      compareBaseRef,
+      options
+    }
     try {
+      // Why outside the retry loop: a branch-name conflict retry must not re-warn about the same dropped pick.
+      const parent = resolveWorktreeCreateParent(get(), repoId, options?.parentWorktreeId)
+      let warnedParentDropped = false
+      const warnParentDroppedOnce = (): void => {
+        if (warnedParentDropped) {
+          return
+        }
+        warnedParentDropped = true
+        notifyWorktreeParentDropped(get(), parent)
+      }
+      if (parent.staleBeforeCreate) {
+        warnParentDroppedOnce()
+      }
+      // Why: manual sort is user-authored order; stamp new workspaces at the top rather than relying on sortOrder fallback.
+      const manualOrder = get().sortBy === 'manual' ? Date.now() : undefined
+      const target = getActiveRuntimeTarget(settingsForRepoOwner(get(), repoId))
+      if (
+        target.kind === 'environment' &&
+        (options?.linkedWorkItem?.provider === 'jira' ||
+          options?.linkedTaskSourceContext?.provider === 'jira')
+      ) {
+        await assertRuntimeEnvironmentCapability(
+          target.environmentId,
+          WORKTREE_LINKED_WORK_ITEM_CONTEXT_RUNTIME_CAPABILITY,
+          'Update the remote runtime to link Jira'
+        )
+      }
+      if (options?.provisionedRoot && target.kind !== 'local') {
+        throw new Error('Provisioned-root recipes currently require a direct SSH connection.')
+      }
       for (let attempt = 0; attempt < CLIENT_WORKTREE_CREATE_MAX_ATTEMPTS; attempt += 1) {
-        const candidateName = options?.nameWasGenerated
-          ? getGeneratedWorktreeCreateRetryCandidate(name, attempt)
-          : getClientWorktreeCreateCandidate(name, attempt)
-        // Why: older runtimes reject exact PR branch overrides on collision, so retry both branch and worktree names.
-        const candidateBranchNameOverride = branchNameOverride
-          ? getClientWorktreeCreateCandidate(branchNameOverride, attempt)
-          : undefined
         try {
-          // Why: manual sort is user-authored order; stamp new workspaces at the top rather than relying on sortOrder fallback.
-          const manualOrder = get().sortBy === 'manual' ? Date.now() : undefined
-          const activeScope = parseWorkspaceKey(get().activeWorkspaceKey ?? '')
-          const parentWorkspace =
-            activeScope?.type === 'folder'
-              ? folderWorkspaceKey(activeScope.folderWorkspaceId)
-              : undefined
-          const createArgs = {
-            repoId,
-            name: candidateName,
-            ...(options?.nameWasGenerated ? { nameWasGenerated: true } : {}),
-            baseBranch,
-            ...(compareBaseRef ? { compareBaseRef } : {}),
-            ...(candidateBranchNameOverride
-              ? { branchNameOverride: candidateBranchNameOverride }
-              : {}),
-            setupDecision,
-            sparseCheckout,
-            ...(displayName ? { displayName } : {}),
-            ...(telemetrySource ? { telemetrySource } : {}),
-            ...(linkedIssue !== undefined ? { linkedIssue } : {}),
-            ...(linkedPR !== undefined ? { linkedPR } : {}),
-            ...(pushTarget ? { pushTarget } : {}),
-            ...(createdWithAgent ? { createdWithAgent } : {}),
-            ...(pendingFirstAgentMessageRename === true && createdWithAgent
-              ? { pendingFirstAgentMessageRename: true }
-              : {}),
-            ...(linkedLinearIssue !== undefined ? { linkedLinearIssue } : {}),
-            ...(linkedLinearIssueWorkspaceId !== undefined ? { linkedLinearIssueWorkspaceId } : {}),
-            ...(linkedLinearIssueOrganizationUrlKey !== undefined
-              ? { linkedLinearIssueOrganizationUrlKey }
-              : {}),
-            ...(manualOrder !== undefined ? { manualOrder } : {}),
-            ...(parentWorkspace ? { parentWorkspace } : {}),
-            ...(workspaceStatus !== undefined ? { workspaceStatus } : {}),
-            ...(linkedGitLabMR !== undefined ? { linkedGitLabMR } : {}),
-            ...(linkedGitLabIssue !== undefined ? { linkedGitLabIssue } : {}),
-            ...(linkedBitbucketPR !== undefined ? { linkedBitbucketPR } : {}),
-            ...(linkedAzureDevOpsPR !== undefined ? { linkedAzureDevOpsPR } : {}),
-            ...(linkedGiteaPR !== undefined ? { linkedGiteaPR } : {}),
-            ...(linkedWorkItem !== undefined ? { linkedWorkItem } : {}),
-            ...(linkedTaskSourceContext !== undefined ? { linkedTaskSourceContext } : {}),
-            ...(startup ? { startup } : {}),
-            ...(creationId ? { creationId } : {}),
-            ...(automationProvenanceRequest ? { automationProvenanceRequest } : {})
+          const outcome = await runCreateAttempt(
+            request,
+            {
+              name: options?.nameWasGenerated
+                ? getGeneratedWorktreeCreateRetryCandidate(name, attempt)
+                : getClientWorktreeCreateCandidate(name, attempt),
+              // Why: older runtimes reject exact PR branch overrides on collision, so retry both branch and worktree names.
+              branchNameOverride: branchNameOverride
+                ? getClientWorktreeCreateCandidate(branchNameOverride, attempt)
+                : undefined,
+              parentWorkspace: parent.parentWorkspace,
+              manualOrder
+            },
+            target
+          )
+          if (lostRequestedParent(outcome, parent, target)) {
+            warnParentDroppedOnce()
           }
-          const target = getActiveRuntimeTarget(settingsForRepoOwner(get(), repoId))
-          if (
-            target.kind === 'environment' &&
-            (linkedWorkItem?.provider === 'jira' || linkedTaskSourceContext?.provider === 'jira')
-          ) {
-            await assertRuntimeEnvironmentCapability(
-              target.environmentId,
-              WORKTREE_LINKED_WORK_ITEM_CONTEXT_RUNTIME_CAPABILITY,
-              'Update the remote runtime to link Jira'
-            )
-          }
-          if (provisionedRoot && target.kind !== 'local') {
-            throw new Error('Provisioned-root recipes currently require a direct SSH connection.')
-          }
-          const result = provisionedRoot
-            ? await window.api.worktrees.adoptProvisionedRoot({
-                ...createArgs,
-                ...provisionedRoot
-              })
-            : target.kind === 'local'
-              ? await window.api.worktrees.create(createArgs)
-              : await callRuntimeRpc<Awaited<ReturnType<typeof window.api.worktrees.create>>>(
-                  target,
-                  'worktree.create',
-                  {
-                    repo: repoId,
-                    name: candidateName,
-                    ...(options?.nameWasGenerated ? { nameWasGenerated: true } : {}),
-                    baseBranch,
-                    ...(compareBaseRef ? { compareBaseRef } : {}),
-                    ...(candidateBranchNameOverride
-                      ? { branchNameOverride: candidateBranchNameOverride }
-                      : {}),
-                    setupDecision,
-                    sparseCheckout,
-                    ...(displayName ? { displayName } : {}),
-                    ...(telemetrySource ? { telemetrySource } : {}),
-                    ...(linkedIssue !== undefined ? { linkedIssue } : {}),
-                    ...(linkedPR !== undefined ? { linkedPR } : {}),
-                    ...(pushTarget ? { pushTarget } : {}),
-                    ...(createdWithAgent ? { createdWithAgent } : {}),
-                    ...(pendingFirstAgentMessageRename === true && createdWithAgent
-                      ? { pendingFirstAgentMessageRename: true }
-                      : {}),
-                    ...(linkedLinearIssue !== undefined ? { linkedLinearIssue } : {}),
-                    ...(linkedLinearIssueWorkspaceId !== undefined
-                      ? { linkedLinearIssueWorkspaceId }
-                      : {}),
-                    ...(linkedLinearIssueOrganizationUrlKey !== undefined
-                      ? { linkedLinearIssueOrganizationUrlKey }
-                      : {}),
-                    ...(manualOrder !== undefined ? { manualOrder } : {}),
-                    ...(parentWorkspace ? { parentWorkspace } : {}),
-                    ...(workspaceStatus !== undefined ? { workspaceStatus } : {}),
-                    ...(linkedGitLabMR !== undefined ? { linkedGitLabMR } : {}),
-                    ...(linkedGitLabIssue !== undefined ? { linkedGitLabIssue } : {}),
-                    ...(linkedBitbucketPR !== undefined ? { linkedBitbucketPR } : {}),
-                    ...(linkedAzureDevOpsPR !== undefined ? { linkedAzureDevOpsPR } : {}),
-                    ...(linkedGiteaPR !== undefined ? { linkedGiteaPR } : {}),
-                    ...(linkedWorkItem !== undefined ? { linkedWorkItem } : {}),
-                    ...(linkedTaskSourceContext !== undefined ? { linkedTaskSourceContext } : {}),
-                    ...(startupDraft ? { startupDraft } : {}),
-                    ...(automationProvenanceRequest ? { automationProvenanceRequest } : {}),
-                    ...(startup
-                      ? {
-                          startupCommand: startup.command,
-                          ...(startup.env ? { startupEnv: startup.env } : {}),
-                          ...(startup.launchConfig
-                            ? { startupLaunchConfig: startup.launchConfig }
-                            : {}),
-                          ...(startup.startupCommandDelivery
-                            ? { startupCommandDelivery: startup.startupCommandDelivery }
-                            : {}),
-                          activate: true
-                        }
-                      : {})
-                  },
-                  { timeoutMs: 10 * 60_000 }
-                )
-          // Why: worktrees.onChanged can add this worktree before this callback runs; appending blindly would duplicate it (React key clash).
-          set((s) => {
-            const hostId = repoHostId(s, repoId)
-            const createdWorktree = withRepoHostOwnership(
-              result.worktree,
-              hostId,
-              getProjectHostSetupForRepoHost(s, repoId, hostId)
-            )
-            const current = s.worktreesByRepo[repoId] ?? []
-            const alreadyPresent = current.some((w) => w.id === createdWorktree.id)
-            const nextWorktrees = alreadyPresent
-              ? current.map((worktree) =>
-                  worktree.id === createdWorktree.id
-                    ? { ...worktree, ...createdWorktree }
-                    : worktree
-                )
-              : [...current, createdWorktree]
-            return {
-              worktreesByRepo: {
-                ...s.worktreesByRepo,
-                [repoId]: nextWorktrees
-              },
-              ...(result.workspaceLineage
-                ? {
-                    workspaceLineageByChildKey: {
-                      ...s.workspaceLineageByChildKey,
-                      [result.workspaceLineage.childWorkspaceKey]: result.workspaceLineage
-                    }
-                  }
-                : {}),
-              ...(result.initialBaseStatus
-                ? {
-                    baseStatusByWorktreeId: {
-                      ...s.baseStatusByWorktreeId,
-                      [result.worktree.id]:
-                        s.baseStatusByWorktreeId[result.worktree.id] ?? result.initialBaseStatus
-                    }
-                  }
-                : {}),
-              sortEpoch: s.sortEpoch + 1
-            }
-          })
+          applyCreatedWorktree(set, repoId, outcome.result)
+          const { result } = outcome
           showLocalBaseRefRefreshToast(result.localBaseRefRefresh, result.worktree)
           if (result.baseFallback) {
             requestWorktreeBaseFallbackNotice(result.baseFallback)
diff --git a/src/renderer/src/store/slices/worktrees/create/created-worktree-state-merge.ts b/src/renderer/src/store/slices/worktrees/create/created-worktree-state-merge.ts
new file mode 100644
index 00000000000..51ad88b2537
--- /dev/null
+++ b/src/renderer/src/store/slices/worktrees/create/created-worktree-state-merge.ts
@@ -0,0 +1,63 @@
+import type { WorktreeSliceSet } from '../listing/worktree-slice-types'
+import type { CreateWorktreeResult } from '../../../../../../shared/worktree/create-types'
+import {
+  getProjectHostSetupForRepoHost,
+  repoHostId,
+  withRepoHostOwnership
+} from '../listing/worktree-host-ownership'
+
+/** Folds a fresh create result into the worktree, lineage and base-status maps. */
+export function applyCreatedWorktree(
+  set: WorktreeSliceSet,
+  repoId: string,
+  result: CreateWorktreeResult
+) {
+  // Why: worktrees.onChanged can add this worktree before this callback runs; appending blindly would duplicate it (React key clash).
+  set((s) => {
+    const hostId = repoHostId(s, repoId)
+    const createdWorktree = withRepoHostOwnership(
+      result.worktree,
+      hostId,
+      getProjectHostSetupForRepoHost(s, repoId, hostId)
+    )
+    const current = s.worktreesByRepo[repoId] ?? []
+    const alreadyPresent = current.some((w) => w.id === createdWorktree.id)
+    const nextWorktrees = alreadyPresent
+      ? current.map((worktree) =>
+          worktree.id === createdWorktree.id ? { ...worktree, ...createdWorktree } : worktree
+        )
+      : [...current, createdWorktree]
+    return {
+      worktreesByRepo: {
+        ...s.worktreesByRepo,
+        [repoId]: nextWorktrees
+      },
+      ...(result.workspaceLineage
+        ? {
+            workspaceLineageByChildKey: {
+              ...s.workspaceLineageByChildKey,
+              [result.workspaceLineage.childWorkspaceKey]: result.workspaceLineage
+            }
+          }
+        : {}),
+      ...(result.lineage
+        ? {
+            worktreeLineageById: {
+              ...s.worktreeLineageById,
+              [result.lineage.worktreeId]: result.lineage
+            }
+          }
+        : {}),
+      ...(result.initialBaseStatus
+        ? {
+            baseStatusByWorktreeId: {
+              ...s.baseStatusByWorktreeId,
+              [result.worktree.id]:
+                s.baseStatusByWorktreeId[result.worktree.id] ?? result.initialBaseStatus
+            }
+          }
+        : {}),
+      sortEpoch: s.sortEpoch + 1
+    }
+  })
+}
diff --git a/src/renderer/src/store/slices/worktrees/create/worktree-create-parent-pick.ts b/src/renderer/src/store/slices/worktrees/create/worktree-create-parent-pick.ts
new file mode 100644
index 00000000000..6f378bc5a46
--- /dev/null
+++ b/src/renderer/src/store/slices/worktrees/create/worktree-create-parent-pick.ts
@@ -0,0 +1,94 @@
+import type { AppState } from '../../../types'
+import type { WorkspaceKey } from '../../../../../../shared/folder-workspace-types'
+import { toast } from 'sonner'
+import { translate } from '@/i18n/i18n'
+import { resolveWorktreeDisplayName } from '@/lib/worktree-default-display-name'
+import {
+  folderWorkspaceKey,
+  parseWorkspaceKey,
+  worktreeWorkspaceKey
+} from '../../../../../../shared/workspace-scope'
+import { getIndexedWorktreeById } from '@/store/worktree-repo-index'
+
+export type WorktreeCreateParentPick = {
+  /** Workspace the create attaches to. Undefined once a stale pick is dropped. */
+  parentWorkspace?: WorkspaceKey
+  /** Set only for an accepted user pick, whose lineage row must come back from the host. */
+  pickedParentWorktreeId?: string
+  /** Label for the drop warning; null when the parent record is already gone, '' when it has no name. */
+  pickedDisplayName: string | null
+  /** The pick no longer qualifies, so the create runs unattached. */
+  staleBeforeCreate: boolean
+}
+
+/** Resolves the composer pick against the current store, falling back to the active folder scope. */
+export function resolveWorktreeCreateParent(
+  state: AppState,
+  repoId: string,
+  requestedParentWorktreeId: string | undefined
+): WorktreeCreateParentPick {
+  const picked = requestedParentWorktreeId
+    ? getIndexedWorktreeById(state.worktreesByRepo, requestedParentWorktreeId)
+    : undefined
+  const usable = picked && !picked.isArchived && picked.repoId === repoId ? picked.id : undefined
+  const pickedDisplayName = picked ? resolveWorktreeDisplayName(picked).trim() : null
+  if (usable) {
+    return {
+      parentWorkspace: worktreeWorkspaceKey(usable),
+      pickedParentWorktreeId: usable,
+      pickedDisplayName,
+      staleBeforeCreate: false
+    }
+  }
+  const activeScope = parseWorkspaceKey(state.activeWorkspaceKey ?? '')
+  return {
+    parentWorkspace:
+      activeScope?.type === 'folder'
+        ? folderWorkspaceKey(activeScope.folderWorkspaceId)
+        : undefined,
+    pickedDisplayName,
+    staleBeforeCreate: Boolean(requestedParentWorktreeId)
+  }
+}
+
+/** Resolved late so the common create path never walks the folder-workspace list, and defensively
+ *  so a missing label can never fail a create that already succeeded. */
+function parentLabel(state: AppState, parent: WorktreeCreateParentPick): string | null {
+  // Why not truthiness: a picked-but-unnamed worktree must warn unnamed, not name the active folder.
+  if (parent.pickedDisplayName !== null) {
+    return parent.pickedDisplayName || null
+  }
+  const scope = parent.parentWorkspace ? parseWorkspaceKey(parent.parentWorkspace) : null
+  if (scope?.type !== 'folder') {
+    return null
+  }
+  const workspace = state.folderWorkspaces?.find(
+    (candidate) => candidate.id === scope.folderWorkspaceId
+  )
+  return workspace?.name.trim() || null
+}
+
+export function notifyWorktreeParentDropped(
+  state: AppState,
+  parent: WorktreeCreateParentPick
+): void {
+  const parentDisplayName = parentLabel(state, parent)
+  toast.warning(
+    parentDisplayName
+      ? translate(
+          'auto.store.slices.worktrees.createdWithoutParentNesting',
+          'Created without nesting under "{{value0}}"',
+          { value0: parentDisplayName }
+        )
+      : translate(
+          'auto.store.slices.worktrees.createdWithoutParentNestingUnnamed',
+          'Created without nesting under the selected parent'
+        ),
+    {
+      description: translate(
+        'auto.store.slices.worktrees.createdWithoutParentNestingDetail',
+        'The parent workspace was no longer available. You can set it from the workspace menu.'
+      )
+    }
+  )
+}
diff --git a/src/renderer/src/store/slices/worktrees/create/worktree-create-payload.ts b/src/renderer/src/store/slices/worktrees/create/worktree-create-payload.ts
new file mode 100644
index 00000000000..b018183016d
--- /dev/null
+++ b/src/renderer/src/store/slices/worktrees/create/worktree-create-payload.ts
@@ -0,0 +1,132 @@
+import type { CreateWorktreeArgs } from '../../../../../../shared/worktree/create-types'
+import type { ExecutionHostId } from '../../../../../../shared/execution-host'
+import type { WorkspaceKey } from '../../../../../../shared/folder-workspace-types'
+import type { TaskSourceContext } from '../../../../../../shared/task-source-context'
+import type { WorkspaceLinkedItem } from '../../../../../../shared/worktree/types'
+
+/** Trailing bag for `createWorktree` args that outgrew its positional list. */
+export type CreateWorktreeCallOptions = {
+  automationProvenanceRequest?: CreateWorktreeArgs['automationProvenanceRequest']
+  linkedWorkItem?: WorkspaceLinkedItem | null
+  linkedTaskSourceContext?: TaskSourceContext | null
+  /** Lets the owning runtime launch and prefill a task agent without first creating an idle shell. */
+  startupDraft?: string
+  /** True only when `name` came from the creature-name generator; gates host-side retirement. */
+  nameWasGenerated?: boolean
+  /** Parent picked in the composer. Sets sidebar nesting only; ignored if it no longer exists. */
+  parentWorktreeId?: string
+  provisionedRoot?: {
+    runtimeId: string
+    executionHostId: ExecutionHostId
+    expectedPath: string
+  }
+}
+
+/** Everything `createWorktree` received, packed once so both transports read from the same record.
+ *  The per-attempt fields live on `WorktreeCreateAttempt` instead. */
+export type WorktreeCreateRequest = Omit<CreateWorktreeArgs, 'parentWorkspace' | 'manualOrder'> & {
+  options?: CreateWorktreeCallOptions
+}
+
+/** Per-attempt values: names carry the conflict-retry suffix, the parent can be dropped on retry. */
+export type WorktreeCreateAttempt = {
+  name: string
+  branchNameOverride?: string
+  parentWorkspace?: WorkspaceKey
+  manualOrder?: number
+}
+
+/** Fields both transports spell the same way; one builder keeps IPC and RPC payloads from drifting. */
+function sharedCreateFields(
+  request: WorktreeCreateRequest,
+  attempt: WorktreeCreateAttempt
+): Omit<CreateWorktreeArgs, 'repoId' | 'startup' | 'creationId'> {
+  const { options } = request
+  return {
+    name: attempt.name,
+    ...(options?.nameWasGenerated ? { nameWasGenerated: true } : {}),
+    baseBranch: request.baseBranch,
+    ...(request.compareBaseRef ? { compareBaseRef: request.compareBaseRef } : {}),
+    ...(attempt.branchNameOverride ? { branchNameOverride: attempt.branchNameOverride } : {}),
+    setupDecision: request.setupDecision,
+    sparseCheckout: request.sparseCheckout,
+    ...(request.displayName ? { displayName: request.displayName } : {}),
+    ...(request.telemetrySource ? { telemetrySource: request.telemetrySource } : {}),
+    ...(request.linkedIssue !== undefined ? { linkedIssue: request.linkedIssue } : {}),
+    ...(request.linkedPR !== undefined ? { linkedPR: request.linkedPR } : {}),
+    ...(request.pushTarget ? { pushTarget: request.pushTarget } : {}),
+    ...(request.createdWithAgent ? { createdWithAgent: request.createdWithAgent } : {}),
+    ...(request.pendingFirstAgentMessageRename === true && request.createdWithAgent
+      ? { pendingFirstAgentMessageRename: true }
+      : {}),
+    ...(request.linkedLinearIssue !== undefined
+      ? { linkedLinearIssue: request.linkedLinearIssue }
+      : {}),
+    ...(request.linkedLinearIssueWorkspaceId !== undefined
+      ? { linkedLinearIssueWorkspaceId: request.linkedLinearIssueWorkspaceId }
+      : {}),
+    ...(request.linkedLinearIssueOrganizationUrlKey !== undefined
+      ? {
+          linkedLinearIssueOrganizationUrlKey: request.linkedLinearIssueOrganizationUrlKey
+        }
+      : {}),
+    ...(attempt.manualOrder !== undefined ? { manualOrder: attempt.manualOrder } : {}),
+    ...(attempt.parentWorkspace ? { parentWorkspace: attempt.parentWorkspace } : {}),
+    ...(request.workspaceStatus !== undefined ? { workspaceStatus: request.workspaceStatus } : {}),
+    ...(request.linkedGitLabMR !== undefined ? { linkedGitLabMR: request.linkedGitLabMR } : {}),
+    ...(request.linkedGitLabIssue !== undefined
+      ? { linkedGitLabIssue: request.linkedGitLabIssue }
+      : {}),
+    ...(request.linkedBitbucketPR !== undefined
+      ? { linkedBitbucketPR: request.linkedBitbucketPR }
+      : {}),
+    ...(request.linkedAzureDevOpsPR !== undefined
+      ? { linkedAzureDevOpsPR: request.linkedAzureDevOpsPR }
+      : {}),
+    ...(request.linkedGiteaPR !== undefined ? { linkedGiteaPR: request.linkedGiteaPR } : {}),
+    ...(options?.linkedWorkItem !== undefined ? { linkedWorkItem: options.linkedWorkItem } : {}),
+    ...(options?.linkedTaskSourceContext !== undefined
+      ? { linkedTaskSourceContext: options.linkedTaskSourceContext }
+      : {}),
+    ...(options?.automationProvenanceRequest
+      ? { automationProvenanceRequest: options.automationProvenanceRequest }
+      : {})
+  }
+}
+
+export function buildLocalWorktreeCreateArgs(
+  request: WorktreeCreateRequest,
+  attempt: WorktreeCreateAttempt
+): CreateWorktreeArgs {
+  return {
+    repoId: request.repoId,
+    ...sharedCreateFields(request, attempt),
+    ...(request.startup ? { startup: request.startup } : {}),
+    ...(request.creationId ? { creationId: request.creationId } : {})
+  }
+}
+
+export function buildRuntimeWorktreeCreateParams(
+  request: WorktreeCreateRequest,
+  attempt: WorktreeCreateAttempt
+): Record<string, unknown> {
+  const { startup, options } = request
+  return {
+    repo: request.repoId,
+    ...sharedCreateFields(request, attempt),
+    // Why: the host defaults a bare `parentWorkspace` to CLI provenance; app picks are manual.
+    ...(attempt.parentWorkspace ? { parentWorkspaceOrigin: 'manual' } : {}),
+    ...(options?.startupDraft ? { startupDraft: options.startupDraft } : {}),
+    ...(startup
+      ? {
+          startupCommand: startup.command,
+          ...(startup.env ? { startupEnv: startup.env } : {}),
+          ...(startup.launchConfig ? { startupLaunchConfig: startup.launchConfig } : {}),
+          ...(startup.startupCommandDelivery
+            ? { startupCommandDelivery: startup.startupCommandDelivery }
+            : {}),
+          activate: true
+        }
+      : {})
+  }
+}
diff --git a/src/renderer/src/store/slices/worktrees/listing/fetch-worktrees.ts b/src/renderer/src/store/slices/worktrees/listing/fetch-worktrees.ts
index b812ea170ac..0eaeb33345d 100644
--- a/src/renderer/src/store/slices/worktrees/listing/fetch-worktrees.ts
+++ b/src/renderer/src/store/slices/worktrees/listing/fetch-worktrees.ts
@@ -110,7 +110,7 @@ export function createFetchWorktrees(
       // Direct SSH lineage requires its own qualified authority result.
       // Bulk runtime callers apply one final host-wide snapshot after all repo merges.
       if (!directSshAuthority && !options?.suppressRemoteLineageRefresh) {
-        await refreshRemoteWorktreeLineageBestEffort(settings, set)
+        await refreshRemoteWorktreeLineageBestEffort(settings, set, get)
       }
       return directCallerAuthority ? refresh.providerResult! : refresh.result.authoritative
     } catch (err) {
diff --git a/src/renderer/src/store/slices/worktrees/listing/runtime-worktree-rpc-errors.ts b/src/renderer/src/store/slices/worktrees/listing/runtime-worktree-rpc-errors.ts
index b5cf89e47d8..d95393554a1 100644
--- a/src/renderer/src/store/slices/worktrees/listing/runtime-worktree-rpc-errors.ts
+++ b/src/renderer/src/store/slices/worktrees/listing/runtime-worktree-rpc-errors.ts
@@ -11,3 +11,9 @@ export function isRuntimeSelectorNotFoundError(error: unknown): boolean {
 export function isRuntimeRepoNotFoundError(error: unknown): boolean {
   return hasRuntimeRpcErrorCode(error, 'repo_not_found')
 }
+
+/** Thrown before the worktree exists, so the caller can safely retry without the parent.
+ *  Matches re-wrapped errors too: relay and environment transports lose the RuntimeRpcCallError. */
+export function isRuntimeLineageParentMissingError(error: unknown): boolean {
+  return hasRuntimeRpcErrorCode(error, 'LINEAGE_PARENT_NOT_FOUND')
+}
diff --git a/src/renderer/src/store/slices/worktrees/metadata/worktree-lineage-actions.ts b/src/renderer/src/store/slices/worktrees/metadata/worktree-lineage-actions.ts
index c8820f9df4c..f560f35f159 100644
--- a/src/renderer/src/store/slices/worktrees/metadata/worktree-lineage-actions.ts
+++ b/src/renderer/src/store/slices/worktrees/metadata/worktree-lineage-actions.ts
@@ -12,10 +12,11 @@ import { settingsForWorktreeOwner } from '../listing/worktree-owner-settings'
 // Why: this runs inside a catch, so letting the refresh reject would replace the failure it recovers from.
 async function refreshWorktreeLineageBestEffort(
   ownerSettings: AppState['settings'],
-  set: WorktreeSliceSet
+  set: WorktreeSliceSet,
+  get: WorktreeSliceGet
 ): Promise<void> {
   try {
-    await refreshWorktreeLineageForSettings(ownerSettings, set)
+    await refreshWorktreeLineageForSettings(ownerSettings, set, get)
   } catch (err) {
     console.error('Failed to refresh worktree lineage after a failed write:', err)
   }
@@ -41,7 +42,7 @@ export function createFetchWorktreeLineage(
       const settings = ownerSettings
         ? { ...ownerSettings, activeRuntimeEnvironmentId }
         : ({ activeRuntimeEnvironmentId } as AppState['settings'])
-      await refreshWorktreeLineageForSettings(settings, set, {
+      await refreshWorktreeLineageForSettings(settings, set, get, {
         reuseRecentCompatibilityFailure: true
       })
     } catch (err) {
@@ -66,7 +67,7 @@ export function createUpdateWorktreeLineage(
       )
     } catch (err) {
       console.error('Failed to update worktree lineage:', err)
-      await refreshWorktreeLineageBestEffort(ownerSettings, set)
+      await refreshWorktreeLineageBestEffort(ownerSettings, set, get)
       throw err
     }
   }
@@ -87,7 +88,7 @@ export function createAssignWorktreeParent(
     } catch (err) {
       console.error('Failed to assign worktree parent:', err)
       // Unlike the update path this rethrows, so the recovery refresh must not mask the original cause.
-      await refreshWorktreeLineageBestEffort(ownerSettings, set)
+      await refreshWorktreeLineageBestEffort(ownerSettings, set, get)
       throw err
     }
   }
diff --git a/src/renderer/src/store/slices/worktrees/metadata/worktree-lineage-host-merge.ts b/src/renderer/src/store/slices/worktrees/metadata/worktree-lineage-host-merge.ts
index 26470ea043d..f0c396bcecd 100644
--- a/src/renderer/src/store/slices/worktrees/metadata/worktree-lineage-host-merge.ts
+++ b/src/renderer/src/store/slices/worktrees/metadata/worktree-lineage-host-merge.ts
@@ -37,16 +37,24 @@ export function mergeLineageForHost(
     'repos' | 'settings' | 'worktreesByRepo' | 'detectedWorktreesByRepo' | 'worktreeLineageById'
   >,
   hostId: ExecutionHostId,
-  lineage: Readonly<Record<string, WorktreeLineage>>
+  lineage: Readonly<Record<string, WorktreeLineage>>,
+  lineageAtRequestStart?: Readonly<Record<string, WorktreeLineage>>
 ): Readonly<Record<string, WorktreeLineage>> {
+  // Why per-row and not just per-key: any local write that landed after this request started
+  // outranks the reply — a create, a parent reassignment, or a delete the reply would restore.
+  const writtenSinceRequestStart = (worktreeId: string): boolean =>
+    lineageAtRequestStart !== undefined &&
+    lineageAtRequestStart[worktreeId] !== state.worktreeLineageById[worktreeId]
   const next: Record<string, WorktreeLineage> = {}
   for (const [worktreeId, existing] of Object.entries(state.worktreeLineageById)) {
-    if (getWorktreeHostId(state, worktreeId) !== hostId) {
+    if (getWorktreeHostId(state, worktreeId) !== hostId || writtenSinceRequestStart(worktreeId)) {
       next[worktreeId] = existing
     }
   }
   for (const [worktreeId, incoming] of Object.entries(lineage)) {
-    next[worktreeId] = incoming
+    if (!writtenSinceRequestStart(worktreeId)) {
+      next[worktreeId] = incoming
+    }
   }
   return reuseEqualRecordMap(state.worktreeLineageById, next)
 }
@@ -61,20 +69,30 @@ export function mergeWorkspaceLineageForHost(
     | 'workspaceLineageByChildKey'
   >,
   hostId: ExecutionHostId,
-  lineage: Readonly<Record<string, WorkspaceLineage>>
+  lineage: Readonly<Record<string, WorkspaceLineage>>,
+  lineageAtRequestStart?: Readonly<Record<string, WorkspaceLineage>>
 ): Readonly<Record<string, WorkspaceLineage>> {
+  const writtenSinceRequestStart = (childKey: string): boolean =>
+    lineageAtRequestStart !== undefined &&
+    lineageAtRequestStart[childKey] !== state.workspaceLineageByChildKey[childKey]
   const next: Record<string, WorkspaceLineage> = {}
   for (const [childKey, existing] of Object.entries(state.workspaceLineageByChildKey)) {
     const childScope = parseWorkspaceKey(existing.childWorkspaceKey)
     const childHostId =
       childScope?.type === 'worktree' ? getWorktreeHostId(state, childScope.worktreeId) : null
     // A focused host refresh can no longer prove unknown-host child rows are current.
-    if (childScope?.type !== 'worktree' || (childHostId !== null && childHostId !== hostId)) {
+    if (
+      childScope?.type !== 'worktree' ||
+      (childHostId !== null && childHostId !== hostId) ||
+      writtenSinceRequestStart(childKey)
+    ) {
       next[childKey] = existing
     }
   }
   for (const [childKey, incoming] of Object.entries(lineage)) {
-    next[childKey] = incoming
+    if (!writtenSinceRequestStart(childKey)) {
+      next[childKey] = incoming
+    }
   }
   return reuseEqualRecordMap(state.workspaceLineageByChildKey, next)
 }
diff --git a/src/renderer/src/store/slices/worktrees/metadata/worktree-lineage-refresh.ts b/src/renderer/src/store/slices/worktrees/metadata/worktree-lineage-refresh.ts
index 26b68647f70..ae584253173 100644
--- a/src/renderer/src/store/slices/worktrees/metadata/worktree-lineage-refresh.ts
+++ b/src/renderer/src/store/slices/worktrees/metadata/worktree-lineage-refresh.ts
@@ -22,6 +22,21 @@ import type {
   WorktreeWithLineage
 } from '../listing/worktree-slice-types'
 
+/** Per-row baseline the reply is merged against, so any local write since then outranks it. */
+type LineageAtRequestStart = {
+  worktreeLineageById: Readonly<Record<string, WorktreeLineage>>
+  workspaceLineageByChildKey: Readonly<Record<string, WorkspaceLineage>>
+}
+
+function captureLineageAtRequestStart(
+  state: Pick<AppState, 'worktreeLineageById' | 'workspaceLineageByChildKey'>
+): LineageAtRequestStart {
+  return {
+    worktreeLineageById: state.worktreeLineageById,
+    workspaceLineageByChildKey: state.workspaceLineageByChildKey
+  }
+}
+
 export async function listWorktreeLineageForRuntime(
   settings: AppState['settings'],
   options: BackgroundRuntimeRefreshOptions = {}
@@ -206,14 +221,21 @@ export function applyHostLineageRefresh(
   lineage: {
     worktreeLineageById: Readonly<Record<string, WorktreeLineage>>
     workspaceLineageByChildKey: Readonly<Record<string, WorkspaceLineage>>
-  }
+  },
+  lineageAtRequestStart?: LineageAtRequestStart
 ): void {
   set((s) => {
-    const worktreeLineageById = mergeLineageForHost(s, hostId, lineage.worktreeLineageById)
+    const worktreeLineageById = mergeLineageForHost(
+      s,
+      hostId,
+      lineage.worktreeLineageById,
+      lineageAtRequestStart?.worktreeLineageById
+    )
     const workspaceLineageByChildKey = mergeWorkspaceLineageForHost(
       s,
       hostId,
-      lineage.workspaceLineageByChildKey
+      lineage.workspaceLineageByChildKey,
+      lineageAtRequestStart?.workspaceLineageByChildKey
     )
     if (
       worktreeLineageById === s.worktreeLineageById &&
@@ -228,24 +250,38 @@ export function applyHostLineageRefresh(
 export async function refreshWorktreeLineageForSettings(
   settings: AppState['settings'],
   set: Parameters<StateCreator<AppState>>[0],
+  getState: () => Pick<AppState, 'worktreeLineageById' | 'workspaceLineageByChildKey'>,
   options: BackgroundRuntimeRefreshOptions = {}
 ): Promise<void> {
+  const lineageAtRequestStart = captureLineageAtRequestStart(getState())
   const lineage = await listWorktreeLineageForRuntime(settings, options)
-  applyHostLineageRefresh(set, getSettingsFocusedExecutionHostId(settings), lineage)
+  applyHostLineageRefresh(
+    set,
+    getSettingsFocusedExecutionHostId(settings),
+    lineage,
+    lineageAtRequestStart
+  )
 }
 
 export async function refreshRemoteWorktreeLineageBestEffort(
   settings: AppState['settings'],
-  set: (partial: Partial<AppState> | ((state: AppState) => Partial<AppState>)) => void
+  set: (partial: Partial<AppState> | ((state: AppState) => Partial<AppState>)) => void,
+  getState: () => Pick<AppState, 'worktreeLineageById' | 'workspaceLineageByChildKey'>
 ): Promise<void> {
   if (getActiveRuntimeTarget(settings).kind === 'local') {
     return
   }
   try {
+    const lineageAtRequestStart = captureLineageAtRequestStart(getState())
     const lineage = await listWorktreeLineageForRuntime(settings, {
       reuseRecentCompatibilityFailure: true
     })
-    applyHostLineageRefresh(set, getSettingsFocusedExecutionHostId(settings), lineage)
+    applyHostLineageRefresh(
+      set,
+      getSettingsFocusedExecutionHostId(settings),
+      lineage,
+      lineageAtRequestStart
+    )
   } catch (err) {
     // Why: lineage is supplemental, so a remote timeout here must not discard a successful worktree refresh.
     console.error('Failed to fetch worktree lineage:', err)
diff --git a/src/renderer/src/web/preload-api/web-runtime-calls.ts b/src/renderer/src/web/preload-api/web-runtime-calls.ts
index 4470b0be37a..16bc514074a 100644
--- a/src/renderer/src/web/preload-api/web-runtime-calls.ts
+++ b/src/renderer/src/web/preload-api/web-runtime-calls.ts
@@ -78,7 +78,9 @@ export async function callRuntimeResult<TResult>(
 ): Promise<TResult> {
   const response = await callRuntimeEnvelope(method, params, timeoutMs)
   if (!response.ok) {
-    throw new Error(response.error.message)
+    // Why keep the code: callers classify recoverable host failures by token, and the message alone
+    // (e.g. "Parent selector was not found.") carries none.
+    throw Object.assign(new Error(response.error.message), { code: response.error.code })
   }
   return response.result as TResult
 }
diff --git a/src/renderer/src/web/preload-api/web-worktrees-api.ts b/src/renderer/src/web/preload-api/web-worktrees-api.ts
index 5d3b9bd1bd9..43e496d3bd0 100644
--- a/src/renderer/src/web/preload-api/web-worktrees-api.ts
+++ b/src/renderer/src/web/preload-api/web-worktrees-api.ts
@@ -86,6 +86,8 @@ export function createWorktreesApi(): NonNullable<Partial<PreloadApi>['worktrees
             }
           : {}),
         parentWorkspace: args.parentWorkspace,
+        // Why: every create through this API is an in-app action, never the CLI's parent flag.
+        ...(args.parentWorkspace ? { parentWorkspaceOrigin: 'manual' } : {}),
         workspaceStatus: args.workspaceStatus,
         manualOrder: args.manualOrder,
         automationProvenanceRequest: args.automationProvenanceRequest
diff --git a/src/renderer/src/web/web-preload-api-workspace-catalog.test.ts b/src/renderer/src/web/web-preload-api-workspace-catalog.test.ts
index cb6ca0eb3e8..60efde1d826 100644
--- a/src/renderer/src/web/web-preload-api-workspace-catalog.test.ts
+++ b/src/renderer/src/web/web-preload-api-workspace-catalog.test.ts
@@ -677,6 +677,49 @@ describe('web worktree preload API', () => {
     expect(runtimeCalls[0]?.params).not.toHaveProperty('nameWasGenerated')
   })
 
+  // Why: without it the host records the app's parent pick as a CLI flag, which cleans up differently.
+  it('marks a parent-picked create as a manual action', async () => {
+    const runtimeCalls: { method: string; params: unknown }[] = []
+    vi.doMock('./web-runtime-client', () => ({
+      WebRuntimeClient: class {
+        call(method: string, params?: unknown): Promise<RuntimeRpcResponse<unknown>> {
+          runtimeCalls.push({ method, params })
+          return Promise.resolve({
+            id: `call-${runtimeCalls.length}`,
+            ok: true,
+            result: { worktree: { id: 'repo-1::/workspace/child', path: '/workspace/child' } },
+            _meta: { runtimeId: 'runtime-1' }
+          })
+        }
+
+        close(): void {}
+      }
+    }))
+
+    const globals = installBrowserGlobals('Linux')
+    writeStoredRuntimeEnvironment(globals.storage)
+    const { installWebPreloadApi } = await import('./web-preload-api')
+    installWebPreloadApi()
+
+    await globals.window.api.worktrees.create({
+      repoId: 'repo-1',
+      name: 'child',
+      setupDecision: 'inherit'
+    })
+    await globals.window.api.worktrees.create({
+      repoId: 'repo-1',
+      name: 'child',
+      setupDecision: 'inherit',
+      parentWorkspace: 'folder:folder-1'
+    })
+
+    expect(runtimeCalls[0]?.params).not.toHaveProperty('parentWorkspaceOrigin')
+    expect(runtimeCalls[1]?.params).toMatchObject({
+      parentWorkspace: 'folder:folder-1',
+      parentWorkspaceOrigin: 'manual'
+    })
+  })
+
   it('encodes explicit push target clears for runtime worktree updates', async () => {
     const runtimeCalls: { method: string; params: unknown }[] = []
     vi.doMock('./web-runtime-client', () => ({
diff --git a/src/shared/resolved-worktree-lineage.test.ts b/src/shared/resolved-worktree-lineage.test.ts
index 1c8803d28dd..44f38e41e1e 100644
--- a/src/shared/resolved-worktree-lineage.test.ts
+++ b/src/shared/resolved-worktree-lineage.test.ts
@@ -2,7 +2,11 @@ import { describe, expect, it } from 'vitest'
 import { join } from 'node:path'
 import type { WorktreeLineage } from './worktree/lineage-types'
 import type { Worktree } from './worktree/types'
-import { projectResolvedWorktreeLineage } from './resolved-worktree-lineage'
+import type { WorktreeLineageBoundary } from './resolved-worktree-lineage'
+import {
+  projectResolvedWorktreeLineage,
+  sharesWorktreeLineageBoundary
+} from './resolved-worktree-lineage'
 
 function worktree(id: string, instanceId: string, overrides: Partial<Worktree> = {}): Worktree {
   return {
@@ -41,6 +45,41 @@ function lineage(overrides: Partial<WorktreeLineage> = {}): WorktreeLineage {
   }
 }
 
+describe('sharesWorktreeLineageBoundary', () => {
+  const boundary = (overrides: Partial<WorktreeLineageBoundary> = {}): WorktreeLineageBoundary => ({
+    repoId: 'repo',
+    hostId: 'local',
+    projectId: 'github:stablyai/orca',
+    ...overrides
+  })
+
+  it('accepts an identical repo, host, and project', () => {
+    expect(sharesWorktreeLineageBoundary(boundary(), boundary())).toBe(true)
+  })
+
+  it('rejects a differing repo even when host and project agree', () => {
+    expect(sharesWorktreeLineageBoundary(boundary(), boundary({ repoId: 'other-repo' }))).toBe(
+      false
+    )
+  })
+
+  it.each([
+    ['child host', boundary({ hostId: undefined }), boundary()],
+    ['parent host', boundary(), boundary({ hostId: undefined })],
+    ['child project', boundary({ projectId: undefined }), boundary()],
+    ['parent project', boundary(), boundary({ projectId: undefined })]
+  ])('treats an undefined %s as compatible', (_label, child, parent) => {
+    expect(sharesWorktreeLineageBoundary(child, parent)).toBe(true)
+  })
+
+  it.each([
+    ['host', boundary({ hostId: 'ssh:remote' })],
+    ['project', boundary({ projectId: 'github:other/project' })]
+  ])('rejects a defined %s mismatch', (_label, parent) => {
+    expect(sharesWorktreeLineageBoundary(boundary(), parent)).toBe(false)
+  })
+})
+
 describe('projectResolvedWorktreeLineage', () => {
   const parent = worktree('parent', 'parent-instance')
   const child = worktree('child', 'child-instance')
diff --git a/src/shared/resolved-worktree-lineage.ts b/src/shared/resolved-worktree-lineage.ts
index f0a50ae2266..01e84971273 100644
--- a/src/shared/resolved-worktree-lineage.ts
+++ b/src/shared/resolved-worktree-lineage.ts
@@ -7,7 +7,14 @@ export type WorktreeWithResolvedLineage<T extends Worktree = Worktree> = T & {
   lineage: WorktreeLineage | null
 }
 
-export function sharesResolvedWorktreeLineageBoundary(child: Worktree, parent: Worktree): boolean {
+/** The fields a lineage edge is scoped by. Split out so create-time callers — which have a
+ *  projected child, not a real Worktree — can check the same rule the projection enforces. */
+export type WorktreeLineageBoundary = Pick<Worktree, 'repoId' | 'hostId' | 'projectId'>
+
+export function sharesWorktreeLineageBoundary(
+  child: WorktreeLineageBoundary,
+  parent: WorktreeLineageBoundary
+): boolean {
   return (
     child.repoId === parent.repoId &&
     (child.hostId === undefined || parent.hostId === undefined || child.hostId === parent.hostId) &&
@@ -17,6 +24,10 @@ export function sharesResolvedWorktreeLineageBoundary(child: Worktree, parent: W
   )
 }
 
+export function sharesResolvedWorktreeLineageBoundary(child: Worktree, parent: Worktree): boolean {
+  return sharesWorktreeLineageBoundary(child, parent)
+}
+
 export function isValidResolvedWorktreeLineageEdge(
   child: Worktree,
   parent: Worktree,
diff --git a/tests/e2e/helpers/docker-ssh-relay-connection.ts b/tests/e2e/helpers/docker-ssh-relay-connection.ts
index 53fca0dbb0c..a17ad916e66 100644
--- a/tests/e2e/helpers/docker-ssh-relay-connection.ts
+++ b/tests/e2e/helpers/docker-ssh-relay-connection.ts
@@ -16,6 +16,13 @@ type DockerSshRelayConnectionOptions = {
   relayGracePeriodSeconds?: number
   remotePath?: string
   viaProxyJump?: boolean
+  /**
+   * Seed a terminal tab when the worktree has none. Default true.
+   *
+   * Why it is optional: a spec asking whether the PRODUCT adds a tab cannot tell this helper's
+   * tab from the one under test, so it must be able to leave the worktree empty.
+   */
+  seedInitialTab?: boolean
 }
 
 export async function connectDockerSshRelayTarget(
@@ -24,7 +31,7 @@ export async function connectDockerSshRelayTarget(
   options: DockerSshRelayConnectionOptions = {}
 ): Promise<ConnectedDockerSshRelayTarget> {
   return page.evaluate(
-    async ({ target, remotePath, relayGracePeriodSeconds, viaProxyJump }) => {
+    async ({ target, remotePath, relayGracePeriodSeconds, viaProxyJump, seedInitialTab }) => {
       const store = window.__store
       if (!store) {
         throw new Error('Store unavailable')
@@ -147,7 +154,7 @@ export async function connectDockerSshRelayTarget(
           throw new Error(`No remote worktree found for ${result.repo.path}`)
         }
         store.getState().setActiveWorktree(worktree.id)
-        if ((store.getState().tabsByWorktree[worktree.id] ?? []).length === 0) {
+        if (seedInitialTab && (store.getState().tabsByWorktree[worktree.id] ?? []).length === 0) {
           store.getState().createTab(worktree.id)
         }
         store.getState().setActiveTabType('terminal')
@@ -168,6 +175,7 @@ export async function connectDockerSshRelayTarget(
           ? DOCKER_SSH_PROXY_JUMP_REMOTE_REPO_PATH
           : DOCKER_SSH_RELAY_REMOTE_REPO_PATH),
       viaProxyJump: options.viaProxyJump ?? false,
+      seedInitialTab: options.seedInitialTab ?? true,
       relayGracePeriodSeconds: options.relayGracePeriodSeconds ?? 1
     }
   )
diff --git a/tests/e2e/helpers/docker-ssh-relay-terminal-tabs.ts b/tests/e2e/helpers/docker-ssh-relay-terminal-tabs.ts
new file mode 100644
index 00000000000..4ed1731e1d2
--- /dev/null
+++ b/tests/e2e/helpers/docker-ssh-relay-terminal-tabs.ts
@@ -0,0 +1,38 @@
+import { expect, type Page } from '@stablyai/playwright-test'
+
+import { waitForActivePanePtyId, waitForActiveTerminalManager } from './terminal'
+
+/** Add one more terminal tab to a connected remote worktree and wait for it to own a PTY. */
+export async function createRemoteTerminalTab(page: Page, worktreeId: string): Promise<void> {
+  const tabId = await page.evaluate((id) => {
+    const state = window.__store?.getState()
+    if (!state) {
+      throw new Error('Store unavailable')
+    }
+    const tab = state.createTab(id, undefined, undefined, { activate: true })
+    state.setActiveTab(tab.id)
+    state.setActiveTabType('terminal')
+    return tab.id
+  }, worktreeId)
+  await expect
+    .poll(() => page.evaluate(() => window.__store?.getState().activeTabId ?? null), {
+      timeout: 10_000
+    })
+    .toBe(tabId)
+  await waitForActiveTerminalManager(page, 60_000)
+  await waitForActivePanePtyId(page, 60_000)
+}
+
+export async function readRemoteTerminalTabs(
+  page: Page,
+  worktreeId: string
+): Promise<{ id: string; ptyId: string | null }[]> {
+  return page.evaluate(
+    (id) =>
+      (window.__store?.getState().tabsByWorktree[id] ?? []).map((tab) => ({
+        id: tab.id,
+        ptyId: tab.ptyId
+      })),
+    worktreeId
+  )
+}
diff --git a/tests/e2e/ssh-cold-activation-restore.spec.ts b/tests/e2e/ssh-cold-activation-restore.spec.ts
index f49ad210c0b..844074c092f 100644
--- a/tests/e2e/ssh-cold-activation-restore.spec.ts
+++ b/tests/e2e/ssh-cold-activation-restore.spec.ts
@@ -1,4 +1,4 @@
-import type { ElectronApplication, Page } from '@stablyai/playwright-test'
+import type { ElectronApplication } from '@stablyai/playwright-test'
 import { test, expect } from './helpers/orca-app'
 import { waitForActiveWorktree, waitForSessionReady } from './helpers/store'
 import {
@@ -6,6 +6,10 @@ import {
   waitForActivePanePtyId,
   waitForActiveTerminalManager
 } from './helpers/terminal'
+import {
+  createRemoteTerminalTab,
+  readRemoteTerminalTabs
+} from './helpers/docker-ssh-relay-terminal-tabs'
 import {
   cleanupDockerSshRelayTarget,
   DOCKER_SSH_RELAY_REMOTE_REPO_PATH,
@@ -21,40 +25,6 @@ const TAB_COUNT = 6
 
 test.use({ seedTestRepo: false })
 
-async function createRemoteTerminalTab(page: Page, worktreeId: string): Promise<void> {
-  const tabId = await page.evaluate((id) => {
-    const state = window.__store?.getState()
-    if (!state) {
-      throw new Error('Store unavailable')
-    }
-    const tab = state.createTab(id, undefined, undefined, { activate: true })
-    state.setActiveTab(tab.id)
-    state.setActiveTabType('terminal')
-    return tab.id
-  }, worktreeId)
-  await expect
-    .poll(() => page.evaluate(() => window.__store?.getState().activeTabId ?? null), {
-      timeout: 10_000
-    })
-    .toBe(tabId)
-  await waitForActiveTerminalManager(page, 60_000)
-  await waitForActivePanePtyId(page, 60_000)
-}
-
-async function readRemoteTerminalTabs(
-  page: Page,
-  worktreeId: string
-): Promise<{ id: string; ptyId: string | null }[]> {
-  return page.evaluate(
-    (id) =>
-      (window.__store?.getState().tabsByWorktree[id] ?? []).map((tab) => ({
-        id: tab.id,
-        ptyId: tab.ptyId
-      })),
-    worktreeId
-  )
-}
-
 function readRemoteProof(target: DockerSshRelayTarget, path: string): string | null {
   try {
     return execDockerSshRelayTargetCommand(target, `cat ${path}`)
diff --git a/tests/e2e/ssh-reconnect-tab-destruction.spec.ts b/tests/e2e/ssh-reconnect-tab-destruction.spec.ts
index 95d46a36187..c6e3a393347 100644
--- a/tests/e2e/ssh-reconnect-tab-destruction.spec.ts
+++ b/tests/e2e/ssh-reconnect-tab-destruction.spec.ts
@@ -85,12 +85,12 @@ test.describe('SSH reconnect tab destruction', () => {
       await openTerminalTabInActiveGroup(orcaPage)
       // Only that the tab exists in the store — no waiting for its manager or PTY. Every wait here
       // is time the debounced upload can use to land, which is what made this spec miss the bug.
-      const tabsBefore = await orcaPage.evaluate(() => {
+      const tabIdsBefore = await orcaPage.evaluate(() => {
         const state = window.__store?.getState()
         const worktreeId = state?.activeWorktreeId
-        return worktreeId ? (state?.tabsByWorktree?.[worktreeId]?.length ?? 0) : 0
+        return worktreeId ? (state?.tabsByWorktree?.[worktreeId] ?? []).map((tab) => tab.id) : []
       })
-      expect(tabsBefore).toBeGreaterThanOrEqual(2)
+      expect(tabIdsBefore.length).toBeGreaterThanOrEqual(2)
 
       // Deliberately NOTHING between creating the tab and reconnecting. The destruction only fires
       // while the tab's creation is still unuploaded, so idling here — as waiting for a TUI to draw
@@ -101,19 +101,26 @@ test.describe('SSH reconnect tab destruction', () => {
 
       // Checked BEFORE any paint assertion: survival and repaint are different failures, and this
       // order names which one broke instead of collapsing both into "no output".
-      const tabCounts = await orcaPage.evaluate(() => {
+      const tabState = await orcaPage.evaluate(() => {
         const state = window.__store?.getState()
         const worktreeId = state?.activeWorktreeId
         return {
-          inSlice: worktreeId ? (state?.tabsByWorktree?.[worktreeId]?.length ?? 0) : 0,
+          tabIds: worktreeId
+            ? (state?.tabsByWorktree?.[worktreeId] ?? []).map((tab) => tab.id)
+            : [],
           // __paneManagers is a Map. Object.keys on a Map silently returns [], which reads as
           // "nothing is mounted" regardless of the truth — that cost a full debugging cycle.
           paneManagers: window.__paneManagers?.size ?? 0
         }
       })
-      expect(tabCounts.inSlice, 'the reconnect destroyed the tab').toBeGreaterThanOrEqual(2)
+      // The exact set, not a lower bound: `>= 2` passes just as happily on a reconnect that ADDS a
+      // tab as on one that keeps it, so it could never fail on the accumulation half of this bug.
       expect(
-        tabCounts.paneManagers,
+        tabState.tabIds.slice().sort(),
+        'the reconnect changed the tab set: it destroyed a tab or spuriously added one'
+      ).toEqual(tabIdsBefore.slice().sort())
+      expect(
+        tabState.paneManagers,
         'the tab survived but its pane manager did not'
       ).toBeGreaterThanOrEqual(1)
 
diff --git a/tests/e2e/ssh-restart-tab-accumulation.spec.ts b/tests/e2e/ssh-restart-tab-accumulation.spec.ts
new file mode 100644
index 00000000000..cd0a314bfbd
--- /dev/null
+++ b/tests/e2e/ssh-restart-tab-accumulation.spec.ts
@@ -0,0 +1,257 @@
+import type { ElectronApplication, Page, TestInfo } from '@stablyai/playwright-test'
+import { test, expect } from './helpers/orca-app'
+import { waitForActiveWorktree, waitForSessionReady } from './helpers/store'
+import { waitForActivePanePtyId, waitForActiveTerminalManager } from './helpers/terminal'
+import { createRemoteTerminalTab } from './helpers/docker-ssh-relay-terminal-tabs'
+import {
+  cleanupDockerSshRelayTarget,
+  startDockerSshRelayTarget,
+  type DockerSshRelayTarget
+} from './helpers/docker-ssh-relay-target'
+import { connectDockerSshRelayTarget } from './helpers/docker-ssh-relay-connection'
+import { createRestartSession } from './helpers/orca-restart'
+
+const RUN_DOCKER_SSH = process.env.ORCA_E2E_SSH_DOCKER === '1'
+const RESTART_CYCLES = 3
+/** Consecutive agreeing samples that count as "the strip stopped changing". */
+const SETTLED_SAMPLES = 3
+
+test.use({ seedTestRepo: false })
+
+type WorkspaceTabSnapshot = {
+  /** Terminal tabs the store owns for the remote worktree. */
+  worktreeTabIds: string[]
+  /** Tabs the strip actually renders — what the user counts. */
+  stripTabIds: string[]
+  /** Why: a restart that re-adds the worktree under a new id would grow the window without growing the row above. */
+  totalTabCount: number
+  remoteWorktreeCount: number
+}
+
+async function readWorkspaceTabSnapshot(
+  page: Page,
+  worktreeId: string,
+  repoId: string
+): Promise<WorkspaceTabSnapshot> {
+  const store = await page.evaluate(
+    ({ worktreeId, repoId }) => {
+      const state = window.__store?.getState()
+      if (!state) {
+        throw new Error('Store unavailable')
+      }
+      return {
+        worktreeTabIds: (state.tabsByWorktree[worktreeId] ?? []).map((tab) => tab.id),
+        totalTabCount: Object.values(state.tabsByWorktree).reduce(
+          (total, tabs) => total + tabs.length,
+          0
+        ),
+        remoteWorktreeCount: (state.worktreesByRepo[repoId] ?? []).length
+      }
+    },
+    { worktreeId, repoId }
+  )
+  const stripTabIds = await page
+    .locator('.terminal-tab-strip [data-tab-id]')
+    .evaluateAll((elements) =>
+      elements.map((element) => (element as HTMLElement).dataset.tabId ?? '')
+    )
+  return { ...store, stripTabIds }
+}
+
+/**
+ * Sample the workspace until its tabs stop changing.
+ *
+ * Why: restore is not one event — the session rehydrates, then the relay reconnects, then worktree
+ * activation runs. A tab spawned by the last of those is invisible to a snapshot taken after the
+ * first, so sampling too early would let an accumulation bug pass.
+ */
+async function waitForSettledWorkspaceTabs(
+  page: Page,
+  worktreeId: string,
+  repoId: string
+): Promise<WorkspaceTabSnapshot> {
+  let latest: WorkspaceTabSnapshot = {
+    worktreeTabIds: [],
+    stripTabIds: [],
+    totalTabCount: 0,
+    remoteWorktreeCount: 0
+  }
+  let previousKey = ''
+  let agreements = 0
+  await expect
+    .poll(
+      async () => {
+        latest = await readWorkspaceTabSnapshot(page, worktreeId, repoId)
+        const key = JSON.stringify(latest)
+        agreements = key === previousKey ? agreements + 1 : 0
+        previousKey = key
+        return agreements
+      },
+      {
+        timeout: 60_000,
+        intervals: [1_000],
+        message: 'the remote workspace tab set never stopped changing'
+      }
+    )
+    .toBeGreaterThanOrEqual(SETTLED_SAMPLES)
+  return latest
+}
+
+async function waitForRestoredRemoteWorktree(
+  page: Page,
+  targetId: string,
+  worktreeId: string
+): Promise<void> {
+  await waitForSessionReady(page, 60_000)
+  await expect.poll(() => waitForActiveWorktree(page), { timeout: 60_000 }).toBe(worktreeId)
+  await expect
+    .poll(
+      () =>
+        page.evaluate(
+          (id) => window.__store?.getState().sshConnectionStates.get(id)?.status,
+          targetId
+        ),
+      { timeout: 90_000, message: 'renderer SSH state did not restore' }
+    )
+    .toBe('connected')
+  await waitForActiveTerminalManager(page, 60_000)
+  await waitForActivePanePtyId(page, 60_000)
+}
+
+/** Quit through the same beforeunload flush a real window close performs, then prove it landed. */
+async function flushSessionBeforeQuit(
+  page: Page,
+  targetId: string,
+  worktreeId: string,
+  tabIds: string[]
+): Promise<void> {
+  await page.evaluate(() => window.dispatchEvent(new Event('beforeunload')))
+  await expect
+    .poll(
+      () =>
+        page.evaluate(
+          async ({ targetId, worktreeId, tabIds }) => {
+            const persisted = await window.api.session.get()
+            const persistedIds = new Set(
+              (persisted.tabsByWorktree[worktreeId] ?? []).map((tab) => tab.id)
+            )
+            return (
+              persisted.activeConnectionIdsAtShutdown?.includes(targetId) === true &&
+              tabIds.every((tabId) => persistedIds.has(tabId))
+            )
+          },
+          { targetId, worktreeId, tabIds }
+        ),
+      { timeout: 15_000, message: 'SSH tabs and active target were not persisted before quit' }
+    )
+    .toBe(true)
+}
+
+function describeGrowth(baseline: WorkspaceTabSnapshot, cycles: WorkspaceTabSnapshot[]): string {
+  const baselineTabIds = new Set(baseline.worktreeTabIds)
+  const perCycle = cycles.map((cycle, index) => {
+    const added = cycle.worktreeTabIds.filter((tabId) => !baselineTabIds.has(tabId))
+    const suffix = added.length > 0 ? ` (+${added.length}: ${added.join(', ')})` : ''
+    return `restart${index + 1}=${cycle.worktreeTabIds.length}${suffix}/strip${cycle.stripTabIds.length}/all${cycle.totalTabCount}/worktrees${cycle.remoteWorktreeCount}`
+  })
+  return `baseline=${baseline.worktreeTabIds.length}/strip${baseline.stripTabIds.length}/all${baseline.totalTabCount}/worktrees${baseline.remoteWorktreeCount} ${perCycle.join(' ')}`
+}
+
+async function runRestartCycles(testInfo: TestInfo, initialTabCount: number): Promise<void> {
+  const restart = createRestartSession(testInfo)
+  let target: DockerSshRelayTarget | null = null
+  let app: ElectronApplication | null = null
+  try {
+    target = startDockerSshRelayTarget(testInfo)
+    const firstLaunch = await restart.launch()
+    app = firstLaunch.app
+    let page = firstLaunch.page
+    await waitForSessionReady(page)
+    const remote = await connectDockerSshRelayTarget(page, target)
+    await expect
+      .poll(() => waitForActiveWorktree(page), { timeout: 30_000 })
+      .toBe(remote.worktreeId)
+    await waitForActiveTerminalManager(page, 60_000)
+    await waitForActivePanePtyId(page, 60_000)
+
+    while (
+      (await readWorkspaceTabSnapshot(page, remote.worktreeId, remote.repoId)).worktreeTabIds
+        .length < initialTabCount
+    ) {
+      await createRemoteTerminalTab(page, remote.worktreeId)
+    }
+    const baseline = await waitForSettledWorkspaceTabs(page, remote.worktreeId, remote.repoId)
+    expect(baseline.worktreeTabIds).toHaveLength(initialTabCount)
+    expect(baseline.stripTabIds.slice().sort()).toEqual(baseline.worktreeTabIds.slice().sort())
+
+    // Why: every cycle runs before anything is asserted, so a failure reports whether the strip
+    // grows by one per restart or duplicates wholesale — those have different causes.
+    const cycles: WorkspaceTabSnapshot[] = []
+    for (let cycle = 0; cycle < RESTART_CYCLES; cycle += 1) {
+      await flushSessionBeforeQuit(
+        page,
+        remote.targetId,
+        remote.worktreeId,
+        baseline.worktreeTabIds
+      )
+      await restart.close(app)
+      app = null
+      const relaunch = await restart.launch()
+      app = relaunch.app
+      page = relaunch.page
+      await waitForRestoredRemoteWorktree(page, remote.targetId, remote.worktreeId)
+      cycles.push(await waitForSettledWorkspaceTabs(page, remote.worktreeId, remote.repoId))
+    }
+
+    const growth = describeGrowth(baseline, cycles)
+    expect(
+      cycles.map((cycle) => cycle.stripTabIds.length),
+      `tab strip grew across restarts: ${growth}`
+    ).toEqual(Array.from({ length: RESTART_CYCLES }, () => initialTabCount))
+    expect(
+      cycles.map((cycle) => cycle.totalTabCount),
+      `total tab count grew across restarts: ${growth}`
+    ).toEqual(cycles.map(() => baseline.totalTabCount))
+    expect(
+      cycles.map((cycle) => cycle.remoteWorktreeCount),
+      `the remote repo gained worktree rows across restarts: ${growth}`
+    ).toEqual(cycles.map(() => baseline.remoteWorktreeCount))
+    const expectedTabIds = baseline.worktreeTabIds.slice().sort()
+    for (const [index, cycle] of cycles.entries()) {
+      expect(cycle.worktreeTabIds.slice().sort(), `restart ${index + 1}: ${growth}`).toEqual(
+        expectedTabIds
+      )
+      expect(
+        cycle.stripTabIds.slice().sort(),
+        `restart ${index + 1} rendered different tabs: ${growth}`
+      ).toEqual(expectedTabIds)
+    }
+  } finally {
+    if (app) {
+      await restart.close(app)
+    }
+    await restart.dispose()
+    cleanupDockerSshRelayTarget(target)
+  }
+}
+
+test.describe('SSH restart tab accumulation', () => {
+  test.skip(!RUN_DOCKER_SSH, 'Set ORCA_E2E_SSH_DOCKER=1 to run Docker-backed SSH tests.')
+  test.skip(process.platform === 'win32', 'Docker SSH restore uses POSIX SSH tooling.')
+
+  // Why three restarts and not one: a single restart only proves one restore was clean. Users reach
+  // this by returning to the same SSH workspace day after day, so the invariant worth pinning is
+  // that N restarts add nothing — one spurious tab per launch is invisible to a one-shot test.
+  test('keeps a single restored SSH tab across repeated quit and relaunch cycles', async (// oxlint-disable-next-line no-empty-pattern -- This restart test owns every Electron launch.
+  {}, testInfo) => {
+    test.setTimeout(600_000)
+    await runRestartCycles(testInfo, 1)
+  })
+
+  // Why a second size: separates "one spurious default tab per restart" from "the set duplicates".
+  test('keeps every restored SSH tab across repeated quit and relaunch cycles', async (// oxlint-disable-next-line no-empty-pattern -- This restart test owns every Electron launch.
+  {}, testInfo) => {
+    test.setTimeout(600_000)
+    await runRestartCycles(testInfo, 3)
+  })
+})