diff --git a/src/cli/handlers/orchestration/dispatch-handlers.ts b/src/cli/handlers/orchestration/dispatch-handlers.ts
index afe79ab8e2f..5162ca6e291 100644
--- a/src/cli/handlers/orchestration/dispatch-handlers.ts
+++ b/src/cli/handlers/orchestration/dispatch-handlers.ts
@@ -5,7 +5,7 @@ import { RuntimeClientError } from '../../runtime-client'
 import { orchestrationMigrationData } from '../../../shared/orchestration-rpc-contract'
 import { callOrchestrationMutation } from './mutation-request'
 import { isDevCliInvocation } from './runtime-compatibility'
-import { resolveCoordinatorTerminalHandle } from './terminal-identity'
+import { injectedSessionAddress, resolveCoordinatorTerminalHandle } from './terminal-identity'
 
 export const ORCHESTRATION_DISPATCH_HANDLER: Record<string, CommandHandler> = {
   'orchestration dispatch': async ({ flags, client, cwd, json }) => {
@@ -42,9 +42,12 @@ export const ORCHESTRATION_DISPATCH_HANDLER: Record<string, CommandHandler> = {
 export const ORCHESTRATION_DISPATCH_INSPECTION_HANDLERS: Record<string, CommandHandler> = {
   'orchestration dispatch-show': async ({ flags, client, cwd, json }) => {
     const showPreamble = flags.has('preamble') ? true : undefined
-    // Why: a preview must embed the same real coordinator handle as an actual dispatch.
+    // Why: a preview must embed the same real coordinator handle as an actual dispatch. Its --from
+    // only fills preview text and names no caller, so it passes through unfenced.
     const from = showPreamble
-      ? await resolveCoordinatorTerminalHandle(flags, cwd, client)
+      ? (getOptionalStringFlag(flags, 'from') ??
+        injectedSessionAddress() ??
+        (await resolveCoordinatorTerminalHandle(flags, cwd, client)))
       : undefined
     const result = await client.call<{
       dispatch: { id: string; task_id: string; status: string } | null
diff --git a/src/cli/handlers/orchestration/terminal-identity.ts b/src/cli/handlers/orchestration/terminal-identity.ts
index f9d72d76e3a..732fb13a77f 100644
--- a/src/cli/handlers/orchestration/terminal-identity.ts
+++ b/src/cli/handlers/orchestration/terminal-identity.ts
@@ -173,7 +173,7 @@ function getClientErrorMessage(err: unknown): string | undefined {
  * identity this process carries; a caller flag may restate that same session but never name
  * another, and a conflicting one is refused here, before any request is sent.
  */
-export function resolveInjectedSessionCaller(
+function resolveInjectedSessionCaller(
   flags: Map<string, string | boolean>,
   flagName: 'from' | 'terminal'
 ): string | undefined {
@@ -195,17 +195,25 @@ export function resolveInjectedSessionCaller(
 
 /** The session's own spellings, plus the handle a structured worker session was minted. */
 function namesInjectedSession(value: string, sessionId: string): boolean {
-  if (normalizeOrchestrationActor(value)?.id === sessionId) {
-    return true
+  return normalizeOrchestrationActor(value)?.id === sessionId || value === injectedSessionAddress()
+}
+
+/**
+ * The address the host gives this session: a structured worker keeps the handle it was minted, any
+ * other session is `session:<id>`. Only for text that must match what the host writes.
+ */
+export function injectedSessionAddress(): string | undefined {
+  const sessionId = readInjectedAgentSessionId()
+  if (!sessionId) {
+    return undefined
   }
   const ownHandle = process.env.ORCA_TERMINAL_HANDLE
-  return isStructuredWorkerHandle(ownHandle) && value === ownHandle
+  return isStructuredWorkerHandle(ownHandle) ? ownHandle : `session:${sessionId}`
 }
 
 /** How check output names its caller: the handle, or the session's address. */
 export function orchestrationCallerLabel(handle: string | undefined): string {
-  const sessionId = handle === undefined ? readInjectedAgentSessionId() : undefined
-  return handle ?? (sessionId ? `session:${sessionId}` : 'unknown')
+  return handle ?? injectedSessionAddress() ?? 'unknown'
 }
 
 export async function resolveCoordinatorTerminalHandle(
diff --git a/src/cli/handlers/orchestration/worker-list-run-scope.ts b/src/cli/handlers/orchestration/worker-list-run-scope.ts
index 83bfcd5b9e0..13037616153 100644
--- a/src/cli/handlers/orchestration/worker-list-run-scope.ts
+++ b/src/cli/handlers/orchestration/worker-list-run-scope.ts
@@ -1,9 +1,6 @@
 import { getOptionalStringFlag } from '../../flags'
 import type { RuntimeClient } from '../../runtime-client'
-import {
-  resolveInjectedSessionCaller,
-  resolveOrchestrationTerminalHandle
-} from './terminal-identity'
+import { resolveOrchestrationTerminalHandle } from './terminal-identity'
 
 /** Which Run `worker-list` enumerated, and why. Additive: old readers ignore it. */
 export type WorkerListRunScope = { run?: string; source: 'flag' | 'bound' | 'all' }
@@ -23,9 +20,6 @@ export async function resolveWorkerListRunScope(
   if (explicit) {
     return { run: explicit, source: 'flag' }
   }
-  // Outside the catch: a --terminal naming someone other than this session is refused, never
-  // widened into an unscoped listing.
-  resolveInjectedSessionCaller(flags, 'terminal')
   try {
     const terminal = await resolveOrchestrationTerminalHandle(flags, cwd, client, 'terminal')
     const current = await client.call<{ run: { id: string } | null }>('orchestration.runCurrent', {
diff --git a/src/cli/orchestration-session-caller-cli.test.ts b/src/cli/orchestration-session-caller-cli.test.ts
new file mode 100644
index 00000000000..93a76645a30
--- /dev/null
+++ b/src/cli/orchestration-session-caller-cli.test.ts
@@ -0,0 +1,476 @@
+/**
+ * A command that runs inside a structured agent session is that session: the injected
+ * `ORCA_AGENT_SESSION_ID` names the caller, and nothing resolves or guesses a terminal for it.
+ *
+ * One rule for every verb that names a caller: a caller flag may restate the session, but a flag
+ * naming anyone else is refused before any request — never silently dropped, never allowed to win.
+ * The #21097 accident was a chat that named a sibling's terminal and consumed that sibling's mail.
+ *
+ * The session env here is the hardest case, a chat in terminal view: it also carries its pane's
+ * `ORCA_TERMINAL_HANDLE` and `ORCA_PANE_KEY`, and the implicit-terminal guess has a sibling to find.
+ */
+
+import { afterEach, beforeEach, describe, expect, it, vi } from 'vitest'
+
+const callMock = vi.hoisted(() => vi.fn())
+const getTerminalHandleMock = vi.hoisted(() => vi.fn())
+
+vi.mock('./format', () => ({ printResult: vi.fn() }))
+vi.mock('./selectors', () => ({ getTerminalHandle: getTerminalHandleMock }))
+
+import { ORCHESTRATION_HANDLERS } from './handlers/orchestration'
+import { createOrchestrationCompatibilityEnvelope } from './runtime/orchestration-compatibility-envelope'
+
+const SESSION = 'f7a1c0de-1111-4222-8333-444455556666'
+const IDENTITY_ENV = [
+  'ORCA_AGENT_SESSION_ID',
+  'ORCA_TERMINAL_HANDLE',
+  'ORCA_PANE_KEY',
+  'ORCA_STRUCTURED_SESSION'
+] as const
+const originalEnv = Object.fromEntries(IDENTITY_ENV.map((name) => [name, process.env[name]]))
+
+/** Enough of every receipt shape that each handler finishes after its RPC. */
+const RESULT = {
+  result: {
+    run: { id: 'run_1', objective: 'o', consumer_generation: 1 },
+    runs: [],
+    nextCursor: null,
+    messages: [],
+    count: 0,
+    message: { id: 'msg_1' },
+    lifecycle: { action: 'completed' },
+    dispatch: { id: 'dispatch_1', task_id: 'task_1', status: 'dispatched' },
+    gate: { id: 'gate_1', task_id: 'task_1', status: 'pending', resolution: 'r' },
+    gates: [],
+    task: { id: 'task_1', status: 'pending' },
+    tasks: [],
+    answer: 'yes',
+    messageId: 'msg_1',
+    threadId: 'thread_1',
+    timedOut: false,
+    state: 'ready',
+    runId: 'run_1',
+    taskId: 'task_1',
+    dispatchId: 'dispatch_1',
+    effects: [],
+    residualResources: [],
+    workers: [],
+    counts: {}
+  }
+}
+
+type Verb = {
+  command: string
+  flags: Record<string, string | true>
+  /** The flag that names the caller, when the verb has one. */
+  callerFlag?: 'from' | 'terminal'
+  method: string
+  callerParam: 'from' | 'terminal' | 'callerTerminalHandle'
+}
+
+/** Every verb whose request names its caller: the host's caller-param map, from the CLI side.
+ *  `dispatch-show` is not one: its --from only fills preview text, so it is pinned on its own. */
+const CALLER_VERBS: Verb[] = [
+  {
+    command: 'run-create',
+    flags: { objective: 'o' },
+    callerFlag: 'from',
+    method: 'runCreate',
+    callerParam: 'from'
+  },
+  {
+    command: 'run-use',
+    flags: { id: 'run_1' },
+    callerFlag: 'from',
+    method: 'runUse',
+    callerParam: 'from'
+  },
+  {
+    command: 'run-current',
+    flags: {},
+    callerFlag: 'from',
+    method: 'runCurrent',
+    callerParam: 'from'
+  },
+  { command: 'check', flags: {}, callerFlag: 'terminal', method: 'check', callerParam: 'terminal' },
+  {
+    command: 'send',
+    flags: { to: 'term_worker', subject: 's', body: 'b' },
+    callerFlag: 'from',
+    method: 'send',
+    callerParam: 'from'
+  },
+  {
+    command: 'reply',
+    flags: { id: 'msg_1', body: 'b' },
+    callerFlag: 'from',
+    method: 'reply',
+    callerParam: 'from'
+  },
+  {
+    command: 'ask',
+    flags: { to: 'term_worker', question: 'q' },
+    callerFlag: 'from',
+    method: 'ask',
+    callerParam: 'from'
+  },
+  {
+    command: 'dispatch',
+    flags: { task: 'task_1', to: 'term_worker' },
+    callerFlag: 'from',
+    method: 'dispatch',
+    callerParam: 'from'
+  },
+  {
+    command: 'gate-create',
+    flags: { task: 'task_1', question: 'q' },
+    callerFlag: 'from',
+    method: 'gateCreate',
+    callerParam: 'from'
+  },
+  {
+    command: 'gate-resolve',
+    flags: { id: 'gate_1', resolution: 'r' },
+    callerFlag: 'from',
+    method: 'gateResolve',
+    callerParam: 'from'
+  },
+  { command: 'gate-list', flags: {}, callerFlag: 'from', method: 'gateList', callerParam: 'from' },
+  {
+    command: 'task-create',
+    flags: { spec: 's' },
+    callerFlag: 'from',
+    method: 'taskCreate',
+    callerParam: 'callerTerminalHandle'
+  },
+  {
+    command: 'task-list',
+    flags: {},
+    callerFlag: 'from',
+    method: 'taskList',
+    callerParam: 'callerTerminalHandle'
+  },
+  {
+    command: 'task-update',
+    flags: { id: 'task_1', status: 'completed' },
+    callerFlag: 'from',
+    method: 'taskUpdate',
+    callerParam: 'callerTerminalHandle'
+  },
+  {
+    command: 'worker-start',
+    flags: { spec: 's' },
+    callerFlag: 'from',
+    method: 'workerStart',
+    callerParam: 'from'
+  },
+  // No caller flag: its spec takes none. It asks runCurrent for the caller's Run.
+  { command: 'worker-list', flags: {}, method: 'runCurrent', callerParam: 'from' }
+]
+
+function flagMap(flags: Record<string, string | true>): Map<string, string | boolean> {
+  return new Map(Object.entries(flags))
+}
+
+async function invoke(
+  command: string,
+  flags: Map<string, string | boolean>,
+  json = true
+): Promise<void> {
+  const handler = ORCHESTRATION_HANDLERS[`orchestration ${command}`]
+  if (!handler) {
+    throw new Error(`no handler for ${command}`)
+  }
+  await handler({
+    flags,
+    // oxlint-disable-next-line typescript/consistent-type-assertions -- SAFETY: these handlers read only `call`; RuntimeClient is a class, so a structural double cannot satisfy it without the cast.
+    client: { call: callMock } as never,
+    cwd: '/tmp/repo',
+    json
+  })
+}
+
+function isParams(value: unknown): value is Record<string, unknown> {
+  return typeof value === 'object' && value !== null && !Array.isArray(value)
+}
+
+function callsTo(method: string): Record<string, unknown>[] {
+  return callMock.mock.calls
+    .filter(([name]) => name === `orchestration.${method}`)
+    .map(([, params]) => (isParams(params) ? params : {}))
+}
+
+function setEnv(env: Partial<Record<(typeof IDENTITY_ENV)[number], string>>): void {
+  for (const name of IDENTITY_ENV) {
+    const value = env[name]
+    if (value === undefined) {
+      delete process.env[name]
+    } else {
+      process.env[name] = value
+    }
+  }
+}
+
+/** A chat in terminal view: its id, plus the pane identity that view inherits. */
+function asSessionInTerminalView(): void {
+  setEnv({
+    ORCA_AGENT_SESSION_ID: SESSION,
+    ORCA_TERMINAL_HANDLE: 'term_view_pane',
+    ORCA_PANE_KEY: 'tab_view:11111111-1111-4111-8111-111111111111'
+  })
+}
+
+beforeEach(() => {
+  callMock.mockReset().mockResolvedValue(RESULT)
+  getTerminalHandleMock.mockReset().mockResolvedValue('term_sibling')
+  vi.spyOn(console, 'log').mockImplementation(() => {})
+  vi.spyOn(console, 'error').mockImplementation(() => {})
+})
+
+afterEach(() => {
+  vi.restoreAllMocks()
+  setEnv(originalEnv)
+  process.exitCode = undefined
+})
+
+describe.each(CALLER_VERBS)('orchestration $command run as an agent session', (verb) => {
+  beforeEach(asSessionInTerminalView)
+
+  it('acts as the session: no terminal is resolved, guessed or sent', async () => {
+    await invoke(verb.command, flagMap(verb.flags))
+
+    const [params] = callsTo(verb.method)
+    expect(params, 'the verb reached its method').toBeDefined()
+    expect(params?.[verb.callerParam]).toBeUndefined()
+    // A terminal view's pane is not the session's identity.
+    expect(params?.terminalPaneKey).toBeUndefined()
+    expect(params?.senderPaneKey).toBeUndefined()
+    expect(getTerminalHandleMock).not.toHaveBeenCalled()
+    expect(callMock.mock.calls.map(([name]) => name)).not.toEqual(
+      expect.arrayContaining([expect.stringMatching(/^terminal\./)])
+    )
+  })
+
+  it.runIf(verb.callerFlag !== undefined)(
+    'refuses a caller flag naming another actor, before any request',
+    async () => {
+      const flags = flagMap({ ...verb.flags, [verb.callerFlag ?? 'from']: 'term_sibling' })
+
+      await expect(invoke(verb.command, flags)).rejects.toMatchObject({
+        code: 'consumer_fenced',
+        message: expect.stringContaining(`agent session ${SESSION}`)
+      })
+      expect(callMock).not.toHaveBeenCalled()
+      expect(getTerminalHandleMock).not.toHaveBeenCalled()
+    }
+  )
+
+  it.runIf(verb.callerFlag !== undefined)(
+    "refuses its own terminal view's pane handle too: the session, not the pane, is the caller",
+    async () => {
+      const flags = flagMap({ ...verb.flags, [verb.callerFlag ?? 'from']: 'term_view_pane' })
+
+      await expect(invoke(verb.command, flags)).rejects.toMatchObject({ code: 'consumer_fenced' })
+      expect(callMock).not.toHaveBeenCalled()
+    }
+  )
+
+  it.runIf(verb.callerFlag !== undefined).each([`session:${SESSION}`, SESSION])(
+    'accepts a caller flag that restates the session (%s)',
+    async (restated) => {
+      await invoke(verb.command, flagMap({ ...verb.flags, [verb.callerFlag ?? 'from']: restated }))
+
+      const [params] = callsTo(verb.method)
+      expect(params, 'the verb reached its method').toBeDefined()
+      expect(params?.[verb.callerParam]).toBeUndefined()
+    }
+  )
+})
+
+describe('the identity a session presents', () => {
+  it("lets a structured worker restate its own minted handle, and nobody else's", async () => {
+    setEnv({ ORCA_AGENT_SESSION_ID: SESSION, ORCA_TERMINAL_HANDLE: 'structworker_self' })
+
+    await invoke('send', flagMap({ from: 'structworker_self', to: 'run:run_1', subject: 's' }))
+    expect(callsTo('send')[0]?.from).toBeUndefined()
+
+    callMock.mockClear()
+    await expect(
+      invoke('send', flagMap({ from: 'structworker_other', to: 'run:run_1', subject: 's' }))
+    ).rejects.toMatchObject({ code: 'consumer_fenced' })
+    expect(callMock).not.toHaveBeenCalled()
+  })
+
+  it("sends a structured worker's lifecycle report as the session, not refused as identity-less", async () => {
+    setEnv({ ORCA_AGENT_SESSION_ID: SESSION })
+
+    await invoke(
+      'send',
+      flagMap({ to: 'run:run_1', subject: 'done', type: 'worker_done', outcome: 'succeeded' })
+    )
+
+    expect(callsTo('send')[0]).toMatchObject({ type: 'worker_done' })
+    expect(callsTo('send')[0]?.from).toBeUndefined()
+  })
+
+  it('never treats a session that has an id as identity-less, even beside the old marker', async () => {
+    setEnv({ ORCA_AGENT_SESSION_ID: SESSION, ORCA_STRUCTURED_SESSION: '1' })
+
+    await invoke('check', flagMap({}))
+
+    expect(callsTo('check')).toHaveLength(1)
+    expect(getTerminalHandleMock).not.toHaveBeenCalled()
+  })
+
+  it('keeps the identity-less refusal, without --from advice, for a child that has no id', async () => {
+    setEnv({ ORCA_STRUCTURED_SESSION: '1' })
+
+    await expect(invoke('reply', flagMap({ id: 'msg_1', body: 'b' }))).rejects.toMatchObject({
+      code: 'no_active_sender_terminal',
+      message: expect.not.stringContaining('Pass --from')
+    })
+    expect(getTerminalHandleMock).not.toHaveBeenCalled()
+    expect(callMock).not.toHaveBeenCalled()
+  })
+
+  it('leaves a terminal agent exactly as it was: its own handle is the caller', async () => {
+    setEnv({ ORCA_TERMINAL_HANDLE: 'term_pty', ORCA_PANE_KEY: 'tab_pty:1:2' })
+    callMock.mockImplementation(async (name: string) =>
+      name === 'terminal.resolveIdentity' ? { result: { identity: { live: true } } } : RESULT
+    )
+
+    await invoke('run-create', flagMap({ objective: 'o' }))
+    await invoke('check', flagMap({}))
+
+    expect(callsTo('runCreate')[0]?.from).toBe('term_pty')
+    expect(callsTo('check')[0]).toMatchObject({
+      terminal: 'term_pty',
+      terminalPaneKey: 'tab_pty:1:2'
+    })
+  })
+
+  it('previews a dispatch with the coordinator address the real dispatch would write', async () => {
+    const preview = async (flags: Record<string, string | true>) => {
+      callMock.mockClear()
+      await invoke('dispatch-show', flagMap({ task: 'task_1', preamble: true, ...flags }))
+      return callsTo('dispatchShow')[0]?.from
+    }
+    asSessionInTerminalView()
+    expect(await preview({})).toBe(`session:${SESSION}`)
+    // Not a caller flag: it names the text to preview, so it is never fenced.
+    expect(await preview({ from: 'term_sibling' })).toBe('term_sibling')
+    setEnv({ ORCA_AGENT_SESSION_ID: SESSION, ORCA_TERMINAL_HANDLE: 'structworker_self' })
+    expect(await preview({})).toBe('structworker_self')
+    expect(getTerminalHandleMock).not.toHaveBeenCalled()
+  })
+
+  it('resumes a timed-out ask as the session, without naming a terminal', async () => {
+    asSessionInTerminalView()
+    callMock.mockResolvedValue({ result: { ...RESULT.result, answer: null, timedOut: true } })
+    const errors = vi.mocked(console.error)
+
+    await invoke('ask', flagMap({ to: 'term_worker', question: 'q' }), false)
+
+    const advice = errors.mock.calls.map(([line]) => String(line)).join('\n')
+    expect(advice).toContain('--resume msg_1')
+    expect(advice).not.toContain('--from')
+  })
+})
+
+describe('the orchestration envelope', () => {
+  it('carries the injected id beside whatever terminal evidence the process also has', () => {
+    const envelope = createOrchestrationCompatibilityEnvelope({
+      ORCA_AGENT_SESSION_ID: ` ${SESSION} `,
+      ORCA_TERMINAL_HANDLE: 'term_view_pane'
+    })
+
+    expect(envelope.orchestrationCompatibilityEvidence).toEqual({
+      terminalHandle: 'term_view_pane',
+      agentSessionId: SESSION
+    })
+  })
+
+  it('claims no session without an injected id', () => {
+    expect(
+      createOrchestrationCompatibilityEnvelope({ ORCA_AGENT_SESSION_ID: '  ' })
+        .orchestrationCompatibilityEvidence
+    ).toBeUndefined()
+  })
+
+  it('keeps a WSL stamp beside the id, so the host can refuse the cross-host claim', () => {
+    const envelope = createOrchestrationCompatibilityEnvelope({
+      ORCA_AGENT_SESSION_ID: SESSION,
+      ORCA_ORCHESTRATION_COMPATIBILITY_HOST_KIND: 'wsl',
+      ORCA_ORCHESTRATION_COMPATIBILITY_HOST_ID: 'local',
+      ORCA_ORCHESTRATION_COMPATIBILITY_HOST_INCARNATION: 'Ubuntu'
+    })
+
+    expect(envelope.orchestrationCompatibilityEvidence).toEqual({
+      agentSessionId: SESSION,
+      host: { kind: 'wsl', hostId: 'local', distro: 'Ubuntu' }
+    })
+  })
+})
+
+describe('every orchestration verb, enumerated', () => {
+  /** Enough flags for any verb to get past its own validation to identity resolution. */
+  const EVERY_REQUIRED_FLAG = {
+    objective: 'o',
+    id: 'id_1',
+    task: 'task_1',
+    spec: 's',
+    question: 'q',
+    resolution: 'r',
+    subject: 's',
+    body: 'b',
+    to: 'term_worker',
+    status: 'completed',
+    preamble: true,
+    request: 'req_1'
+  } as const
+
+  /** Runs every verb once; returns the ones that guessed an implicit terminal. */
+  async function verbsThatGuess(): Promise<string[]> {
+    const guessed: string[] = []
+    for (const command of Object.keys(ORCHESTRATION_HANDLERS)) {
+      const verb = command.replace('orchestration ', '')
+      getTerminalHandleMock.mockClear()
+      callMock.mockClear()
+      await invoke(verb, flagMap(EVERY_REQUIRED_FLAG)).catch(() => undefined)
+      if (getTerminalHandleMock.mock.calls.length > 0) {
+        guessed.push(verb)
+      }
+    }
+    return guessed.sort()
+  }
+
+  it('guesses a terminal for no verb when the session id is present', async () => {
+    // Positive control first: with no identity at all the same harness sees the guess, so an empty
+    // result below is about the id, not a harness that cannot observe a guess.
+    setEnv({})
+    const population = await verbsThatGuess()
+    expect(population).toEqual([
+      'ask',
+      'check',
+      'dispatch',
+      'dispatch-show',
+      'gate-create',
+      'gate-list',
+      'gate-resolve',
+      'reply',
+      'run-create',
+      'run-current',
+      'run-use',
+      'send',
+      'task-create',
+      'task-list',
+      'task-update',
+      'worker-list',
+      'worker-start'
+    ])
+
+    asSessionInTerminalView()
+    expect(await verbsThatGuess()).toEqual([])
+  })
+})
diff --git a/src/main/runtime/rpc/orchestration-session-caller.test.ts b/src/main/runtime/rpc/orchestration-session-caller.test.ts
index c91ad0ff169..d96e214d442 100644
--- a/src/main/runtime/rpc/orchestration-session-caller.test.ts
+++ b/src/main/runtime/rpc/orchestration-session-caller.test.ts
@@ -43,6 +43,7 @@ const PARTY_NAMING_FIELDS = ['to', 'from', 'terminal', 'callerTerminalHandle'] a
 const NAMES_NO_RESOLVED_PARTY: Readonly<Record<string, string>> = {
   'orchestration.run from': 'retired; refused before any handler',
   'orchestration.runShow from': 'reads a Run by id; `from` is unused',
+  'orchestration.dispatchShow from': '`from` only fills the preview preamble text',
   'orchestration.workerStart terminal': 'adopts an existing PTY pane, which a session never has',
   'orchestration.federationAttachStart terminal': 'names the remote worker terminal',
   'orchestration.workerTerminalUserInput terminal': 'names the worker terminal'
@@ -58,7 +59,6 @@ const MINIMAL_PARAMS: Readonly<Record<string, Record<string, unknown>>> = {
   'orchestration.reply': { id: 'msg_missing', body: 'b' },
   'orchestration.ask': { question: 'q', to: 'term_worker' },
   'orchestration.dispatch': { task: 'task_missing', to: 'term_worker' },
-  'orchestration.dispatchShow': { task: 'task_missing', preamble: true },
   'orchestration.gateCreate': { task: 'task_missing', question: 'q' },
   'orchestration.gateResolve': { id: 'gate_missing', resolution: 'r' },
   'orchestration.gateList': {},
diff --git a/src/main/runtime/rpc/orchestration-session-caller.ts b/src/main/runtime/rpc/orchestration-session-caller.ts
index deeeb397ca3..e4bd09f2619 100644
--- a/src/main/runtime/rpc/orchestration-session-caller.ts
+++ b/src/main/runtime/rpc/orchestration-session-caller.ts
@@ -50,8 +50,6 @@ export const ORCHESTRATION_CALLER_PARAM: Readonly<Record<string, CallerParam>> =
   'orchestration.reply': 'from',
   'orchestration.ask': 'from',
   'orchestration.dispatch': 'from',
-  // The preview names its caller as the coordinator, exactly as the dispatch it previews does.
-  'orchestration.dispatchShow': 'from',
   'orchestration.gateCreate': 'from',
   'orchestration.gateResolve': 'from',
   'orchestration.gateList': 'from',
diff --git a/src/shared/structured-worker-handle.ts b/src/shared/structured-worker-handle.ts
index e36df813570..c9fd3927c02 100644
--- a/src/shared/structured-worker-handle.ts
+++ b/src/shared/structured-worker-handle.ts
@@ -2,6 +2,6 @@
 // renderer-driven leaves map, so a main-minted `term_` leaf evaporates on the next window reload.
 export const STRUCTURED_WORKER_HANDLE_PREFIX = 'structworker_'
 
-export function isStructuredWorkerHandle(handle: string | null | undefined): boolean {
+export function isStructuredWorkerHandle(handle: string | null | undefined): handle is string {
   return typeof handle === 'string' && handle.startsWith(STRUCTURED_WORKER_HANDLE_PREFIX)
 }