diff --git a/mobile/src/session/__mocks__/mobile-prompt-controller.ts b/mobile/src/session/__mocks__/mobile-prompt-controller.ts
index 20fb46add65..87f21239cac 100644
--- a/mobile/src/session/__mocks__/mobile-prompt-controller.ts
+++ b/mobile/src/session/__mocks__/mobile-prompt-controller.ts
@@ -83,7 +83,7 @@ vi.mock('../../components/ActionSheetModal', () => ({ ActionSheetModal: 'ActionS
 vi.mock('../../components/MobileMarkdown', () => ({ MobileMarkdown: 'Markdown' }))
 export const visible = { value: true }
 const session = { messages: [], folded: [], status: 'ready', transcriptLoading: false }
-const structured = {
+const structuredSession = {
   session,
   isWorking: false,
   turnId: null,
@@ -102,6 +102,7 @@ const structured = {
   setStructuredOption: vi.fn(),
   invokeStructuredOption: vi.fn()
 }
+const sessionCommands = { commands: undefined, refresh: vi.fn() }
 vi.mock('../use-mobile-session-view-mode', () => ({
   useMobileSessionViewMode: () => ({
     isTabChatView: () => visible.value,
@@ -111,7 +112,7 @@ vi.mock('../use-mobile-session-view-mode', () => ({
   })
 }))
 vi.mock('../use-mobile-native-chat-session-lane', () => ({
-  useMobileNativeChatSessionLane: () => ({ session, structuredSession: structured })
+  useMobileNativeChatSessionLane: () => ({ session, structuredSession, sessionCommands })
 }))
 vi.mock('../native-chat/composer/use-mobile-native-chat-drafts', () => ({
   useMobileNativeChatDrafts: () => ({
diff --git a/mobile/src/session/mobile-native-chat-controller-contract.ts b/mobile/src/session/mobile-native-chat-controller-contract.ts
index 4bbcc47e646..ad4d117397d 100644
--- a/mobile/src/session/mobile-native-chat-controller-contract.ts
+++ b/mobile/src/session/mobile-native-chat-controller-contract.ts
@@ -22,6 +22,7 @@ import type { MobileNativeChatPendingMessage } from './native-chat/mobile-native
 import type { useMobileNativeChatSession } from './use-mobile-native-chat-session'
 import type { MobileNativeChatSessionOptionPickersProps } from './MobileNativeChatSessionOptionPickers'
 import type { MobileNativeChatVisualSource } from './mobile-native-chat-visual-read'
+import type { useMobileStructuredSessionCommands } from './use-mobile-structured-session-commands'
 
 export type MobileNativeChatController = {
   sessionViewReady: boolean
@@ -93,5 +94,6 @@ export type MobileNativeChatController = {
   // Read parked TUI launch text to clear one line per Ctrl+U before pasting images.
   readSeededLaunchDraft: () => string | null
   nativeChatSessionOptions: MobileNativeChatSessionOptionPickersProps | null
+  nativeChatSessionCommands: ReturnType<typeof useMobileStructuredSessionCommands>
   nativeChatAcceptsImages: boolean
 }
diff --git a/mobile/src/session/mobile-structured-agent-session-contract.ts b/mobile/src/session/mobile-structured-agent-session-contract.ts
index 005723bcc44..236e48420bc 100644
--- a/mobile/src/session/mobile-structured-agent-session-contract.ts
+++ b/mobile/src/session/mobile-structured-agent-session-contract.ts
@@ -1,3 +1,4 @@
+import type { AgentSessionSlashCommand } from '../../../src/shared/agent-session-wire'
 import type { RpcClient } from '../transport/rpc-client'
 import type { StructuredAgentSessionHostSupport } from './mobile-structured-agent-session-host-support'
 import type { MobileNativeChatSendOutcome } from './native-chat/mobile-native-chat-send'
@@ -56,6 +57,8 @@ export type MobileStructuredAgentSessionArgs = {
   /** Capability facts from the shared runtime status probe; null follows the legacy wire. */
   hostSupport: StructuredAgentSessionHostSupport | null
   agent: string | null
+  /** What the session reported for its `/` menu; undefined until read or on an older host. */
+  sessionCommands?: readonly AgentSessionSlashCommand[]
   appendComposerText?: (text: string) => boolean
   onSendError: MobileNativeChatSendErrorReporter
   // Accepted queued actions retire the route’s failure banner.
diff --git a/mobile/src/session/mobile-structured-composer-command.test.ts b/mobile/src/session/mobile-structured-composer-command.test.ts
index bf41efc55c6..76fffa44af6 100644
--- a/mobile/src/session/mobile-structured-composer-command.test.ts
+++ b/mobile/src/session/mobile-structured-composer-command.test.ts
@@ -108,6 +108,19 @@ describe('mobile structured conversation commands', () => {
       expect(input.onError).toHaveBeenCalled()
     }
   )
+  it('leaves a session-reported command such as OMP /fast to an ordinary send', async () => {
+    const { input, sendRequest } = setup()
+    input.text = '/fast'
+    input.controller.agent = 'omp'
+    await dispatchMobileStructuredCommand(input)
+    expect(input.onError).toHaveBeenCalledWith(
+      expect.stringContaining('/fast is not available'),
+      undefined
+    )
+    input.controller.sessionCommands = [{ name: 'fast', kind: 'command' }]
+    expect(await dispatchMobileStructuredCommand(input)).toBeNull()
+    expect(sendRequest).not.toHaveBeenCalled()
+  })
   it('/clear is a plain command on every host: no withdrawal fields, nothing persisted', async () => {
     // The host carries cards to replacement sessions; client restoration would duplicate them.
     const { input, sendRequest } = setup()
diff --git a/mobile/src/session/mobile-structured-composer-command.ts b/mobile/src/session/mobile-structured-composer-command.ts
index ead086c5045..c90d091dcb9 100644
--- a/mobile/src/session/mobile-structured-composer-command.ts
+++ b/mobile/src/session/mobile-structured-composer-command.ts
@@ -44,7 +44,13 @@ export async function dispatchMobileStructuredCommand(input: {
   if (input.pending.current) {
     return 'rejected'
   }
-  if (!isStructuredAgentSessionComposerCommand(input.text, input.controller.agent)) {
+  if (
+    !isStructuredAgentSessionComposerCommand(
+      input.text,
+      input.controller.agent,
+      input.controller.sessionCommands
+    )
+  ) {
     return null
   }
   if (input.hasAttachments) {
diff --git a/mobile/src/session/native-chat/composer/use-mobile-native-chat-structured-composer.ts b/mobile/src/session/native-chat/composer/use-mobile-native-chat-structured-composer.ts
index 89b71d40c80..a538f8106ac 100644
--- a/mobile/src/session/native-chat/composer/use-mobile-native-chat-structured-composer.ts
+++ b/mobile/src/session/native-chat/composer/use-mobile-native-chat-structured-composer.ts
@@ -1,31 +1,22 @@
 import { useMemo } from 'react'
 import type { AgentSessionConversationCommand } from '../../../../../src/shared/agent-session/agent-session-conversation-command'
-import type { RpcClient } from '../../../transport/rpc-client'
 import type { MobileNativeChatStructuredComposer } from './MobileNativeChatComposer'
 import type { MobileNativeChatFileAttachments } from './use-mobile-native-chat-file-attachments'
-import { useMobileStructuredSessionCommands } from '../../use-mobile-structured-session-commands'
+import type { useMobileStructuredSessionCommands } from '../../use-mobile-structured-session-commands'
 
 const NO_COMMANDS: readonly AgentSessionConversationCommand[] = []
 
 export function useMobileNativeChatStructuredComposer(args: {
-  client: RpcClient | null
-  hostId: string | null
-  sessionId: string | null
   structured: boolean
-  connected: boolean
+  sessionCommands: ReturnType<typeof useMobileStructuredSessionCommands>
   /** The host keeps files a phone uploads; an older one refuses the upload. */
   acceptsFiles: boolean
   conversationCommands: readonly AgentSessionConversationCommand[] | undefined
   files: MobileNativeChatFileAttachments
 }): MobileNativeChatStructuredComposer | null {
-  const { client, hostId, sessionId, structured, connected, acceptsFiles, files } = args
+  const { structured, acceptsFiles, files } = args
   const conversationCommands = args.conversationCommands ?? NO_COMMANDS
-  const { commands, refresh } = useMobileStructuredSessionCommands({
-    client,
-    hostId,
-    sessionId,
-    enabled: structured && connected
-  })
+  const { commands, refresh } = args.sessionCommands
   const { files: pendingFiles, attachFiles, removeFiles } = files
   // Memoize commands separately so attachment changes cannot rebuild the menu catalog.
   const catalog = useMemo(
diff --git a/mobile/src/session/use-mobile-native-chat-controller.test.ts b/mobile/src/session/use-mobile-native-chat-controller.test.ts
index 5473ebc672f..2d5ea171644 100644
--- a/mobile/src/session/use-mobile-native-chat-controller.test.ts
+++ b/mobile/src/session/use-mobile-native-chat-controller.test.ts
@@ -81,6 +81,9 @@ vi.mock('./use-mobile-session-view-mode', () => ({
     toggleTabChatView: vi.fn()
   })
 }))
+vi.mock('./use-mobile-structured-session-commands', () => ({
+  useMobileStructuredSessionCommands: () => ({ commands: undefined, refresh: vi.fn() })
+}))
 vi.mock('./use-mobile-native-chat-session', () => ({
   useMobileNativeChatSession: () => sessionState
 }))
diff --git a/mobile/src/session/use-mobile-native-chat-controller.ts b/mobile/src/session/use-mobile-native-chat-controller.ts
index 158ec1a0e6b..8a1af933a95 100644
--- a/mobile/src/session/use-mobile-native-chat-controller.ts
+++ b/mobile/src/session/use-mobile-native-chat-controller.ts
@@ -54,7 +54,6 @@ export function useMobileNativeChatController(args: {
     onSendResolved
   } = args
   const {
-    activeChatAgent,
     activeChatAgentConfirmed,
     activeChatAgentRef,
     activeChatResolution,
@@ -75,22 +74,20 @@ export function useMobileNativeChatController(args: {
 
   // Fixed hook order mounts the lane before drafts; defer Edit’s append through a ref and delete nothing until copying succeeds.
   const appendComposerTextRef = useRef<(text: string) => boolean>(() => false)
-  const { structuredSession: structuredNativeChat, session: nativeChatSession } =
-    useMobileNativeChatSessionLane({
-      client,
-      structured: activeChatStructured,
-      agent: activeChatAgent,
-      resolvedAgent: activeChatResolution?.agent ?? null,
-      transcriptPath: activeChatResolution?.transcriptPath ?? null,
-      sessionId: activeChatSessionId,
-      sourceIdentity,
-      enabled: showNativeChat,
-      connState,
-      hostSupport: agentSessionHostSupport,
-      appendComposerTextRef,
-      onSendError,
-      onActionResolved: onSendResolved
-    })
+  const nativeChatLane = useMobileNativeChatSessionLane({
+    client,
+    hostId,
+    structured: activeChatStructured,
+    resolution: activeChatResolution,
+    sourceIdentity,
+    enabled: showNativeChat,
+    connState,
+    hostSupport: agentSessionHostSupport,
+    appendComposerTextRef,
+    onSendError,
+    onActionResolved: onSendResolved
+  })
+  const { structuredSession: structuredNativeChat, session: nativeChatSession } = nativeChatLane
   const {
     composerText: chatComposerText,
     setComposerText: setChatComposerText,
@@ -207,6 +204,7 @@ export function useMobileNativeChatController(args: {
 
   const structuredNativeChatSend = useMobileStructuredNativeChatSendBridge({
     agent: activeChatResolution?.agent,
+    sessionCommands: nativeChatLane.sessionCommands.commands,
     sendStructured: structuredNativeChat.sendWithOutcome,
     captureSendOrigin,
     clearDraftForSend,
@@ -317,6 +315,7 @@ export function useMobileNativeChatController(args: {
       : handleNativeChatSendWithOutcome,
     readSeededLaunchDraft,
     nativeChatSessionOptions,
+    nativeChatSessionCommands: nativeChatLane.sessionCommands,
     nativeChatAcceptsImages: !activeChatStructured || structuredNativeChat.acceptsImages
   }
 }
diff --git a/mobile/src/session/use-mobile-native-chat-session-lane.ts b/mobile/src/session/use-mobile-native-chat-session-lane.ts
index f3b320d4dcf..b1fb1138f2f 100644
--- a/mobile/src/session/use-mobile-native-chat-session-lane.ts
+++ b/mobile/src/session/use-mobile-native-chat-session-lane.ts
@@ -4,16 +4,16 @@ import type { ConnectionState } from '../transport/types'
 import type { StructuredAgentSessionHostSupport } from './mobile-structured-agent-session-host-support'
 import { useMobileNativeChatSession } from './use-mobile-native-chat-session'
 import { useMobileStructuredAgentSession } from './use-mobile-structured-agent-session'
+import { useMobileStructuredSessionCommands } from './use-mobile-structured-session-commands'
+import type { MobileNativeChatResolution } from './native-chat/mobile-native-chat-eligibility'
 import type { MobileNativeChatSendErrorReporter } from './native-chat/use-mobile-native-chat-send-error'
 
 // Run both hooks in fixed order and starve the inactive lane’s identity so flips preserve cached transcripts.
 export function useMobileNativeChatSessionLane({
   client,
+  hostId,
   structured,
-  agent,
-  resolvedAgent,
-  transcriptPath,
-  sessionId,
+  resolution,
   sourceIdentity,
   hostSupport,
   appendComposerTextRef,
@@ -23,11 +23,9 @@ export function useMobileNativeChatSessionLane({
   onActionResolved
 }: {
   client: RpcClient | null
+  hostId: string
   structured: boolean
-  agent: string | null
-  resolvedAgent: string | null
-  transcriptPath: string | null
-  sessionId: string | null
+  resolution: MobileNativeChatResolution | null
   sourceIdentity: Parameters<typeof useMobileNativeChatSession>[0]['sourceIdentity']
   hostSupport: StructuredAgentSessionHostSupport | null
   // Defer Edit through the composer ref because drafts mount after this lane.
@@ -39,17 +37,27 @@ export function useMobileNativeChatSessionLane({
 }): {
   structuredSession: ReturnType<typeof useMobileStructuredAgentSession>
   session: ReturnType<typeof useMobileNativeChatSession>
+  sessionCommands: ReturnType<typeof useMobileStructuredSessionCommands>
 } {
   const appendComposerText = useCallback(
     (text: string) => appendComposerTextRef.current(text),
     [appendComposerTextRef]
   )
+  const agent = resolution?.agent ?? null
+  const sessionId = resolution?.sessionId ?? null
+  // One read serves both send-side ownership and the composer's `/` menu.
+  const sessionCommands = useMobileStructuredSessionCommands({
+    client,
+    hostId,
+    sessionId: structured ? sessionId : null,
+    enabled: connState === 'connected'
+  })
   const bridgeSession = useMobileNativeChatSession({
     client,
     sourceIdentity,
-    agent: structured ? null : resolvedAgent,
+    agent: structured ? null : agent,
     sessionId: structured ? null : sessionId,
-    transcriptPath: structured ? null : transcriptPath
+    transcriptPath: structured ? null : (resolution?.transcriptPath ?? null)
   })
   const structuredSession = useMobileStructuredAgentSession({
     client,
@@ -62,11 +70,13 @@ export function useMobileNativeChatSessionLane({
     // reacquire the provider without clearing the cached transcript.
     connected: connState === 'connected',
     agent: structured ? agent : null,
+    sessionCommands: sessionCommands.commands,
     onSendError,
     ...(onActionResolved ? { onActionResolved } : {})
   })
   return {
     structuredSession,
-    session: structured ? structuredSession.session : bridgeSession
+    session: structured ? structuredSession.session : bridgeSession,
+    sessionCommands
   }
 }
diff --git a/mobile/src/session/use-mobile-session-attachments.ts b/mobile/src/session/use-mobile-session-attachments.ts
index 2e5bb595243..4f9814cdc84 100644
--- a/mobile/src/session/use-mobile-session-attachments.ts
+++ b/mobile/src/session/use-mobile-session-attachments.ts
@@ -109,11 +109,8 @@ export function useMobileSessionAttachments(scope: MobileSessionAccessorySelecti
       onError: triggerError
     })
   const nativeChatStructuredComposer = useMobileNativeChatStructuredComposer({
-    client,
-    hostId,
-    sessionId: nativeChatSessionId,
     structured: structuredNativeChat,
-    connected: connState === 'connected',
+    sessionCommands: nativeChatController.nativeChatSessionCommands,
     acceptsFiles: agentSessionHostSupport?.phoneAttachments === true,
     conversationCommands:
       nativeChatController.nativeChatSessionOptions?.controller.conversationCommands,
diff --git a/mobile/src/session/use-mobile-structured-agent-session.ts b/mobile/src/session/use-mobile-structured-agent-session.ts
index adc55580d06..791915909bb 100644
--- a/mobile/src/session/use-mobile-structured-agent-session.ts
+++ b/mobile/src/session/use-mobile-structured-agent-session.ts
@@ -191,6 +191,7 @@ export function useMobileStructuredAgentSession(
     hold: sends.hold,
     commandPending: commandPendingRef,
     controller: sendController,
+    sessionCommands: args.sessionCommands,
     onSendError,
     sendOptions: hostSupport?.sendOptions === true ? options.sendSelection : undefined
   })
diff --git a/mobile/src/session/use-mobile-structured-native-chat-send-bridge.ts b/mobile/src/session/use-mobile-structured-native-chat-send-bridge.ts
index 6609fdfa9af..834f997c2a3 100644
--- a/mobile/src/session/use-mobile-structured-native-chat-send-bridge.ts
+++ b/mobile/src/session/use-mobile-structured-native-chat-send-bridge.ts
@@ -1,5 +1,6 @@
 import { useCallback } from 'react'
 import type { StructuredAgentId } from '../../../src/shared/agent-session-provider-handle'
+import type { AgentSessionSlashCommand } from '../../../src/shared/agent-session-wire'
 import { isStructuredAgentSessionComposerCommand } from '../../../src/shared/structured-agent-session-composer'
 import type { MobileNativeChatSendOutcome } from './native-chat/mobile-native-chat-send'
 import type { MobileNativeChatSendOrigin } from './native-chat/mobile-native-chat-pending-echo'
@@ -7,6 +8,7 @@ import type { StructuredMobileSendAttachment } from './use-mobile-structured-sen
 
 export function useMobileStructuredNativeChatSendBridge(args: {
   agent: StructuredAgentId | undefined
+  sessionCommands?: readonly AgentSessionSlashCommand[]
   sendStructured: (
     text: string,
     images?: string[],
@@ -32,7 +34,8 @@ export function useMobileStructuredNativeChatSendBridge(args: {
     clearDraftForSend,
     onSendError,
     restoreRejectedDraft,
-    sendStructured
+    sendStructured,
+    sessionCommands
   } = args
   const sendWithOutcome = useCallback(
     async (
@@ -46,7 +49,7 @@ export function useMobileStructuredNativeChatSendBridge(args: {
         onSendError('Message not sent (disconnected)')
         return 'rejected'
       }
-      const isHostCommand = isStructuredAgentSessionComposerCommand(text, agent)
+      const isHostCommand = isStructuredAgentSessionComposerCommand(text, agent, sessionCommands)
       clearDraftForSend(origin, text)
       const outcome =
         attachments !== undefined
@@ -62,7 +65,15 @@ export function useMobileStructuredNativeChatSendBridge(args: {
       }
       return outcome
     },
-    [agent, captureSendOrigin, clearDraftForSend, onSendError, restoreRejectedDraft, sendStructured]
+    [
+      agent,
+      captureSendOrigin,
+      clearDraftForSend,
+      onSendError,
+      restoreRejectedDraft,
+      sendStructured,
+      sessionCommands
+    ]
   )
   const send = useCallback(
     async (
diff --git a/mobile/src/session/use-mobile-structured-send-with-outcome.ts b/mobile/src/session/use-mobile-structured-send-with-outcome.ts
index 01f3df3663e..d6fe941dbeb 100644
--- a/mobile/src/session/use-mobile-structured-send-with-outcome.ts
+++ b/mobile/src/session/use-mobile-structured-send-with-outcome.ts
@@ -8,6 +8,7 @@ import {
   type StructuredAgentSessionAttachment
 } from '../../../src/shared/structured-agent-session-send-mutation'
 import type { StructuredAgentSessionComposerOptions } from '../../../src/shared/structured-agent-session-composer'
+import type { AgentSessionSlashCommand } from '../../../src/shared/agent-session-wire'
 import type { StructuredAgentSessionState } from '../../../src/shared/structured-agent-session-reducer'
 import type { RpcClient } from '../transport/rpc-client'
 import type { MobileNativeChatSendOutcome } from './native-chat/mobile-native-chat-send'
@@ -53,6 +54,7 @@ export function useMobileStructuredSendWithOutcome(args: {
     StructuredAgentSessionComposerOptions,
     'snapshot' | 'setOption' | 'invokeAction' | 'conversationCommands'
   >
+  sessionCommands?: readonly AgentSessionSlashCommand[]
   onSendError: MobileNativeChatSendErrorReporter
   // Older hosts accept neither per-chat model nor effort.
   sendOptions?: () => Readonly<Record<string, string>> | undefined
@@ -74,6 +76,7 @@ export function useMobileStructuredSendWithOutcome(args: {
     onSendError,
     queueCapable,
     sendOptions,
+    sessionCommands,
     sessionId,
     stateRef,
     stopping
@@ -107,7 +110,7 @@ export function useMobileStructuredSendWithOutcome(args: {
         sessionId,
         fence: currentFence,
         pending: commandPending,
-        controller: { agent: agent ?? undefined, ...controller },
+        controller: { agent: agent ?? undefined, ...controller, sessionCommands },
         busy: () =>
           actionableStructuredApproval(stateRef.current) ||
           actionableStructuredQuestion(stateRef.current)
@@ -180,6 +183,7 @@ export function useMobileStructuredSendWithOutcome(args: {
       onSendError,
       queueCapable,
       sendOptions,
+      sessionCommands,
       sessionId,
       stateRef,
       stopping
diff --git a/src/renderer/src/components/native-chat/use-native-chat-structured-composer-send.ts b/src/renderer/src/components/native-chat/use-native-chat-structured-composer-send.ts
index 8e7ad36f2f3..a3b315023df 100644
--- a/src/renderer/src/components/native-chat/use-native-chat-structured-composer-send.ts
+++ b/src/renderer/src/components/native-chat/use-native-chat-structured-composer-send.ts
@@ -47,7 +47,7 @@ function isNativeChatStructuredHostCommand(
   transport: NativeChatStructuredComposerTransport
 ): boolean {
   return (
-    isStructuredAgentSessionComposerCommand(text, agent) ||
+    isStructuredAgentSessionComposerCommand(text, agent, transport.sessionCommands) ||
     (transport.threadGoal !== undefined && isStructuredAgentSessionGoalCommand(text))
   )
 }
diff --git a/src/renderer/src/components/native-chat/use-native-chat-structured-composer-transport.ts b/src/renderer/src/components/native-chat/use-native-chat-structured-composer-transport.ts
index 7d31bf3aee6..aad904a609e 100644
--- a/src/renderer/src/components/native-chat/use-native-chat-structured-composer-transport.ts
+++ b/src/renderer/src/components/native-chat/use-native-chat-structured-composer-transport.ts
@@ -86,6 +86,7 @@ export function useNativeChatStructuredComposerTransport(args: {
             return true
           },
           setOption: controller.setStructuredOption,
+          sessionCommands: controller.sessionCommands,
           conversationCommands: controller.conversationCommands,
           runConversationCommand: controller.runConversationCommand,
           ...(setThreadGoalObjective ? { setThreadGoalObjective } : {})
diff --git a/src/shared/structured-agent-session-composer.test.ts b/src/shared/structured-agent-session-composer.test.ts
index d809a59bc1d..d3585d6bbf4 100644
--- a/src/shared/structured-agent-session-composer.test.ts
+++ b/src/shared/structured-agent-session-composer.test.ts
@@ -264,6 +264,25 @@ describe('agent-implemented commands pass through to the agent', () => {
     expect(setThreadGoalObjective).not.toHaveBeenCalled()
   })
 
+  // OMP's ACP catalog advertises only commands it handles itself, e.g. /fast.
+  it('passes a session-reported command on to the session that advertised it', async () => {
+    const sessionCommands = [
+      { name: 'fast', kind: 'command' },
+      { name: 'compact', kind: 'command' }
+    ] as const
+    expect(isStructuredAgentSessionComposerCommand('/fast', 'omp')).toBe(true)
+    expect(isStructuredAgentSessionComposerCommand('/fast', 'omp', sessionCommands)).toBe(false)
+    expect(
+      await dispatchStructuredAgentSessionComposerCommand('/fast status', {
+        ...controller,
+        agent: 'omp',
+        sessionCommands
+      })
+    ).toEqual(PASSED_THROUGH)
+    // Orca still runs its own commands even when the session reports them.
+    expect(isStructuredAgentSessionComposerCommand('/compact', 'omp', sessionCommands)).toBe(true)
+  })
+
   it('keeps refusing a Codex command the model cannot carry out', async () => {
     expect(isStructuredAgentSessionComposerCommand('/permissions', 'codex')).toBe(true)
     expect(
diff --git a/src/shared/structured-agent-session-composer.ts b/src/shared/structured-agent-session-composer.ts
index b0d4b6eb841..98bfa427cf4 100644
--- a/src/shared/structured-agent-session-composer.ts
+++ b/src/shared/structured-agent-session-composer.ts
@@ -37,6 +37,8 @@ export type StructuredAgentSessionComposerOptions = {
   snapshot: readonly SessionOptionDescriptor[]
   invokeAction: (id: string) => Promise<boolean>
   setOption: (id: string, value: SessionOptionValue) => Promise<boolean>
+  /** What the running session reported for its `/` menu; undefined until read or on an older host. */
+  sessionCommands?: readonly AgentSessionSlashCommand[]
   conversationCommands?: readonly AgentSessionConversationCommand[]
   runConversationCommand?: (
     command: AgentSessionConversationCommand
@@ -106,12 +108,19 @@ export function structuredSessionSlashCommands(
   ]
 }
 
-/** Claim hidden TUI-only commands too, preventing literal prose delivery; leave agent-handled commands unclaimed for passthrough. */
-function structuredRecognizedCommands(agent: AgentType): readonly SlashCommandSuggestion[] {
+/** Claim hidden TUI-only commands too, preventing literal prose delivery; leave agent-handled
+ *  and session-reported commands unclaimed for passthrough. */
+function structuredRecognizedCommands(
+  agent: AgentType,
+  reported: readonly AgentSessionSlashCommand[] | undefined
+): readonly SlashCommandSuggestion[] {
+  const sessionHandled = new Set(
+    reported?.filter((entry) => entry.kind === 'command').map((entry) => entry.name)
+  )
   return [
     ...STRUCTURED_AGENT_SESSION_SLASH_COMMANDS,
     ...CONVERSATION_COMMANDS,
-    ...getHostClaimedNativeChatCommands(agent)
+    ...getHostClaimedNativeChatCommands(agent).filter((entry) => !sessionHandled.has(entry.name))
   ]
 }
 
@@ -120,11 +129,13 @@ function structuredRecognizedCommands(agent: AgentType): readonly SlashCommandSu
  *  would be silently dropped, whereas a pass-through command is a real send. */
 export function isStructuredAgentSessionComposerCommand(
   text: string,
-  agent: AgentType = 'codex'
+  agent: AgentType = 'codex',
+  reported?: readonly AgentSessionSlashCommand[]
 ): boolean {
   const command = commandParts(text)
   return Boolean(
-    command && structuredRecognizedCommands(agent).some((entry) => entry.name === command.name)
+    command &&
+    structuredRecognizedCommands(agent, reported).some((entry) => entry.name === command.name)
   )
 }
 
@@ -189,7 +200,10 @@ export async function dispatchStructuredAgentSessionComposerCommand(
       error: null
     }
   }
-  if (!command || !isStructuredAgentSessionComposerCommand(text, controller.agent)) {
+  if (
+    !command ||
+    !isStructuredAgentSessionComposerCommand(text, controller.agent, controller.sessionCommands)
+  ) {
     return { handled: false, accepted: false, error: null }
   }
   if (command.name === 'clear' || command.name === 'compact') {