fix(renderer): keep OpenCode OC| reclaim durable under launch ownership

Native OC| titles reclaim and stay OpenCode after process observation, with
sidebar title-derived rows matching tab identity. Nested Claude/Codex still
fenced while launch is active (#13341).

src/renderer/src/components/sidebar/worktree-title-derived-agent-rows.test.ts

@@ -239,6 +239,21 @@ describe('buildTitleDerivedAgentRows', () => {
     expect(rows.map((row) => [row.agentType, row.state])).toEqual([['claude', 'working']])
   })
 
+  // Why (#8478): native OC| under a non-OpenCode launch matches tab-agent reclaim (sidebar parity).
+  it('lets a native OpenCode title own the row under an active Claude launch', () => {
+    const rows = buildWorktreeAgentRows({
+      tabs: [makeTab('tab-1', { launchAgent: 'claude' })],
+      entries: [],
+      retained: [],
+      runtimePaneTitlesByTabId: { 'tab-1': { 1: 'OC | Greeting' } },
+      ptyIdsByTabId: { 'tab-1': ['pty-opencode'] },
+      terminalLayoutsByTabId: { 'tab-1': makeSingleLayout(LEAF_ID_1) },
+      now: 2000
+    })
+
+    expect(rows.map((row) => [row.agentType, row.state])).toEqual([['opencode', 'idle']])
+  })
+
   it('produces no row for a spinner-only title when the tab has no launch identity', () => {
     const rows = buildWorktreeAgentRows({
       tabs: [makeTab('tab-1')],

src/renderer/src/components/sidebar/worktree-title-derived-agent-rows.ts

@@ -20,6 +20,7 @@ import {
   resolveCompatibleAgentTypeForOwner
 } from '../../../../shared/agent-title-owner'
 import { resolvePaneAgentOwner } from '../../../../shared/pane-agent-owner'
+import { isOpenCodeNativeTitle } from '../../../../shared/opencode-terminal-title'
 
 const EMPTY_RUNTIME_TITLES: Record<string, Record<number, string>> = {}
 const EMPTY_LIVE_PTY_IDS: Record<string, string[]> = {}
@@ -213,6 +214,10 @@ export function resolveTitleDerivedAgentType(
     }
     return agentType
   }
+  // Why (#8478): native OC| is provider identity (pane reuse), not a nested child — match tab-agent.
+  if (agentType === 'opencode' && isOpenCodeNativeTitle(title)) {
+    return agentType
+  }
   // Why (#13341): nested child titles keep the durable owner until launch clears.
   if (owner && agentType !== 'unknown' && agentType !== owner) {
     return null

src/renderer/src/lib/tab-agent-from-signals.ts

@@ -114,15 +114,6 @@ export function resolveTabAgentFromSignals(args: {
     processShellForeground: args.processShellForeground
   })
   const activeLaunchAgent = launchedAgentExited ? null : launchAgent
-  // Why: re-own the foreground process within its title-identity group so OMP's nested pi (shell → omp → pi) can't flip an OMP-owned tab's icon.
-  const processAgentRaw = resolveSignalAgentForLaunchOwner(args.processAgent, owner)
-  // Why (#13341): Claude↔Codex nested CLIs become the local foreground process while the
-  // parent session still owns the pane. Do not let that child process rebrand the icon
-  // until launch ownership has exited (then process may name a genuine reuse).
-  const processAgent =
-    activeLaunchAgent && processAgentRaw && processAgentRaw !== activeLaunchAgent
-      ? null
-      : processAgentRaw
 
   // Title carries identity only as a reuse override (names a DIFFERENT-group agent) or a legacy standalone id when no hook — same-group titles say nothing (OMP wraps Pi), so the record wins.
   const explicitTitleAgent = resolveSignalAgentForLaunchOwner(
@@ -131,38 +122,49 @@ export function resolveTabAgentFromSignals(args: {
   )
   const priorIdentity = idleFocusedIdentity ?? activeLaunchAgent
   const nativeOpenCodeTitle = explicitTitleAgent === 'opencode' && isOpenCodeNativeTitle(args.title)
+  // Why (#8478): native `OC |` is provider identity for pane reuse — durable while the frame
+  // remains, including after process observation and under a non-OpenCode launch (#13341 still
+  // fences other cross-group nested titles/processes).
+  const openCodeNativeReclaim =
+    nativeOpenCodeTitle &&
+    (activeLaunchAgent === null || activeLaunchAgent !== 'opencode') &&
+    (priorIdentity === null || priorIdentity !== 'opencode')
+  // Why: re-own the foreground process within its title-identity group so OMP's nested pi (shell → omp → pi) can't flip an OMP-owned tab's icon.
+  const processAgentRaw = resolveSignalAgentForLaunchOwner(args.processAgent, owner)
+  // Why (#13341): Claude↔Codex nested CLIs become the local foreground process while the
+  // parent session still owns the pane. Do not let that child process rebrand the icon
+  // until launch ownership has exited (then process may name a genuine reuse).
+  // Why (#8478): after OC| reclaim, a launch-matching process must not undo OpenCode.
+  const processAgent =
+    openCodeNativeReclaim && processAgentRaw && processAgentRaw !== 'opencode'
+      ? null
+      : activeLaunchAgent && processAgentRaw && processAgentRaw !== activeLaunchAgent
+        ? null
+        : processAgentRaw
   // Why: a "claude" token in another agent's task text is a mention, not identity, so it must
   // not take a pane from its known owner — only a title that PRESENTS Claude may (#8940).
   const titleClaimsIdentity =
     explicitTitleAgent !== 'claude' || isClaudeIdentityFrameTitle(args.title)
-  // Why: native OpenCode titles can reclaim stale launch intent before any observed hook signal.
-  // Why (#13341): once a launch owner is still active, a nested child's title is not pane reuse.
+  // Why (#13341): nested child titles are not pane reuse while launch ownership is active —
+  // except native OC| (#8478), which is provider identity, not a nested CLI.
   const titleReclaimsReusedPane =
     priorIdentity !== null &&
     explicitTitleAgent !== null &&
     explicitTitleAgent !== priorIdentity &&
     titleClaimsIdentity &&
-    !activeLaunchAgent &&
+    (!activeLaunchAgent || nativeOpenCodeTitle) &&
     (args.hasObservedAgentSignal || hasCompletedHook || nativeOpenCodeTitle)
-  // Why: OpenCode's native `OC |` frame is provider identity at startup (before hooks), not a nested child.
-  const openCodeStartupTitle =
-    nativeOpenCodeTitle &&
-    launchAgent !== null &&
-    launchAgent !== 'opencode' &&
-    !args.hasObservedAgentSignal
   // Why: native OpenCode titles lack a provider generation and cannot displace durable ownership.
   const titleAgent =
     processProvesShell ||
     sleepingSessionAgent ||
     (nativeOpenCodeTitle && idleFocusedIdentity !== null)
       ? null
-      : openCodeStartupTitle
+      : openCodeNativeReclaim || titleReclaimsReusedPane
         ? explicitTitleAgent
-        : titleReclaimsReusedPane
-          ? explicitTitleAgent
-          : priorIdentity
-            ? null
-            : explicitTitleAgent
+        : priorIdentity
+          ? null
+          : explicitTitleAgent
 
   // Identity-first precedence (see useTabAgent JSDoc): live hook > process > title > completed > sleeping > launch > sibling.
   return (

src/renderer/src/lib/use-tab-agent-nested-identity.test.ts

@@ -155,4 +155,55 @@ describe('resolveTabAgentFromSignals — nested child identity (#13341)', () =>
       })
     ).toBe('codex')
   })
+
+  // Why (#8478): native OC| reclaim must stay OpenCode after observation and under launch.
+  it('keeps OpenCode OC| reclaim after process observation under a non-OpenCode launch', () => {
+    expect(
+      resolveTabAgentFromSignals({
+        hasObservedAgentSignal: false,
+        isRemote: false,
+        title: 'OC | Greeting',
+        hookAgent: null,
+        processAgent: null,
+        launchAgent: 'claude'
+      })
+    ).toBe('opencode')
+    expect(
+      resolveTabAgentFromSignals({
+        hasObservedAgentSignal: true,
+        isRemote: false,
+        title: 'OC | Greeting',
+        hookAgent: null,
+        processAgent: 'claude',
+        launchAgent: 'claude'
+      })
+    ).toBe('opencode')
+  })
+
+  it('still fences nested Codex title under Claude launch (not OC|)', () => {
+    expect(
+      resolveTabAgentFromSignals({
+        hasObservedAgentSignal: true,
+        isRemote: false,
+        title: '✦ Codex',
+        hookAgent: null,
+        processAgent: 'codex',
+        launchAgent: 'claude'
+      })
+    ).toBe('claude')
+  })
+
+  it('clears OpenCode reclaim on shell return so launch can exit', () => {
+    expect(
+      resolveTabAgentFromSignals({
+        hasObservedAgentSignal: true,
+        isRemote: false,
+        title: 'zsh',
+        hookAgent: null,
+        processAgent: null,
+        processShellForeground: true,
+        launchAgent: 'claude'
+      })
+    ).toBeNull()
+  })
 })

src/renderer/src/lib/use-tab-agent-opencode-native-title.test.ts

@@ -241,18 +241,17 @@ describe('OpenCode native title tab identity', () => {
         launchAgent: 'claude'
       })
     ).toBe('claude')
-    // Why (#13341): nested process under active launch is not stronger than parent ownership.
+    // Why (#8478): native OC| reclaim is durable — process observation must not undo OpenCode.
     expect(
       resolveTabAgentFromSignals({
-        hasObservedAgentSignal: false,
+        hasObservedAgentSignal: true,
         isRemote: false,
         title: 'OC | Greeting',
         hookAgent: null,
         processAgent: 'codex',
-        sleepingSessionAgent: 'claude',
         launchAgent: 'claude'
       })
-    ).toBe('claude')
+    ).toBe('opencode')
 
     for (const title of [
       'OpenCode ready',