diff --git a/src/main/daemon/daemon-pty-adapter.test.ts b/src/main/daemon/daemon-pty-adapter.test.ts
index ace70f1f7..862540075 100644
--- a/src/main/daemon/daemon-pty-adapter.test.ts
+++ b/src/main/daemon/daemon-pty-adapter.test.ts
@@ -14,6 +14,8 @@ const { getMacDaemonSystemResolverHealthMock } = vi.hoisted(() => ({
   getMacDaemonSystemResolverHealthMock: vi.fn(async () => 'unknown')
 }))
 
+const itOnPosix = process.platform === 'win32' ? it.skip : it
+
 vi.mock('./daemon-health', async (importOriginal) => {
   const actual = await importOriginal<typeof DaemonHealthModule>()
   return {
@@ -123,6 +125,37 @@ describe('DaemonPtyAdapter (IPtyProvider)', () => {
       const result = await adapter.spawn({ cols: 80, rows: 24, worktreeId: 'wt-1' })
       expect(result.id).toContain('wt-1')
     })
+
+    itOnPosix('keeps plain Codex startup on the short daemon shell-ready timeout', async () => {
+      await adapter.spawn({
+        cols: 80,
+        rows: 24,
+        command: 'codex',
+        env: { SHELL: '/bin/zsh' }
+      })
+
+      await waitFor(() => vi.mocked(lastSubprocess.write).mock.calls.length > 0)
+      expect(lastSubprocess.write).toHaveBeenCalledWith('codex\n')
+    })
+
+    itOnPosix('waits for shell-ready for delivery-hinted Codex startup', async () => {
+      await adapter.spawn({
+        cols: 80,
+        rows: 24,
+        command: "codex 'linked issue context'",
+        startupCommandDelivery: 'shell-ready',
+        env: { SHELL: '/bin/zsh' }
+      })
+
+      await new Promise((resolve) => setTimeout(resolve, 350))
+      expect(lastSubprocess.write).not.toHaveBeenCalled()
+
+      lastSubprocess._simulateData('\x1b]777;orca-shell-ready\x07')
+      lastSubprocess._simulateData('\r\nuser@host $ ')
+
+      await waitFor(() => vi.mocked(lastSubprocess.write).mock.calls.length > 0)
+      expect(lastSubprocess.write).toHaveBeenCalledWith("codex 'linked issue context'\n")
+    })
   })
 
   describe('write', () => {
diff --git a/src/main/daemon/daemon-pty-adapter.ts b/src/main/daemon/daemon-pty-adapter.ts
index 61140d91e..59fee26d3 100644
--- a/src/main/daemon/daemon-pty-adapter.ts
+++ b/src/main/daemon/daemon-pty-adapter.ts
@@ -22,6 +22,7 @@ import {
 import type { IPtyProvider, PtySpawnOptions, PtySpawnResult } from '../providers/types'
 import { isShellProcess } from '../../shared/agent-detection'
 import { recognizeAgentProcessFromCommandLine } from '../../shared/agent-process-recognition'
+import { shouldUseShellReadyStartupDelivery } from '../../shared/codex-startup-delivery'
 
 export type DaemonPtyAdapterOptions = {
   socketPath: string
@@ -136,8 +137,16 @@ export class DaemonPtyAdapter implements IPtyProvider {
     await this.ensureConnected()
 
     const shellReadySupported = opts.command ? supportsPtyStartupBarrier(opts.env ?? {}) : false
+    const isCodexStartupCommand =
+      recognizeAgentProcessFromCommandLine(opts.command)?.agent === 'codex'
+    const shouldWaitForShellReady =
+      isCodexStartupCommand &&
+      shouldUseShellReadyStartupDelivery({
+        command: opts.command,
+        startupCommandDelivery: opts.startupCommandDelivery
+      })
     const shellReadyTimeoutMs =
-      shellReadySupported && recognizeAgentProcessFromCommandLine(opts.command)?.agent === 'codex'
+      shellReadySupported && isCodexStartupCommand && !shouldWaitForShellReady
         ? CODEX_SHELL_READY_TIMEOUT_MS
         : undefined
 
@@ -149,6 +158,7 @@ export class DaemonPtyAdapter implements IPtyProvider {
       env: opts.env,
       envToDelete: opts.envToDelete,
       command: opts.command,
+      startupCommandDelivery: opts.startupCommandDelivery,
       // Why: without this, the daemon always spawns cmd.exe (COMSPEC) or
       // PowerShell as a fallback — regardless of which shell the renderer
       // asked for in the "+" menu or persisted as the default. Forwarding
diff --git a/src/main/daemon/daemon-server.ts b/src/main/daemon/daemon-server.ts
index f7b93ea3c..af1afebb5 100644
--- a/src/main/daemon/daemon-server.ts
+++ b/src/main/daemon/daemon-server.ts
@@ -274,6 +274,7 @@ export class DaemonServer {
           env: p.env,
           envToDelete: p.envToDelete,
           command: p.command,
+          startupCommandDelivery: p.startupCommandDelivery,
           shellOverride: p.shellOverride,
           terminalWindowsWslDistro: p.terminalWindowsWslDistro,
           terminalWindowsPowerShellImplementation: p.terminalWindowsPowerShellImplementation,
diff --git a/src/main/daemon/pty-subprocess.test.ts b/src/main/daemon/pty-subprocess.test.ts
index 93522066d..ada8a4f32 100644
--- a/src/main/daemon/pty-subprocess.test.ts
+++ b/src/main/daemon/pty-subprocess.test.ts
@@ -951,6 +951,85 @@ describe('createPtySubprocess', () => {
     expect(lastCall[2].env.ORCA_SHELL_READY_MARKER).toBe('0')
   })
 
+  it('keeps plain Codex startup commands on the no-marker wrapper', () => {
+    const proc = mockPtyProcess()
+    spawnMock.mockReturnValue(proc)
+    const platform = Object.getOwnPropertyDescriptor(process, 'platform')
+    Object.defineProperty(process, 'platform', { value: 'linux' })
+
+    try {
+      createPtySubprocess({
+        sessionId: 'test',
+        cols: 80,
+        rows: 24,
+        command: 'codex',
+        env: { SHELL: '/bin/zsh' }
+      })
+    } finally {
+      if (platform) {
+        Object.defineProperty(process, 'platform', platform)
+      }
+    }
+
+    const lastCall = spawnMock.mock.calls.at(-1)!
+    expect(lastCall[1]).toEqual(['-l'])
+    expect(lastCall[2].env.ZDOTDIR).toMatch(ZSH_SHELL_READY_DIR)
+    expect(lastCall[2].env.ORCA_SHELL_READY_MARKER).toBe('0')
+  })
+
+  it('uses shell-ready wrapper for delivery-hinted Codex startup commands', () => {
+    const proc = mockPtyProcess()
+    spawnMock.mockReturnValue(proc)
+    const platform = Object.getOwnPropertyDescriptor(process, 'platform')
+    Object.defineProperty(process, 'platform', { value: 'linux' })
+
+    try {
+      createPtySubprocess({
+        sessionId: 'test',
+        cols: 80,
+        rows: 24,
+        command: "codex 'linked issue context'",
+        startupCommandDelivery: 'shell-ready',
+        env: { SHELL: '/bin/zsh' }
+      })
+    } finally {
+      if (platform) {
+        Object.defineProperty(process, 'platform', platform)
+      }
+    }
+
+    const lastCall = spawnMock.mock.calls.at(-1)!
+    expect(lastCall[1]).toEqual(['-l'])
+    expect(lastCall[2].env.ZDOTDIR).toMatch(ZSH_SHELL_READY_DIR)
+    expect(lastCall[2].env.ORCA_SHELL_READY_MARKER).toBe('1')
+  })
+
+  it('uses shell-ready wrapper for Codex native prefill flags', () => {
+    const proc = mockPtyProcess()
+    spawnMock.mockReturnValue(proc)
+    const platform = Object.getOwnPropertyDescriptor(process, 'platform')
+    Object.defineProperty(process, 'platform', { value: 'linux' })
+
+    try {
+      createPtySubprocess({
+        sessionId: 'test',
+        cols: 80,
+        rows: 24,
+        command: "codex --prefill 'linked issue context'",
+        env: { SHELL: '/bin/zsh' }
+      })
+    } finally {
+      if (platform) {
+        Object.defineProperty(process, 'platform', platform)
+      }
+    }
+
+    const lastCall = spawnMock.mock.calls.at(-1)!
+    expect(lastCall[1]).toEqual(['-l'])
+    expect(lastCall[2].env.ZDOTDIR).toMatch(ZSH_SHELL_READY_DIR)
+    expect(lastCall[2].env.ORCA_SHELL_READY_MARKER).toBe('1')
+  })
+
   it('deletes requested env keys after merging daemon process env', () => {
     const proc = mockPtyProcess()
     spawnMock.mockReturnValue(proc)
diff --git a/src/main/daemon/pty-subprocess.ts b/src/main/daemon/pty-subprocess.ts
index 291757945..60f046a8e 100644
--- a/src/main/daemon/pty-subprocess.ts
+++ b/src/main/daemon/pty-subprocess.ts
@@ -33,6 +33,10 @@ import {
   recognizeAgentProcess,
   recognizeAgentProcessFromCommandLine
 } from '../../shared/agent-process-recognition'
+import {
+  shouldUseShellReadyStartupDelivery,
+  type StartupCommandDelivery
+} from '../../shared/codex-startup-delivery'
 import { isShellProcess } from '../../shared/shell-process-detection'
 import { parsePtySessionId } from './pty-session-id'
 import { getAgentForegroundContextPaths } from '../providers/agent-foreground-context-paths'
@@ -51,6 +55,7 @@ export type PtySubprocessOptions = {
   env?: Record<string, string>
   envToDelete?: string[]
   command?: string
+  startupCommandDelivery?: StartupCommandDelivery
   /** Explicit shell executable path/basename the renderer asked for.
    *  Overrides env.COMSPEC / env.SHELL resolution inside the daemon so a user
    *  who picks "New WSL terminal" from the "+" menu actually gets WSL. */
@@ -504,9 +509,15 @@ export function createPtySubprocess(opts: PtySubprocessOptions): SubprocessHandl
     // wrapper need shell-ready code after user startup files run.
     let shellLaunch: ReturnType<typeof getShellReadyLaunchConfig> | null = null
     if (opts.command && isCodexStartupCommand) {
-      // Why: Codex needs the env-restoring wrapper, but waiting for a shell
-      // marker delays the first useful TUI frame.
-      shellLaunch = getAttributionShellLaunchConfig(shellPath)
+      const shouldWaitForShellReady = shouldUseShellReadyStartupDelivery({
+        command: opts.command,
+        startupCommandDelivery: opts.startupCommandDelivery
+      })
+      // Why: payload-bearing Codex startup text can be dropped by rc-file noise;
+      // plain Codex stays markerless to preserve the startup-speed path.
+      shellLaunch = shouldWaitForShellReady
+        ? getShellReadyLaunchConfig(shellPath)
+        : getAttributionShellLaunchConfig(shellPath)
     } else if (opts.command) {
       shellLaunch = getShellReadyLaunchConfig(shellPath)
     } else {
diff --git a/src/main/daemon/terminal-host.ts b/src/main/daemon/terminal-host.ts
index dc96e72e8..2bb4473b4 100644
--- a/src/main/daemon/terminal-host.ts
+++ b/src/main/daemon/terminal-host.ts
@@ -1,6 +1,7 @@
 import { Session, type SubprocessHandle } from './session'
 import { normalizePtySize } from './daemon-pty-size'
 import { resolveProcessCwd } from '../providers/process-cwd'
+import type { StartupCommandDelivery } from '../../shared/codex-startup-delivery'
 import type {
   SessionInfo,
   TakePendingOutputResult,
@@ -19,6 +20,7 @@ export type CreateOrAttachOptions = {
   env?: Record<string, string>
   envToDelete?: string[]
   command?: string
+  startupCommandDelivery?: StartupCommandDelivery
   /** Explicit shell the renderer asked for (e.g. 'wsl.exe' for "New WSL
    *  terminal" from the "+" menu). Forwarded to the subprocess spawner so the
    *  daemon path honors per-tab shell selection the same way LocalPtyProvider
@@ -48,6 +50,7 @@ export type TerminalHostOptions = {
     env?: Record<string, string>
     envToDelete?: string[]
     command?: string
+    startupCommandDelivery?: StartupCommandDelivery
     shellOverride?: string
     terminalWindowsWslDistro?: string | null
     terminalWindowsPowerShellImplementation?: 'auto' | 'powershell.exe' | 'pwsh.exe'
@@ -113,6 +116,7 @@ export class TerminalHost {
       env: opts.env,
       envToDelete: opts.envToDelete,
       command: opts.command,
+      startupCommandDelivery: opts.startupCommandDelivery,
       shellOverride: opts.shellOverride,
       terminalWindowsWslDistro: opts.terminalWindowsWslDistro,
       terminalWindowsPowerShellImplementation: opts.terminalWindowsPowerShellImplementation
diff --git a/src/main/daemon/types.ts b/src/main/daemon/types.ts
index e0afca9ad..609b41849 100644
--- a/src/main/daemon/types.ts
+++ b/src/main/daemon/types.ts
@@ -1,11 +1,13 @@
 // ─── Protocol Version ────────────────────────────────────────────────
+import type { StartupCommandDelivery } from '../../shared/codex-startup-delivery'
+
 // Why: daemons can survive app updates. Bump for IPC wire-shape changes, or
 // when daemon-baked behavior cannot be delivered by on-disk wrapper refresh.
 // Why: bump when adding daemon wire behavior so same-version old daemons do
 // not silently accept the handshake and then reject new RPCs.
-export const PROTOCOL_VERSION = 15
+export const PROTOCOL_VERSION = 16
 export const PREVIOUS_DAEMON_PROTOCOL_VERSIONS = [
-  1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14
+  1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15
 ] as const
 
 // ─── Session State Machine ──────────────────────────────────────────
@@ -87,6 +89,7 @@ export type CreateOrAttachRequest = {
     env?: Record<string, string>
     envToDelete?: string[]
     command?: string
+    startupCommandDelivery?: StartupCommandDelivery
     /** Explicit Windows shell override selected by the user (e.g. 'wsl.exe').
      *  The daemon forwards this to its subprocess spawner so each tab honors
      *  the shell picked in the "+" menu or the persisted default-shell setting,
diff --git a/src/main/ipc/pty.test.ts b/src/main/ipc/pty.test.ts
index cd35b332c..9c875a1be 100644
--- a/src/main/ipc/pty.test.ts
+++ b/src/main/ipc/pty.test.ts
@@ -4826,6 +4826,72 @@ describe('registerPtyHandlers', () => {
     }
   )
 
+  posixOnlyIt('waits for shell-ready before writing delivery-hinted Codex startup', async () => {
+    vi.useFakeTimers()
+    const mockProc = createMockProc()
+    spawnMock.mockReturnValue(mockProc.proc)
+
+    try {
+      registerPtyHandlers(mainWindow as never)
+      await handlers.get('pty:spawn')!(null, {
+        cols: 80,
+        rows: 24,
+        cwd: '/tmp',
+        command: "codex 'linked issue context'",
+        startupCommandDelivery: 'shell-ready'
+      })
+
+      const [, , options] = spawnMock.mock.calls[0]!
+      expect(options.env.ORCA_SHELL_READY_MARKER).toBe('1')
+      expect(mockProc.proc.write).not.toHaveBeenCalled()
+
+      mockProc.emitData('last login: today\r\n')
+      vi.advanceTimersByTime(1499)
+      await Promise.resolve()
+      expect(mockProc.proc.write).not.toHaveBeenCalled()
+
+      mockProc.emitData('\x1b]777;orca-shell-ready\x07')
+      await Promise.resolve()
+      vi.advanceTimersByTime(49)
+      await Promise.resolve()
+      expect(mockProc.proc.write).not.toHaveBeenCalled()
+
+      vi.advanceTimersByTime(1)
+      await Promise.resolve()
+      expect(mockProc.proc.write).toHaveBeenCalledWith("codex 'linked issue context'\n")
+    } finally {
+      vi.useRealTimers()
+    }
+  })
+
+  posixOnlyIt('waits for shell-ready when Codex uses the native prefill flag', async () => {
+    vi.useFakeTimers()
+    const mockProc = createMockProc()
+    spawnMock.mockReturnValue(mockProc.proc)
+
+    try {
+      registerPtyHandlers(mainWindow as never)
+      await handlers.get('pty:spawn')!(null, {
+        cols: 80,
+        rows: 24,
+        cwd: '/tmp',
+        command: "codex --prefill 'linked issue context'"
+      })
+
+      const [, , options] = spawnMock.mock.calls[0]!
+      expect(options.env.ORCA_SHELL_READY_MARKER).toBe('1')
+      expect(mockProc.proc.write).not.toHaveBeenCalled()
+
+      mockProc.emitData('\x1b]777;orca-shell-ready\x07')
+      await Promise.resolve()
+      vi.runAllTimers()
+      await Promise.resolve()
+      expect(mockProc.proc.write).toHaveBeenCalledWith("codex --prefill 'linked issue context'\n")
+    } finally {
+      vi.useRealTimers()
+    }
+  })
+
   posixOnlyIt('keeps the conservative max wait for non-agent startup commands', async () => {
     vi.useFakeTimers()
     const mockProc = createMockProc()
diff --git a/src/main/ipc/pty.ts b/src/main/ipc/pty.ts
index 21afd28c2..9fadd52cc 100644
--- a/src/main/ipc/pty.ts
+++ b/src/main/ipc/pty.ts
@@ -23,6 +23,7 @@ import { detectPiAgentKindFromCommand, type PiAgentKind } from '../../shared/pi-
 import { isPwshAvailable } from '../pwsh'
 import { LocalPtyProvider } from '../providers/local-pty-provider'
 import type { IPtyProvider, PtySpawnOptions, PtySpawnResult } from '../providers/types'
+import type { StartupCommandDelivery } from '../../shared/codex-startup-delivery'
 import { SSH_SESSION_EXPIRED_ERROR, isSshPtyNotFoundError } from '../providers/ssh-pty-provider'
 import { parseAppSshPtyId, toAppSshPtyId, toRelaySshPtyId } from '../providers/ssh-pty-id'
 import { mintPtySessionId, isSafePtySessionId } from '../daemon/pty-session-id'
@@ -1750,6 +1751,9 @@ export function registerPtyHandlers(
       if (args.command !== undefined) {
         spawnOptions.command = args.command
       }
+      if (args.startupCommandDelivery !== undefined) {
+        spawnOptions.startupCommandDelivery = args.startupCommandDelivery
+      }
       if (args.worktreeId !== undefined) {
         spawnOptions.worktreeId = args.worktreeId
       }
@@ -2098,6 +2102,7 @@ export function registerPtyHandlers(
         env?: Record<string, string>
         envToDelete?: string[]
         command?: string
+        startupCommandDelivery?: StartupCommandDelivery
         connectionId?: string | null
         worktreeId?: string
         sessionId?: string
@@ -2348,6 +2353,9 @@ export function registerPtyHandlers(
       if (args.command !== undefined) {
         spawnOptions.command = args.command
       }
+      if (args.startupCommandDelivery !== undefined) {
+        spawnOptions.startupCommandDelivery = args.startupCommandDelivery
+      }
       if (args.worktreeId !== undefined) {
         spawnOptions.worktreeId = args.worktreeId
       }
diff --git a/src/main/ipc/worktree-remote.ts b/src/main/ipc/worktree-remote.ts
index 638f15f67..9a6f39dbe 100644
--- a/src/main/ipc/worktree-remote.ts
+++ b/src/main/ipc/worktree-remote.ts
@@ -245,6 +245,7 @@ async function spawnLocalStartupAndSetupTerminals(args: {
     const terminal = await runtime.createTerminal(`id:${worktree.id}`, {
       command: startup.command,
       env: startup.env,
+      startupCommandDelivery: startup.startupCommandDelivery,
       telemetry: startup.telemetry,
       activate: true
     })
diff --git a/src/main/providers/local-pty-provider.test.ts b/src/main/providers/local-pty-provider.test.ts
index 9beba9ace..e9187f341 100644
--- a/src/main/providers/local-pty-provider.test.ts
+++ b/src/main/providers/local-pty-provider.test.ts
@@ -191,6 +191,35 @@ describe('LocalPtyProvider', () => {
       expect(spawnCall[2].env.CUSTOM_VAR).toBe('custom-value')
     })
 
+    it('uses fallback shell readiness when startup-command shell spawn falls back', async () => {
+      vi.useFakeTimers()
+      try {
+        process.env.SHELL = '/usr/bin/fish'
+        spawnMock.mockImplementationOnce(() => {
+          throw new Error('fish failed')
+        })
+        spawnMock.mockReturnValue(mockProc)
+
+        await provider.spawn({ cols: 80, rows: 24, command: "printf 'linked issue context'" })
+
+        expect(spawnMock.mock.calls[0]?.[0]).toBe('/bin/zsh')
+        await Promise.resolve()
+        vi.advanceTimersByTime(50)
+        await Promise.resolve()
+        expect(mockProc.write).not.toHaveBeenCalled()
+
+        const dataCallback = mockProc.onData.mock.calls[0]?.[0] as (data: string) => void
+        dataCallback('\x1b]777;orca-shell-ready\x07user@host % ')
+        await Promise.resolve()
+        vi.advanceTimersByTime(50)
+        await Promise.resolve()
+
+        expect(mockProc.write).toHaveBeenCalledWith("printf 'linked issue context'\n")
+      } finally {
+        vi.useRealTimers()
+      }
+    })
+
     it('honors explicit terminal env overrides after deleting requested defaults', async () => {
       provider.configure({
         buildSpawnEnv: (_id, env) => {
diff --git a/src/main/providers/local-pty-provider.ts b/src/main/providers/local-pty-provider.ts
index 966bd2efd..0b7da3deb 100644
--- a/src/main/providers/local-pty-provider.ts
+++ b/src/main/providers/local-pty-provider.ts
@@ -42,6 +42,7 @@ import { WINDOWS_GIT_BASH_SHELL } from '../../shared/windows-terminal-shell'
 import { resolveAgentForegroundProcess } from './agent-foreground-process'
 import { getAgentForegroundContextPaths } from './agent-foreground-context-paths'
 import { recognizeAgentProcessFromCommandLine } from '../../shared/agent-process-recognition'
+import { shouldUseShellReadyStartupDelivery } from '../../shared/codex-startup-delivery'
 
 const PANE_IDENTITY_ENV_KEYS = ['ORCA_PANE_KEY', 'ORCA_TAB_ID', 'ORCA_WORKTREE_ID'] as const
 
@@ -476,10 +477,19 @@ export class LocalPtyProvider implements IPtyProvider {
         recognizeAgentProcessFromCommandLine(args.command)?.agent === 'codex'
       let shellLaunch: ReturnType<typeof getShellReadyLaunchConfig> | null = null
       if (args.command && isCodexStartupCommand) {
-        // Why: Codex needs the env-restoring wrapper, but waiting for a shell
-        // marker delays the first useful TUI frame.
-        getFallbackShellReadyConfig = (shell) => getAttributionShellLaunchConfig(shell)
-        shellLaunch = getAttributionShellLaunchConfig(shellPath)
+        const shouldWaitForShellReady = shouldUseShellReadyStartupDelivery({
+          command: args.command,
+          startupCommandDelivery: args.startupCommandDelivery
+        })
+        // Why: payload-bearing Codex startup text can be dropped by rc-file noise;
+        // plain Codex stays markerless to preserve the startup-speed path.
+        getFallbackShellReadyConfig = (shell) =>
+          shouldWaitForShellReady
+            ? getShellReadyLaunchConfig(shell)
+            : getAttributionShellLaunchConfig(shell)
+        shellLaunch = shouldWaitForShellReady
+          ? getShellReadyLaunchConfig(shellPath)
+          : getAttributionShellLaunchConfig(shellPath)
       } else if (args.command) {
         getFallbackShellReadyConfig = (shell) => getShellReadyLaunchConfig(shell)
         shellLaunch = getShellReadyLaunchConfig(shellPath)
@@ -534,6 +544,9 @@ export class LocalPtyProvider implements IPtyProvider {
         : undefined
     })
     shellPath = spawnResult.shellPath
+    if (args.command && getFallbackShellReadyConfig) {
+      shellReadyLaunch = getFallbackShellReadyConfig(shellPath)
+    }
 
     if (process.platform !== 'win32') {
       finalEnv.SHELL = shellPath
diff --git a/src/main/providers/local-pty-shell-ready.test.ts b/src/main/providers/local-pty-shell-ready.test.ts
index d029dba6b..629baf764 100644
--- a/src/main/providers/local-pty-shell-ready.test.ts
+++ b/src/main/providers/local-pty-shell-ready.test.ts
@@ -8,7 +8,11 @@ import { join, dirname } from 'path'
 import { mkdtempSync, readFileSync, rmSync, writeFileSync, mkdirSync } from 'fs'
 import type * as pty from 'node-pty'
 import type * as LocalPtyShellReadyModule from './local-pty-shell-ready'
-import { writeStartupCommandWhenShellReady } from './local-pty-shell-ready'
+import {
+  createShellReadyScanState,
+  scanForShellReady,
+  writeStartupCommandWhenShellReady
+} from './local-pty-shell-ready'
 
 const { getUserDataPathMock } = vi.hoisted(() => ({
   getUserDataPathMock: vi.fn<() => string>()
@@ -128,6 +132,21 @@ describe('writeStartupCommandWhenShellReady', () => {
   })
 })
 
+describe('scanForShellReady', () => {
+  it('flushes marker-like output when the full marker is not BEL-terminated', () => {
+    const state = createShellReadyScanState()
+
+    expect(scanForShellReady(state, 'before \x1b]777;orca-shell-readyx')).toEqual({
+      output: 'before \x1b]777;orca-shell-readyx',
+      matched: false
+    })
+    expect(scanForShellReady(state, ' after')).toEqual({
+      output: ' after',
+      matched: false
+    })
+  })
+})
+
 const describePosix = process.platform === 'win32' ? describe.skip : describe
 const hasBash = process.platform !== 'win32' && spawnSync('bash', ['--version']).status === 0
 const itWithBash = hasBash ? it : it.skip
diff --git a/src/main/providers/local-pty-shell-ready.ts b/src/main/providers/local-pty-shell-ready.ts
index 7872fcd84..1175ddaf4 100644
--- a/src/main/providers/local-pty-shell-ready.ts
+++ b/src/main/providers/local-pty-shell-ready.ts
@@ -74,7 +74,15 @@ export function scanForShellReady(
       state.matchPos = 0
       return { output: output + remaining, matched: true }
     } else {
-      state.heldBytes += ch
+      output += state.heldBytes
+      state.heldBytes = ''
+      state.matchPos = 0
+      if (ch === SHELL_READY_MARKER[0]) {
+        state.heldBytes = ch
+        state.matchPos = 1
+      } else {
+        output += ch
+      }
     }
   }
 
diff --git a/src/main/providers/ssh-pty-provider.ts b/src/main/providers/ssh-pty-provider.ts
index 8883b88a3..327bbb9d7 100644
--- a/src/main/providers/ssh-pty-provider.ts
+++ b/src/main/providers/ssh-pty-provider.ts
@@ -137,7 +137,10 @@ export class SshPtyProvider implements IPtyProvider {
       // relay does not execute `command` itself — the user types it into
       // the shell — but receiving it as a hint lets overlay resolution be
       // per-launch instead of always-Pi.
-      ...(opts.command ? { command: opts.command } : {})
+      ...(opts.command ? { command: opts.command } : {}),
+      ...(opts.startupCommandDelivery
+        ? { startupCommandDelivery: opts.startupCommandDelivery }
+        : {})
     })
     return {
       ...(result as PtySpawnResult),
diff --git a/src/main/providers/types.ts b/src/main/providers/types.ts
index 85c5017ad..ceef32852 100644
--- a/src/main/providers/types.ts
+++ b/src/main/providers/types.ts
@@ -18,6 +18,7 @@ import type {
 import type { GitHistoryOptions, GitHistoryResult } from '../../shared/git-history'
 import type { CommitMessageDraftContext } from '../../shared/commit-message-generation'
 import type { WorkspaceSpaceDirectoryScanResult } from '../../shared/workspace-space-types'
+import type { StartupCommandDelivery } from '../../shared/codex-startup-delivery'
 
 // ─── PTY Provider ───────────────────────────────────────────────────
 
@@ -28,6 +29,7 @@ export type PtySpawnOptions = {
   env?: Record<string, string>
   envToDelete?: string[]
   command?: string
+  startupCommandDelivery?: StartupCommandDelivery
   /** Orca worktree identity. When present, the local provider scopes shell
    *  history to this worktree so ArrowUp only surfaces local commands. */
   worktreeId?: string
diff --git a/src/main/runtime/orca-runtime.ts b/src/main/runtime/orca-runtime.ts
index e6a63c232..512d642f3 100644
--- a/src/main/runtime/orca-runtime.ts
+++ b/src/main/runtime/orca-runtime.ts
@@ -902,6 +902,7 @@ type RuntimePtyController = {
     rows: number
     cwd?: string
     command?: string
+    startupCommandDelivery?: WorktreeStartupLaunch['startupCommandDelivery']
     env?: Record<string, string>
     envToDelete?: string[]
     telemetry?: WorktreeStartupLaunch['telemetry']
@@ -3161,6 +3162,7 @@ export class OrcaRuntimeService {
             true,
             undefined,
             undefined,
+            undefined,
             {
               tabId: tab.parentTabId,
               leafId: tab.leafId,
@@ -9923,6 +9925,9 @@ export class OrcaRuntimeService {
         agent,
         startup: {
           command: draftLaunchPlan.launchCommand,
+          ...(draftLaunchPlan.startupCommandDelivery
+            ? { startupCommandDelivery: draftLaunchPlan.startupCommandDelivery }
+            : {}),
           ...(draftLaunchPlan.env ? { env: draftLaunchPlan.env } : {})
         }
       }
@@ -9944,6 +9949,9 @@ export class OrcaRuntimeService {
       agent,
       startup: {
         command: startupPlan.launchCommand,
+        ...(startupPlan.startupCommandDelivery
+          ? { startupCommandDelivery: startupPlan.startupCommandDelivery }
+          : {}),
         ...(startupPlan.env ? { env: startupPlan.env } : {})
       },
       draftPaste: { agent, content }
@@ -9981,6 +9989,9 @@ export class OrcaRuntimeService {
       agent,
       startup: {
         command: startupPlan.launchCommand,
+        ...(startupPlan.startupCommandDelivery
+          ? { startupCommandDelivery: startupPlan.startupCommandDelivery }
+          : {}),
         ...(startupPlan.env ? { env: startupPlan.env } : {})
       },
       ...(startupPlan.followupPrompt
@@ -10400,6 +10411,7 @@ export class OrcaRuntimeService {
           const terminal = await this.createTerminal(`id:${worktree.id}`, {
             command: effectiveStartup.command,
             env: effectiveStartup.env,
+            startupCommandDelivery: effectiveStartup.startupCommandDelivery,
             telemetry: effectiveStartup.telemetry
           })
           if (effectiveDraftPaste) {
@@ -10981,6 +10993,7 @@ export class OrcaRuntimeService {
         const terminal = await this.createTerminal(`id:${worktree.id}`, {
           command: effectiveStartup.command,
           env: effectiveStartup.env,
+          startupCommandDelivery: effectiveStartup.startupCommandDelivery,
           telemetry: effectiveStartup.telemetry
         })
         if (effectiveDraftPaste) {
@@ -11237,6 +11250,7 @@ export class OrcaRuntimeService {
         const terminal = await this.createTerminal(`path:${result.worktree.path}`, {
           command: args.startup.command,
           env: args.startup.env,
+          startupCommandDelivery: args.startup.startupCommandDelivery,
           telemetry: args.startup.telemetry
         })
         if (args.startupDraftPaste) {
@@ -12765,6 +12779,7 @@ export class OrcaRuntimeService {
     opts: {
       command?: string
       env?: Record<string, string>
+      startupCommandDelivery?: WorktreeStartupLaunch['startupCommandDelivery']
       telemetry?: WorktreeStartupLaunch['telemetry']
       title?: string
       focus?: boolean
@@ -12842,6 +12857,7 @@ export class OrcaRuntimeService {
         rows: 40,
         cwd: workspace.path,
         command: agentTeamsPlan?.command ?? opts.command,
+        startupCommandDelivery: opts.startupCommandDelivery,
         env,
         envToDelete: agentTeamsPlan?.envToDelete,
         telemetry: opts.telemetry,
@@ -12938,6 +12954,7 @@ export class OrcaRuntimeService {
         requestId,
         worktreeId,
         command: opts.command,
+        startupCommandDelivery: opts.startupCommandDelivery,
         title: opts.title,
         activate: opts.focus === true || opts.activate === true
       })
@@ -12974,6 +12991,7 @@ export class OrcaRuntimeService {
     return await this.createTerminal(`id:${worktree.id}`, {
       command: startup.startup.command,
       env: startup.startup.env,
+      startupCommandDelivery: startup.startup.startupCommandDelivery,
       telemetry: startup.startup.telemetry,
       title: opts.title
     })
@@ -12985,6 +13003,7 @@ export class OrcaRuntimeService {
       afterTabId?: string
       targetGroupId?: string
       command?: string
+      startupCommandDelivery?: WorktreeStartupLaunch['startupCommandDelivery']
       agent?: TuiAgent
       activate?: boolean
     } = {}
@@ -13011,6 +13030,7 @@ export class OrcaRuntimeService {
         opts.activate !== false,
         opts.afterTabId,
         command,
+        opts.startupCommandDelivery,
         undefined,
         opts.agent
       )
@@ -13044,6 +13064,7 @@ export class OrcaRuntimeService {
         afterTabId: afterDesktopTabId,
         targetGroupId: opts.targetGroupId,
         command,
+        startupCommandDelivery: opts.startupCommandDelivery,
         activate: opts.activate
       })
     })
@@ -13100,6 +13121,7 @@ export class OrcaRuntimeService {
     activate: boolean,
     afterTabId?: string,
     command?: string,
+    startupCommandDelivery?: WorktreeStartupLaunch['startupCommandDelivery'],
     identity?: { tabId: string; leafId: string; sessionId?: string },
     launchAgent?: TuiAgent
   ): Promise<RuntimeMobileSessionCreateTerminalResult> {
@@ -13111,6 +13133,7 @@ export class OrcaRuntimeService {
     const terminal = await this.createTerminal(`id:${worktreeId}`, {
       focus: false,
       command,
+      startupCommandDelivery,
       ...(identity
         ? {
             tabId: identity.tabId,
diff --git a/src/main/runtime/rpc/methods/session-tabs.test.ts b/src/main/runtime/rpc/methods/session-tabs.test.ts
index 091747441..20112ef37 100644
--- a/src/main/runtime/rpc/methods/session-tabs.test.ts
+++ b/src/main/runtime/rpc/methods/session-tabs.test.ts
@@ -119,6 +119,7 @@ describe('session tab RPC methods', () => {
       afterTabId: undefined,
       targetGroupId: 'group-left',
       command: 'zsh',
+      startupCommandDelivery: undefined,
       agent: undefined,
       activate: true
     })
@@ -156,11 +157,51 @@ describe('session tab RPC methods', () => {
       afterTabId: undefined,
       targetGroupId: undefined,
       command: undefined,
+      startupCommandDelivery: undefined,
       agent: 'codex',
       activate: undefined
     })
   })
 
+  it('dispatches terminal creation with startup command delivery metadata', async () => {
+    const runtime = {
+      getRuntimeId: () => 'test-runtime',
+      createMobileSessionTerminal: vi.fn().mockResolvedValue({
+        tab: {
+          type: 'terminal',
+          id: 'tab-1::leaf-1',
+          parentTabId: 'tab-1',
+          leafId: 'leaf-1',
+          title: 'Terminal',
+          status: 'ready',
+          terminal: 'pty-1',
+          isActive: true
+        },
+        publicationEpoch: 'epoch-1',
+        snapshotVersion: 1
+      })
+    } as unknown as OrcaRuntimeService
+    const dispatcher = new RpcDispatcher({ runtime, methods: SESSION_TAB_METHODS })
+
+    const response = await dispatcher.dispatch(
+      makeRequest('session.tabs.createTerminal', {
+        worktree: 'id:wt-1',
+        command: "codex 'linked issue context'",
+        startupCommandDelivery: 'shell-ready'
+      })
+    )
+
+    expect(response.ok).toBe(true)
+    expect(runtime.createMobileSessionTerminal).toHaveBeenCalledWith('id:wt-1', {
+      afterTabId: undefined,
+      targetGroupId: undefined,
+      command: "codex 'linked issue context'",
+      startupCommandDelivery: 'shell-ready',
+      agent: undefined,
+      activate: undefined
+    })
+  })
+
   it('rejects unknown agent presets without creating a terminal', async () => {
     const runtime = {
       getRuntimeId: () => 'test-runtime',
diff --git a/src/main/runtime/rpc/methods/session-tabs.ts b/src/main/runtime/rpc/methods/session-tabs.ts
index 55c2df802..19eadfd48 100644
--- a/src/main/runtime/rpc/methods/session-tabs.ts
+++ b/src/main/runtime/rpc/methods/session-tabs.ts
@@ -26,6 +26,7 @@ const CreateTerminalTab = WorktreeTabSelector.extend({
   afterTabId: z.string().optional(),
   targetGroupId: z.string().optional(),
   command: z.string().optional(),
+  startupCommandDelivery: z.enum(['fast', 'shell-ready']).optional(),
   agent: z
     .custom<TuiAgent>(isTuiAgent, {
       message: 'Unknown agent preset'
@@ -111,6 +112,7 @@ export const SESSION_TAB_METHODS: RpcAnyMethod[] = [
         afterTabId: params.afterTabId,
         targetGroupId: params.targetGroupId,
         command: params.command,
+        startupCommandDelivery: params.startupCommandDelivery,
         agent: params.agent,
         activate: params.activate
       })
diff --git a/src/main/runtime/rpc/methods/terminal.ts b/src/main/runtime/rpc/methods/terminal.ts
index 1363fa8c1..24bad0571 100644
--- a/src/main/runtime/rpc/methods/terminal.ts
+++ b/src/main/runtime/rpc/methods/terminal.ts
@@ -507,6 +507,7 @@ const TerminalWait = TerminalHandle.extend({
 const TerminalCreateParams = z.object({
   worktree: OptionalString,
   command: OptionalString,
+  startupCommandDelivery: z.enum(['fast', 'shell-ready']).optional(),
   env: z.record(z.string(), z.string()).optional(),
   title: OptionalString,
   focus: z.unknown().optional(),
@@ -774,6 +775,7 @@ export const TERMINAL_METHODS: RpcAnyMethod[] = [
     handler: async (params, { runtime }) => ({
       terminal: await runtime.createTerminal(params.worktree, {
         command: params.command,
+        startupCommandDelivery: params.startupCommandDelivery,
         env: params.env,
         title: params.title,
         focus: params.focus === true,
diff --git a/src/main/runtime/rpc/methods/worktree-schemas.ts b/src/main/runtime/rpc/methods/worktree-schemas.ts
index 0d3ffeab4..f7c8d9178 100644
--- a/src/main/runtime/rpc/methods/worktree-schemas.ts
+++ b/src/main/runtime/rpc/methods/worktree-schemas.ts
@@ -118,6 +118,7 @@ export const WorktreeCreate = z
     // terminal pane launches the selected agent instead of an idle shell.
     startupCommand: OptionalString,
     startupEnv: z.record(z.string(), z.string()).optional(),
+    startupCommandDelivery: z.enum(['fast', 'shell-ready']).optional(),
     // Why: CLI clients should not hardcode agent launch quoting because SSH
     // workspaces execute in a different shell than the client process.
     startupAgent: OptionalTuiAgent,
diff --git a/src/main/runtime/rpc/methods/worktree.test.ts b/src/main/runtime/rpc/methods/worktree.test.ts
index 1aa6c916e..4b04f8953 100644
--- a/src/main/runtime/rpc/methods/worktree.test.ts
+++ b/src/main/runtime/rpc/methods/worktree.test.ts
@@ -83,6 +83,7 @@ describe('worktree RPC methods', () => {
         repo: 'repo-1',
         name: 'agent-startup',
         startupCommand: "codex 'summarize repo'",
+        startupCommandDelivery: 'shell-ready',
         startupEnv: { ORCA_AGENT_MODE: 'direct' },
         activate: true
       })
@@ -95,6 +96,7 @@ describe('worktree RPC methods', () => {
         activate: true,
         startup: {
           command: "codex 'summarize repo'",
+          startupCommandDelivery: 'shell-ready',
           env: { ORCA_AGENT_MODE: 'direct' }
         }
       })
diff --git a/src/main/runtime/rpc/methods/worktree.ts b/src/main/runtime/rpc/methods/worktree.ts
index 5f09061dc..a707b539e 100644
--- a/src/main/runtime/rpc/methods/worktree.ts
+++ b/src/main/runtime/rpc/methods/worktree.ts
@@ -89,7 +89,10 @@ export const WORKTREE_METHODS: RpcMethod[] = [
         startup: params.startupCommand
           ? {
               command: params.startupCommand,
-              ...(params.startupEnv ? { env: params.startupEnv } : {})
+              ...(params.startupEnv ? { env: params.startupEnv } : {}),
+              ...(params.startupCommandDelivery
+                ? { startupCommandDelivery: params.startupCommandDelivery }
+                : {})
             }
           : undefined,
         ...(params.startupAgent ? { startupAgent: params.startupAgent } : {}),
diff --git a/src/preload/api-types.ts b/src/preload/api-types.ts
index 5d1b470f4..3acbc565d 100644
--- a/src/preload/api-types.ts
+++ b/src/preload/api-types.ts
@@ -13,6 +13,7 @@ import type { AppIdentity } from '../shared/app-identity'
 import type { TerminalPaneSplitSource } from '../shared/feature-education-telemetry'
 import type { TaskSourceContext } from '../shared/task-source-context'
 import type { ProjectExecutionRuntimeResolution } from '../shared/project-execution-runtime'
+import type { StartupCommandDelivery } from '../shared/codex-startup-delivery'
 import type {
   FolderWorkspacePathStatus,
   FolderWorkspacePathStatusRequest
@@ -1014,6 +1015,7 @@ export type PreloadApi = {
       cwd?: string
       env?: Record<string, string>
       command?: string
+      startupCommandDelivery?: StartupCommandDelivery
       connectionId?: string | null
       worktreeId?: string
       sessionId?: string
@@ -2385,6 +2387,7 @@ export type PreloadApi = {
         afterTabId?: string
         targetGroupId?: string
         command?: string
+        startupCommandDelivery?: StartupCommandDelivery
         title?: string
         activate?: boolean
       }) => void
diff --git a/src/preload/index.ts b/src/preload/index.ts
index c1bfee59d..c8df88993 100644
--- a/src/preload/index.ts
+++ b/src/preload/index.ts
@@ -10,6 +10,7 @@ import type { CliInstallStatus } from '../shared/cli-install-types'
 import type { AgentHookInstallStatus } from '../shared/agent-hook-types'
 import type { TerminalPaneSplitSource } from '../shared/feature-education-telemetry'
 import type { ProjectExecutionRuntimeResolution } from '../shared/project-execution-runtime'
+import type { StartupCommandDelivery } from '../shared/codex-startup-delivery'
 import type {
   BaseRefSearchResult,
   BaseRefDefaultResult,
@@ -694,6 +695,7 @@ const api = {
       cwd?: string
       env?: Record<string, string>
       command?: string
+      startupCommandDelivery?: StartupCommandDelivery
       connectionId?: string | null
       worktreeId?: string
       sessionId?: string
@@ -1697,7 +1699,7 @@ const api = {
     copilotStatus: (): Promise<AgentHookInstallStatus> =>
       ipcRenderer.invoke('agentHooks:copilotStatus'),
     hermesStatus: (): Promise<AgentHookInstallStatus> =>
-      ipcRenderer.invoke('agentHooks:hermesStatus'),
+      ipcRenderer.invoke('agentHooks:hermesStatus')
   },
 
   agentTrust: {
@@ -3002,6 +3004,7 @@ const api = {
         afterTabId?: string
         targetGroupId?: string
         command?: string
+        startupCommandDelivery?: StartupCommandDelivery
         title?: string
         activate?: boolean
       }) => void
@@ -3014,6 +3017,7 @@ const api = {
           afterTabId?: string
           targetGroupId?: string
           command?: string
+          startupCommandDelivery?: StartupCommandDelivery
           title?: string
           activate?: boolean
         }
diff --git a/src/relay/pty-handler.test.ts b/src/relay/pty-handler.test.ts
index e063094a3..983ac2348 100644
--- a/src/relay/pty-handler.test.ts
+++ b/src/relay/pty-handler.test.ts
@@ -165,6 +165,76 @@ describe('PtyHandler', () => {
     expect(handler.activePtyCount).toBe(1)
   })
 
+  it.skipIf(process.platform === 'win32')(
+    'enables shell-ready marker env for delivery-hinted startup commands',
+    async () => {
+      const oldShell = process.env.SHELL
+      const oldHome = process.env.HOME
+      const homeDir = mkdtempSync(join(tmpdir(), 'relay-shell-ready-spawn-'))
+
+      process.env.SHELL = '/bin/bash'
+      process.env.HOME = homeDir
+      try {
+        await dispatcher.callRequest('pty.spawn', {
+          env: { HOME: homeDir },
+          startupCommandDelivery: 'shell-ready'
+        })
+      } finally {
+        if (oldShell === undefined) {
+          delete process.env.SHELL
+        } else {
+          process.env.SHELL = oldShell
+        }
+        if (oldHome === undefined) {
+          delete process.env.HOME
+        } else {
+          process.env.HOME = oldHome
+        }
+        rmSync(homeDir, { recursive: true, force: true })
+      }
+
+      const spawnOptions = mockPtySpawn.mock.calls[0]?.[2] as
+        | { env?: Record<string, string> }
+        | undefined
+      expect(spawnOptions?.env?.ORCA_SHELL_READY_MARKER).toBe('1')
+    }
+  )
+
+  it.skipIf(process.platform === 'win32')(
+    'enables shell-ready marker env for Codex native prefill commands',
+    async () => {
+      const oldShell = process.env.SHELL
+      const oldHome = process.env.HOME
+      const homeDir = mkdtempSync(join(tmpdir(), 'relay-codex-prefill-spawn-'))
+
+      process.env.SHELL = '/bin/bash'
+      process.env.HOME = homeDir
+      try {
+        await dispatcher.callRequest('pty.spawn', {
+          env: { HOME: homeDir },
+          command: "codex --prefill 'linked issue context'"
+        })
+      } finally {
+        if (oldShell === undefined) {
+          delete process.env.SHELL
+        } else {
+          process.env.SHELL = oldShell
+        }
+        if (oldHome === undefined) {
+          delete process.env.HOME
+        } else {
+          process.env.HOME = oldHome
+        }
+        rmSync(homeDir, { recursive: true, force: true })
+      }
+
+      const spawnOptions = mockPtySpawn.mock.calls[0]?.[2] as
+        | { env?: Record<string, string> }
+        | undefined
+      expect(spawnOptions?.env?.ORCA_SHELL_READY_MARKER).toBe('1')
+    }
+  )
+
   it('terminates spawned PTY when request becomes stale before response', async () => {
     const killSpy = vi.fn()
     const term = { ...mockPtyInstance, kill: killSpy, onData: vi.fn(), onExit: vi.fn() }
diff --git a/src/relay/pty-handler.ts b/src/relay/pty-handler.ts
index 9f8eb7895..b1419e2fa 100644
--- a/src/relay/pty-handler.ts
+++ b/src/relay/pty-handler.ts
@@ -12,6 +12,7 @@ import {
 } from './pty-shell-utils'
 import { getRelayShellLaunchConfig } from './pty-shell-launch'
 import { DEFAULT_SSH_RELAY_GRACE_PERIOD_SECONDS } from '../shared/ssh-types'
+import { shouldUseShellReadyStartupDelivery } from '../shared/codex-startup-delivery'
 
 // Why: node-pty is a native addon that may not be installed on the remote.
 // Dynamic import keeps the require() lazy so loadPty() returns null gracefully
@@ -433,7 +434,15 @@ export class PtyHandler {
     const paneKey = typeof env?.ORCA_PANE_KEY === 'string' ? env.ORCA_PANE_KEY : undefined
     const command = typeof params.command === 'string' ? params.command : undefined
     const spawnEnv = this.buildSpawnEnv(env, { id, paneKey, shell, command })
-    const shellLaunch = getRelayShellLaunchConfig(shell, spawnEnv)
+    // Why: only explicit shell-ready hints are trusted here; native Codex
+    // prefill detection still auto-enables readiness through the predicate.
+    const shellLaunch = getRelayShellLaunchConfig(shell, spawnEnv, process.platform, {
+      emitReadyMarker: shouldUseShellReadyStartupDelivery({
+        command,
+        startupCommandDelivery:
+          params.startupCommandDelivery === 'shell-ready' ? 'shell-ready' : undefined
+      })
+    })
 
     // Why: SSH exec channels give the relay a minimal environment without
     // .zprofile/.bash_profile sourced. Spawning a login shell ensures PATH
diff --git a/src/relay/pty-shell-launch.test.ts b/src/relay/pty-shell-launch.test.ts
index 775845ca1..9f020b06e 100644
--- a/src/relay/pty-shell-launch.test.ts
+++ b/src/relay/pty-shell-launch.test.ts
@@ -151,6 +151,37 @@ describe('getRelayShellLaunchConfig', () => {
     }
   )
 
+  it.skipIf(process.platform === 'win32')(
+    'enables the shell-ready marker for requested zsh startup delivery',
+    () => {
+      const config = getRelayShellLaunchConfig('/bin/zsh', { HOME: homeDir }, 'linux', {
+        emitReadyMarker: true
+      })
+      const zshRoot = join(homeDir, '.orca-relay', 'shell-ready', 'zsh')
+      const zlogin = readFileSync(join(zshRoot, '.zlogin'), 'utf8')
+
+      expect(config.args).toEqual(['-l'])
+      expect(config.env.ZDOTDIR).toBe(zshRoot)
+      expect(config.env.ORCA_SHELL_READY_MARKER).toBe('1')
+      expect(zlogin).toContain('zle -N zle-line-init __orca_prompt_mark')
+      expect(zlogin).toContain('printf "\\033]777;orca-shell-ready\\007"')
+    }
+  )
+
+  it.skipIf(process.platform === 'win32')(
+    'enables the shell-ready marker for requested bash startup delivery',
+    () => {
+      const config = getRelayShellLaunchConfig('/bin/bash', { HOME: homeDir }, 'linux', {
+        emitReadyMarker: true
+      })
+      const bashRc = readFileSync(config.args[1] as string, 'utf8')
+
+      expect(config.env.ORCA_SHELL_READY_MARKER).toBe('1')
+      expect(bashRc).toContain('__orca_append_prompt_command "__orca_prompt_mark"')
+      expect(bashRc).toContain('printf "\\033]777;orca-shell-ready\\007"')
+    }
+  )
+
   itWithBash('runs the relay bash wrapper without fake C/D markers before the first prompt', () => {
     const config = getRelayShellLaunchConfig('/bin/bash', { HOME: homeDir })
     const output = runInteractiveBashRcfile(config.args[1] as string, homeDir)
diff --git a/src/relay/pty-shell-launch.ts b/src/relay/pty-shell-launch.ts
index fb618283c..a9a3e221c 100644
--- a/src/relay/pty-shell-launch.ts
+++ b/src/relay/pty-shell-launch.ts
@@ -4,11 +4,13 @@ import { dirname, join } from 'path'
 import { getPosixOmpShellWrapper } from '../main/pty/omp-shell-wrapper'
 import {
   getZshFinalZdotdirRestoreBlock,
+  getZshShellReadyMarkerRegistrationBlock,
   getZshStartupFileSourceBlock
 } from '../main/shell-templates'
 
 const RELAY_SHELL_READY_DIR = '.orca-relay/shell-ready'
 const POSIX_LOGIN_ARGS = ['-l']
+const SHELL_READY_MARKER_ESCAPED = '\\033]777;orca-shell-ready\\007'
 
 export type RelayShellLaunchConfig = {
   args: string[]
@@ -116,6 +118,7 @@ ${getZshStartupFileSourceBlock({
 [[ -n "\${ORCA_REMOTE_CLI_BIN_DIR:-}" ]] && case ":$PATH:" in *:"\${ORCA_REMOTE_CLI_BIN_DIR}":*) ;; *) export PATH="\${ORCA_REMOTE_CLI_BIN_DIR}:$PATH" ;; esac
 ${getPosixOmpShellWrapper()}
 ${getZshFinalZdotdirRestoreBlock('"${ORCA_USER_ZDOTDIR:-${ORCA_ORIG_ZDOTDIR:-$HOME}}"')}
+${getZshShellReadyMarkerRegistrationBlock(SHELL_READY_MARKER_ESCAPED)}
 `
   const bashRc = `# Orca relay bash overlay wrapper
 [[ -f /etc/profile ]] && source /etc/profile
@@ -186,6 +189,14 @@ __orca_append_prompt_command() {
   fi
 }
 __orca_prepend_prompt_command
+# Why: SSH startup commands are renderer-delivered; emit the same internal
+# readiness marker as local shells only when that delivery mode asks for it.
+if [[ "\${ORCA_SHELL_READY_MARKER:-0}" == "1" ]]; then
+  __orca_prompt_mark() {
+    printf "${SHELL_READY_MARKER_ESCAPED}"
+  }
+  __orca_append_prompt_command "__orca_prompt_mark"
+fi
 __orca_append_prompt_command "__orca_osc133_prompt_done"
 __orca_debug_trap_spec="$(trap -p DEBUG)"
 if [[ -n "$__orca_debug_trap_spec" ]]; then
@@ -229,9 +240,11 @@ trap '__orca_osc133_preexec' DEBUG
 export function getRelayShellLaunchConfig(
   shellPath: string,
   env: Record<string, string>,
-  platform: NodeJS.Platform = process.platform
+  platform: NodeJS.Platform = process.platform,
+  options: { emitReadyMarker?: boolean } = {}
 ): RelayShellLaunchConfig {
   const shellName = shellBasename(shellPath)
+  const emitReadyMarker = options.emitReadyMarker === true
   if (platform === 'win32') {
     // Why: pwsh also exists on POSIX remotes; Windows-specific shell args must
     // only apply when the relay itself is running on native Windows.
@@ -241,7 +254,9 @@ export function getRelayShellLaunchConfig(
   if (shellName !== 'zsh' && shellName !== 'bash') {
     return { args: POSIX_LOGIN_ARGS, env: {} }
   }
-  if (shellName === 'zsh' && !hasOverlayRestoreEnv(env)) {
+  // Why: preserve plain zsh startup fast path; only force wrappers when
+  // shell-ready or overlay env restoration is requested.
+  if (shellName === 'zsh' && !hasOverlayRestoreEnv(env) && !emitReadyMarker) {
     return { args: POSIX_LOGIN_ARGS, env: {} }
   }
 
@@ -253,13 +268,14 @@ export function getRelayShellLaunchConfig(
       args: POSIX_LOGIN_ARGS,
       env: {
         ORCA_ORIG_ZDOTDIR: resolveOriginalZdotdir(env),
-        ZDOTDIR: join(root, 'zsh')
+        ZDOTDIR: join(root, 'zsh'),
+        ...(emitReadyMarker ? { ORCA_SHELL_READY_MARKER: '1' } : {})
       }
     }
   }
 
   return {
     args: ['--rcfile', join(root, 'bash', 'rcfile')],
-    env: {}
+    env: emitReadyMarker ? { ORCA_SHELL_READY_MARKER: '1' } : {}
   }
 }
diff --git a/src/renderer/src/components/floating-terminal/FloatingTerminalWindowControls.tsx b/src/renderer/src/components/floating-terminal/FloatingTerminalWindowControls.tsx
index e3fd7b00a..4e4248843 100644
--- a/src/renderer/src/components/floating-terminal/FloatingTerminalWindowControls.tsx
+++ b/src/renderer/src/components/floating-terminal/FloatingTerminalWindowControls.tsx
@@ -78,6 +78,9 @@ export function FloatingTerminalWindowControls({
     state.queueTabStartupCommand(tab.id, {
       command: startupPlan.launchCommand,
       ...(startupPlan.env ? { env: startupPlan.env } : {}),
+      ...(startupPlan.startupCommandDelivery
+        ? { startupCommandDelivery: startupPlan.startupCommandDelivery }
+        : {}),
       telemetry: {
         agent_kind: tuiAgentToAgentKind(defaultAgent),
         launch_source: 'shortcut',
diff --git a/src/renderer/src/components/sidebar/folder-workspace-composer-submit.ts b/src/renderer/src/components/sidebar/folder-workspace-composer-submit.ts
index 8620eefbb..deb619212 100644
--- a/src/renderer/src/components/sidebar/folder-workspace-composer-submit.ts
+++ b/src/renderer/src/components/sidebar/folder-workspace-composer-submit.ts
@@ -131,6 +131,9 @@ export async function submitFolderWorkspaceCreate({
       ? {
           command: startupPlan.launchCommand,
           ...(startupPlan.env ? { env: startupPlan.env } : {}),
+          ...(startupPlan.startupCommandDelivery
+            ? { startupCommandDelivery: startupPlan.startupCommandDelivery }
+            : {}),
           telemetry: {
             agent_kind: tuiAgentToAgentKind(quickAgent),
             launch_source: launchSource,
diff --git a/src/renderer/src/components/terminal-pane/pty-connection-types.ts b/src/renderer/src/components/terminal-pane/pty-connection-types.ts
index 0dbadcd88..c3fe8a3e2 100644
--- a/src/renderer/src/components/terminal-pane/pty-connection-types.ts
+++ b/src/renderer/src/components/terminal-pane/pty-connection-types.ts
@@ -3,6 +3,7 @@ import type { ReplayingPanesRef } from './replay-guard'
 import type { AgentCompletionStatusSnapshot } from './agent-completion-coordinator-types'
 import type { EventProps } from '../../../../shared/telemetry-events'
 import type { TerminalColorSchemeMode } from '../../../../shared/terminal-color-scheme-protocol'
+import type { StartupCommandDelivery } from '../../../../shared/codex-startup-delivery'
 import type { TuiAgent } from '../../../../shared/types'
 
 export type PtyConnectionDeps = {
@@ -14,6 +15,7 @@ export type PtyConnectionDeps = {
     /** Renderer-delivered startup input for callers that need xterm paste
      *  semantics before the submit Enter. */
     delivery?: 'terminal-paste'
+    startupCommandDelivery?: StartupCommandDelivery
     env?: Record<string, string>
     /** Telemetry payload for `agent_started`. Forwarded to `pty:spawn`
      *  so main fires the event only after the spawn succeeds. */
diff --git a/src/renderer/src/components/terminal-pane/pty-connection.test.ts b/src/renderer/src/components/terminal-pane/pty-connection.test.ts
index de5bafd3d..ba5a98d19 100644
--- a/src/renderer/src/components/terminal-pane/pty-connection.test.ts
+++ b/src/renderer/src/components/terminal-pane/pty-connection.test.ts
@@ -2432,7 +2432,7 @@ describe('connectPanePty', () => {
     expect(transport.sendInput).not.toHaveBeenCalled()
   })
 
-  it('sends startup command via sendInput for SSH connections (relay has no shell-ready mechanism)', async () => {
+  it('sends fast startup commands via sendInput for SSH connections', async () => {
     // Capture the setTimeout callback directly so we can fire it without
     // vi.useFakeTimers() (which would also replace the rAF mock from beforeEach).
     const pendingTimeouts: (() => void)[] = []
@@ -2457,7 +2457,8 @@ describe('connectPanePty', () => {
       )
       transportFactoryQueue.push(transport)
 
-      // SSH connection: connectionId is set, relay ignores the command field
+      // SSH connection: connectionId is set, relay receives command metadata
+      // for spawn context but the renderer owns fast command delivery.
       mockStoreState = {
         ...mockStoreState,
         tabsByWorktree: { 'wt-1': [{ id: 'tab-1', ptyId: null }] },
@@ -2485,6 +2486,227 @@ describe('connectPanePty', () => {
     }
   })
 
+  it('waits for the SSH shell-ready marker before sending hinted startup commands', async () => {
+    const pendingTimeouts: (() => void)[] = []
+    const originalSetTimeout = globalThis.setTimeout
+    globalThis.setTimeout = vi.fn((fn: () => void) => {
+      pendingTimeouts.push(fn)
+      return 999 as unknown as ReturnType<typeof setTimeout>
+    }) as unknown as typeof setTimeout
+
+    try {
+      const { connectPanePty } = await import('./pty-connection')
+
+      const capturedDataCallback: { current: ((data: string) => void) | null } = {
+        current: null
+      }
+      const transport = createMockTransport('pty-id')
+      transport.connect.mockImplementation(
+        async ({ callbacks }: { callbacks: ConnectCallbacks }) => {
+          capturedDataCallback.current = callbacks.onData ?? null
+          return 'pty-ssh-1'
+        }
+      )
+      transportFactoryQueue.push(transport)
+
+      mockStoreState = {
+        ...mockStoreState,
+        tabsByWorktree: { 'wt-1': [{ id: 'tab-1', ptyId: null }] },
+        repos: [{ id: 'repo1', connectionId: 'ssh-conn-1' }]
+      }
+
+      const pane = createPane(1)
+      const manager = createManager(1)
+      const deps = createDeps({
+        startup: {
+          command: "codex 'linked issue context'",
+          startupCommandDelivery: 'shell-ready'
+        }
+      })
+
+      connectPanePty(pane as never, manager as never, deps as never)
+      expect(capturedDataCallback.current).not.toBeNull()
+
+      capturedDataCallback.current?.('user@remote $ ')
+      for (const fn of pendingTimeouts.splice(0)) {
+        fn()
+      }
+      expect(transport.sendInput).not.toHaveBeenCalled()
+
+      capturedDataCallback.current?.('\x1b]777;orca-shell-ready\x07user@remote $ ')
+      for (const fn of pendingTimeouts.splice(0)) {
+        fn()
+      }
+
+      expect(transport.sendInput).toHaveBeenCalledWith("codex 'linked issue context'\r")
+    } finally {
+      globalThis.setTimeout = originalSetTimeout
+    }
+  })
+
+  it('falls back for SSH shell-ready startup commands when no marker arrives', async () => {
+    const pendingTimeouts: (() => void)[] = []
+    const originalSetTimeout = globalThis.setTimeout
+    globalThis.setTimeout = vi.fn((fn: () => void) => {
+      pendingTimeouts.push(fn)
+      return 999 as unknown as ReturnType<typeof setTimeout>
+    }) as unknown as typeof setTimeout
+
+    try {
+      const { connectPanePty } = await import('./pty-connection')
+
+      const capturedDataCallback: { current: ((data: string) => void) | null } = {
+        current: null
+      }
+      const transport = createMockTransport('pty-id')
+      transport.connect.mockImplementation(
+        async ({ callbacks }: { callbacks: ConnectCallbacks }) => {
+          capturedDataCallback.current = callbacks.onData ?? null
+          return 'pty-ssh-1'
+        }
+      )
+      transportFactoryQueue.push(transport)
+
+      mockStoreState = {
+        ...mockStoreState,
+        tabsByWorktree: { 'wt-1': [{ id: 'tab-1', ptyId: null }] },
+        repos: [{ id: 'repo1', connectionId: 'ssh-conn-1' }]
+      }
+
+      const pane = createPane(1)
+      const manager = createManager(1)
+      const deps = createDeps({
+        startup: {
+          command: "codex 'linked issue context'",
+          startupCommandDelivery: 'shell-ready'
+        }
+      })
+
+      connectPanePty(pane as never, manager as never, deps as never)
+      capturedDataCallback.current?.('fish prompt> ')
+
+      expect(transport.sendInput).not.toHaveBeenCalled()
+      for (const fn of pendingTimeouts.splice(0)) {
+        fn()
+      }
+      for (const fn of pendingTimeouts.splice(0)) {
+        fn()
+      }
+
+      expect(transport.sendInput).toHaveBeenCalledWith("codex 'linked issue context'\r")
+    } finally {
+      globalThis.setTimeout = originalSetTimeout
+    }
+  })
+
+  it('falls back for quiet SSH shell-ready startup commands with no output', async () => {
+    const pendingTimeouts: (() => void)[] = []
+    const originalSetTimeout = globalThis.setTimeout
+    globalThis.setTimeout = vi.fn((fn: () => void) => {
+      pendingTimeouts.push(fn)
+      return 999 as unknown as ReturnType<typeof setTimeout>
+    }) as unknown as typeof setTimeout
+
+    try {
+      const { connectPanePty } = await import('./pty-connection')
+
+      const capturedDataCallback: { current: ((data: string) => void) | null } = {
+        current: null
+      }
+      const transport = createMockTransport('pty-id')
+      transport.connect.mockImplementation(
+        async ({ callbacks }: { callbacks: ConnectCallbacks }) => {
+          capturedDataCallback.current = callbacks.onData ?? null
+          return 'pty-ssh-1'
+        }
+      )
+      transportFactoryQueue.push(transport)
+
+      mockStoreState = {
+        ...mockStoreState,
+        tabsByWorktree: { 'wt-1': [{ id: 'tab-1', ptyId: null }] },
+        repos: [{ id: 'repo1', connectionId: 'ssh-conn-1' }]
+      }
+
+      const pane = createPane(1)
+      const manager = createManager(1)
+      const deps = createDeps({
+        startup: {
+          command: "codex 'linked issue context'",
+          startupCommandDelivery: 'shell-ready'
+        }
+      })
+
+      connectPanePty(pane as never, manager as never, deps as never)
+      await flushAsyncTicks()
+      expect(capturedDataCallback.current).not.toBeNull()
+      expect(transport.sendInput).not.toHaveBeenCalled()
+
+      for (const fn of pendingTimeouts.splice(0)) {
+        fn()
+      }
+      for (const fn of pendingTimeouts.splice(0)) {
+        fn()
+      }
+
+      expect(transport.sendInput).toHaveBeenCalledWith("codex 'linked issue context'\r")
+    } finally {
+      globalThis.setTimeout = originalSetTimeout
+    }
+  })
+
+  it('waits for shell-ready for SSH Codex native prefill commands without an explicit hint', async () => {
+    const pendingTimeouts: (() => void)[] = []
+    const originalSetTimeout = globalThis.setTimeout
+    globalThis.setTimeout = vi.fn((fn: () => void) => {
+      pendingTimeouts.push(fn)
+      return 999 as unknown as ReturnType<typeof setTimeout>
+    }) as unknown as typeof setTimeout
+
+    try {
+      const { connectPanePty } = await import('./pty-connection')
+
+      const capturedDataCallback: { current: ((data: string) => void) | null } = {
+        current: null
+      }
+      const transport = createMockTransport('pty-id')
+      transport.connect.mockImplementation(
+        async ({ callbacks }: { callbacks: ConnectCallbacks }) => {
+          capturedDataCallback.current = callbacks.onData ?? null
+          return 'pty-ssh-1'
+        }
+      )
+      transportFactoryQueue.push(transport)
+      mockStoreState = {
+        ...mockStoreState,
+        tabsByWorktree: { 'wt-1': [{ id: 'tab-1', ptyId: null }] },
+        repos: [{ id: 'repo1', connectionId: 'ssh-conn-1' }]
+      }
+
+      const pane = createPane(1)
+      const manager = createManager(1)
+      const deps = createDeps({
+        startup: { command: "codex --prefill 'linked issue context'" }
+      })
+
+      connectPanePty(pane as never, manager as never, deps as never)
+      capturedDataCallback.current?.('user@remote $ ')
+      for (const fn of pendingTimeouts.splice(0)) {
+        fn()
+      }
+      expect(transport.sendInput).not.toHaveBeenCalled()
+
+      capturedDataCallback.current?.('\x1b]777;orca-shell-ready\x07user@remote $ ')
+      for (const fn of pendingTimeouts.splice(0)) {
+        fn()
+      }
+
+      expect(transport.sendInput).toHaveBeenCalledWith("codex --prefill 'linked issue context'\r")
+    } finally {
+      globalThis.setTimeout = originalSetTimeout
+    }
+  })
+
   it('drops agent status without retaining when OSC 133 reports the command finished', async () => {
     const { connectPanePty } = await import('./pty-connection')
 
diff --git a/src/renderer/src/components/terminal-pane/pty-connection.ts b/src/renderer/src/components/terminal-pane/pty-connection.ts
index ce020e799..72d69b3a9 100644
--- a/src/renderer/src/components/terminal-pane/pty-connection.ts
+++ b/src/renderer/src/components/terminal-pane/pty-connection.ts
@@ -37,6 +37,8 @@ import {
   POST_REPLAY_REATTACH_RESET,
   RESET_TERMINAL_CURSOR_STYLE
 } from './layout-serialization'
+import { createShellReadyMarkerScanState, scanForShellReadyMarker } from './shell-ready-marker-scan'
+import { shouldUseShellReadyStartupDelivery } from '../../../../shared/codex-startup-delivery'
 import { getSystemPrefersDark } from '@/lib/terminal-theme'
 import {
   mode2031SequenceFor,
@@ -114,6 +116,7 @@ const AGENT_TASK_COMPLETE_NOTIFICATION_GRACE_MS = 250
 const AGENT_TASK_COMPLETE_NOTIFICATION_MAX_WAIT_MS = 1500
 const AGENT_TASK_COMPLETE_NOTIFICATION_DETAIL_MAX_AGE_MS = 10_000
 const COMMAND_CODE_OUTPUT_DONE_SETTLE_MS = 1500
+const SSH_SHELL_READY_STARTUP_FALLBACK_MS = 1500
 const HIDDEN_OUTPUT_RESTORE_SCROLLBACK_ROWS = 5000
 const HIDDEN_OUTPUT_RESTORE_PENDING_CHARS = 512 * 1024
 const HIDDEN_OUTPUT_RESTORE_DEFERRED_RETRY_MS = 50
@@ -793,6 +796,7 @@ export function connectPanePty(
   let cleanupHiddenOutputRestoreDeferredRetry = (): void => {}
   let unregisterE2ePtyDataInjection = (): void => {}
   let startupInjectTimer: ReturnType<typeof setTimeout> | null = null
+  let sshShellReadyFallbackTimer: ReturnType<typeof setTimeout> | null = null
   let agentTaskCompleteNotificationGraceTimer: ReturnType<typeof setTimeout> | null = null
   let agentTaskCompleteNotificationMaxTimer: ReturnType<typeof setTimeout> | null = null
   let agentTaskCompleteStatusUnsubscribe: (() => void) | null = null
@@ -1666,6 +1670,9 @@ export function connectPanePty(
     cwd: deps.cwd,
     env: paneEnv,
     command: shouldDeliverStartupViaTerminalPaste ? undefined : paneStartup?.command,
+    startupCommandDelivery: shouldDeliverStartupViaTerminalPaste
+      ? undefined
+      : paneStartup?.startupCommandDelivery,
     connectionId,
     worktreeId: deps.worktreeId,
     // Why: closes the SIGKILL race documented in INVESTIGATION.md by letting
@@ -1989,10 +1996,32 @@ export function connectPanePty(
     }
 
     // Why: for ordinary local startup commands, the local PTY provider already
-    // writes via the shell-ready barrier. terminal-paste startup commands must
-    // stay renderer-delivered so xterm can apply bracketed-paste semantics.
+    // writes via the shell-ready barrier. terminal-paste and SSH startup
+    // commands stay renderer-delivered so xterm/relay can apply their handling.
     let pendingStartupCommand =
       shouldDeliverStartupViaTerminalPaste || connectionId ? (paneStartup?.command ?? null) : null
+    const shouldWaitForSshShellReady =
+      Boolean(connectionId) &&
+      shouldUseShellReadyStartupDelivery({
+        command: paneStartup?.command,
+        startupCommandDelivery: paneStartup?.startupCommandDelivery
+      }) &&
+      !shouldDeliverStartupViaTerminalPaste
+    const sshShellReadyMarkerScan = shouldWaitForSshShellReady
+      ? createShellReadyMarkerScanState()
+      : null
+    let sshStartupShellReady = !shouldWaitForSshShellReady
+    const markSshStartupShellReady = (): void => {
+      if (sshStartupShellReady) {
+        return
+      }
+      sshStartupShellReady = true
+      if (sshShellReadyFallbackTimer !== null) {
+        clearTimeout(sshShellReadyFallbackTimer)
+        sshShellReadyFallbackTimer = null
+      }
+      schedulePendingStartupCommandDelivery()
+    }
     let sessionRestoredBannerShown = false
     const showSessionRestoredBanner = (): void => {
       if (sessionRestoredBannerShown) {
@@ -2057,6 +2086,18 @@ export function connectPanePty(
       if (!pendingStartupCommand) {
         return
       }
+      if (!sshStartupShellReady) {
+        if (sshShellReadyFallbackTimer === null) {
+          // Why: some SSH shells cannot emit Orca's ready marker. Prefer the
+          // marker when available, but fall back to the old renderer delivery
+          // behavior instead of dropping the startup command forever.
+          sshShellReadyFallbackTimer = setTimeout(() => {
+            sshShellReadyFallbackTimer = null
+            markSshStartupShellReady()
+          }, SSH_SHELL_READY_STARTUP_FALLBACK_MS)
+        }
+        return
+      }
       if (startupInjectTimer !== null) {
         clearTimeout(startupInjectTimer)
       }
@@ -2124,6 +2165,9 @@ export function connectPanePty(
           } else if (typeof gen === 'number') {
             void window.api.pty.clearPendingPaneSerializer(cacheKey, gen).catch(() => {})
           }
+          if (resolvedPtyId && connectionId) {
+            schedulePendingStartupCommandDelivery()
+          }
           return resolvedPtyId
         })
         .catch(async () => {
@@ -2983,6 +3027,13 @@ export function connectPanePty(
         hasReceivedPtyOutput = true
         recordAgentHibernationPaneOutput(cacheKey)
       }
+      if (sshShellReadyMarkerScan) {
+        const scanned = scanForShellReadyMarker(sshShellReadyMarkerScan, data)
+        if (scanned.matched) {
+          markSshStartupShellReady()
+        }
+        data = scanned.output
+      }
       resetHiddenOutputRestoreIfPtyChanged()
       respondToTerminalPixelSizeQueries(data)
       observeTerminalBracketedPasteModeOutput(pane.terminal, data)
@@ -3706,6 +3757,10 @@ export function connectPanePty(
         clearTimeout(startupInjectTimer)
         startupInjectTimer = null
       }
+      if (sshShellReadyFallbackTimer !== null) {
+        clearTimeout(sshShellReadyFallbackTimer)
+        sshShellReadyFallbackTimer = null
+      }
       clearPendingAgentTaskCompleteNotification()
       pendingTerminalBellNotification = false
       clearTerminalBellNotificationTimer()
diff --git a/src/renderer/src/components/terminal-pane/pty-dispatcher.ts b/src/renderer/src/components/terminal-pane/pty-dispatcher.ts
index 63044ad51..916fe63c3 100644
--- a/src/renderer/src/components/terminal-pane/pty-dispatcher.ts
+++ b/src/renderer/src/components/terminal-pane/pty-dispatcher.ts
@@ -8,6 +8,7 @@
 import type { ParsedAgentStatusPayload } from '../../../../shared/agent-status-types'
 import type { EventProps } from '../../../../shared/telemetry-events'
 import type { ProjectExecutionRuntimeResolution } from '../../../../shared/project-execution-runtime'
+import type { StartupCommandDelivery } from '../../../../shared/codex-startup-delivery'
 import { ackPtyData, exposeE2eTerminalPtyAckGate } from './terminal-pty-ack-gate'
 
 // ── Singleton PTY event dispatcher ───────────────────────────────────
@@ -353,6 +354,7 @@ export type IpcPtyTransportOptions = {
   cwd?: string
   env?: Record<string, string>
   command?: string
+  startupCommandDelivery?: StartupCommandDelivery
   connectionId?: string | null
   /** Orca worktree identity for scoped shell history. */
   worktreeId?: string
diff --git a/src/renderer/src/components/terminal-pane/pty-transport.ts b/src/renderer/src/components/terminal-pane/pty-transport.ts
index d07b9de9f..00eb8dd54 100644
--- a/src/renderer/src/components/terminal-pane/pty-transport.ts
+++ b/src/renderer/src/components/terminal-pane/pty-transport.ts
@@ -421,6 +421,7 @@ export function createIpcPtyTransport(opts: IpcPtyTransportOptions = {}): PtyTra
     cwd,
     env,
     command,
+    startupCommandDelivery,
     connectionId,
     worktreeId,
     tabId,
@@ -543,6 +544,7 @@ export function createIpcPtyTransport(opts: IpcPtyTransportOptions = {}): PtyTra
           cwd,
           env,
           command,
+          ...(startupCommandDelivery ? { startupCommandDelivery } : {}),
           ...(connectionId ? { connectionId } : {}),
           ...(options.sessionId ? { sessionId: options.sessionId } : {}),
           worktreeId,
diff --git a/src/renderer/src/components/terminal-pane/remote-runtime-pty-transport.test.ts b/src/renderer/src/components/terminal-pane/remote-runtime-pty-transport.test.ts
index b861e3ee8..2eda1a0d0 100644
--- a/src/renderer/src/components/terminal-pane/remote-runtime-pty-transport.test.ts
+++ b/src/renderer/src/components/terminal-pane/remote-runtime-pty-transport.test.ts
@@ -342,6 +342,30 @@ describe('createRemoteRuntimePtyTransport', () => {
     )
   })
 
+  it('passes startup command delivery when creating the remote runtime terminal', async () => {
+    const { createRemoteRuntimePtyTransport } = await import('./remote-runtime-pty-transport')
+    const transport = createRemoteRuntimePtyTransport('env-1', {
+      worktreeId: 'wt-1',
+      tabId: 'tab-1',
+      leafId: 'pane:1',
+      command: "codex 'linked issue context'",
+      startupCommandDelivery: 'shell-ready'
+    })
+
+    await transport.connect({ url: '', callbacks: {} })
+
+    expect(runtimeCall).toHaveBeenCalledWith(
+      expect.objectContaining({
+        selector: 'env-1',
+        method: 'terminal.create',
+        params: expect.objectContaining({
+          command: "codex 'linked issue context'",
+          startupCommandDelivery: 'shell-ready'
+        })
+      })
+    )
+  })
+
   it('activates pending host session mirrors instead of creating duplicate terminals', async () => {
     runtimeCall.mockImplementation((args) => {
       if (args.method === 'session.tabs.activate') {
diff --git a/src/renderer/src/components/terminal-pane/remote-runtime-pty-transport.ts b/src/renderer/src/components/terminal-pane/remote-runtime-pty-transport.ts
index ea80c70cf..6d15565f6 100644
--- a/src/renderer/src/components/terminal-pane/remote-runtime-pty-transport.ts
+++ b/src/renderer/src/components/terminal-pane/remote-runtime-pty-transport.ts
@@ -47,6 +47,7 @@ export function createRemoteRuntimePtyTransport(
 ): PtyTransport {
   const {
     command,
+    startupCommandDelivery,
     env,
     worktreeId,
     tabId,
@@ -375,6 +376,7 @@ export function createRemoteRuntimePtyTransport(
         const created = await callRuntime<{ terminal: RuntimeTerminalCreate }>('terminal.create', {
           worktree: toRuntimeWorktreeSelector(worktreeId),
           command,
+          startupCommandDelivery,
           env,
           tabId,
           leafId,
diff --git a/src/renderer/src/components/terminal-pane/shell-ready-marker-scan.test.ts b/src/renderer/src/components/terminal-pane/shell-ready-marker-scan.test.ts
new file mode 100644
index 000000000..c364b5a5d
--- /dev/null
+++ b/src/renderer/src/components/terminal-pane/shell-ready-marker-scan.test.ts
@@ -0,0 +1,39 @@
+import { describe, expect, it } from 'vitest'
+import { createShellReadyMarkerScanState, scanForShellReadyMarker } from './shell-ready-marker-scan'
+
+describe('scanForShellReadyMarker', () => {
+  it('strips the marker and preserves surrounding output', () => {
+    const state = createShellReadyMarkerScanState()
+
+    expect(scanForShellReadyMarker(state, 'before \x1b]777;orca-shell-ready\x07 after')).toEqual({
+      output: 'before  after',
+      matched: true
+    })
+  })
+
+  it('matches markers split across chunks', () => {
+    const state = createShellReadyMarkerScanState()
+
+    expect(scanForShellReadyMarker(state, 'before \x1b]777;orca')).toEqual({
+      output: 'before ',
+      matched: false
+    })
+    expect(scanForShellReadyMarker(state, '-shell-ready\x07 after')).toEqual({
+      output: ' after',
+      matched: true
+    })
+  })
+
+  it('flushes marker-like output when the full marker is not BEL-terminated', () => {
+    const state = createShellReadyMarkerScanState()
+
+    expect(scanForShellReadyMarker(state, 'before \x1b]777;orca-shell-readyx')).toEqual({
+      output: 'before \x1b]777;orca-shell-readyx',
+      matched: false
+    })
+    expect(scanForShellReadyMarker(state, ' after')).toEqual({
+      output: ' after',
+      matched: false
+    })
+  })
+})
diff --git a/src/renderer/src/components/terminal-pane/shell-ready-marker-scan.ts b/src/renderer/src/components/terminal-pane/shell-ready-marker-scan.ts
new file mode 100644
index 000000000..9b5b71956
--- /dev/null
+++ b/src/renderer/src/components/terminal-pane/shell-ready-marker-scan.ts
@@ -0,0 +1,54 @@
+const SHELL_READY_MARKER = '\x1b]777;orca-shell-ready'
+
+export type ShellReadyMarkerScanState = {
+  matchPos: number
+  heldBytes: string
+}
+
+export function createShellReadyMarkerScanState(): ShellReadyMarkerScanState {
+  return { matchPos: 0, heldBytes: '' }
+}
+
+export function scanForShellReadyMarker(
+  state: ShellReadyMarkerScanState,
+  data: string
+): { output: string; matched: boolean } {
+  let output = ''
+
+  for (let i = 0; i < data.length; i += 1) {
+    const ch = data[i] as string
+    if (state.matchPos < SHELL_READY_MARKER.length) {
+      if (ch === SHELL_READY_MARKER[state.matchPos]) {
+        state.heldBytes += ch
+        state.matchPos += 1
+      } else {
+        output += state.heldBytes
+        state.heldBytes = ''
+        state.matchPos = 0
+        if (ch === SHELL_READY_MARKER[0]) {
+          state.heldBytes = ch
+          state.matchPos = 1
+        } else {
+          output += ch
+        }
+      }
+    } else if (ch === '\x07') {
+      const remaining = data.slice(i + 1)
+      state.heldBytes = ''
+      state.matchPos = 0
+      return { output: output + remaining, matched: true }
+    } else {
+      output += state.heldBytes
+      state.heldBytes = ''
+      state.matchPos = 0
+      if (ch === SHELL_READY_MARKER[0]) {
+        state.heldBytes = ch
+        state.matchPos = 1
+      } else {
+        output += ch
+      }
+    }
+  }
+
+  return { output, matched: false }
+}
diff --git a/src/renderer/src/components/terminal-pane/use-terminal-pane-lifecycle.ts b/src/renderer/src/components/terminal-pane/use-terminal-pane-lifecycle.ts
index 9e80206fa..f2d49cf79 100644
--- a/src/renderer/src/components/terminal-pane/use-terminal-pane-lifecycle.ts
+++ b/src/renderer/src/components/terminal-pane/use-terminal-pane-lifecycle.ts
@@ -28,6 +28,7 @@ import type {
 } from '../../../../shared/types'
 import type { TerminalPaneSplitSource } from '../../../../shared/feature-education-telemetry'
 import type { EventProps } from '../../../../shared/telemetry-events'
+import type { StartupCommandDelivery } from '../../../../shared/codex-startup-delivery'
 import { resolveTerminalFontWeights } from '../../../../shared/terminal-fonts'
 import {
   buildFontFamily,
@@ -120,6 +121,7 @@ type UseTerminalPaneLifecycleDeps = {
     /** Renderer-delivered startup input for callers that need xterm paste
      *  semantics before the submit Enter. */
     delivery?: 'terminal-paste'
+    startupCommandDelivery?: StartupCommandDelivery
     env?: Record<string, string>
     /** Telemetry payload for `agent_started`. Forwarded to `pty:spawn`
      *  so main fires the event only after the spawn succeeds. */
diff --git a/src/renderer/src/hooks/useComposerState.ts b/src/renderer/src/hooks/useComposerState.ts
index cddf4f312..2f403add1 100644
--- a/src/renderer/src/hooks/useComposerState.ts
+++ b/src/renderer/src/hooks/useComposerState.ts
@@ -2892,6 +2892,9 @@ export function useComposerState(options: UseComposerStateOptions): UseComposerS
           ? {
               command: startupPlan.launchCommand,
               ...(startupPlan.env ? { env: startupPlan.env } : {}),
+              ...(startupPlan.startupCommandDelivery
+                ? { startupCommandDelivery: startupPlan.startupCommandDelivery }
+                : {}),
               telemetry: composerTelemetry
             }
           : undefined
@@ -2954,6 +2957,9 @@ export function useComposerState(options: UseComposerStateOptions): UseComposerS
               startup: {
                 command: startupPlan.launchCommand,
                 ...(startupPlan.env ? { env: startupPlan.env } : {}),
+                ...(startupPlan.startupCommandDelivery
+                  ? { startupCommandDelivery: startupPlan.startupCommandDelivery }
+                  : {}),
                 ...(tuiAgent === 'command-code' && submitStartupPrompt.trim().length > 0
                   ? {
                       initialAgentStatus: {
@@ -3195,6 +3201,9 @@ export function useComposerState(options: UseComposerStateOptions): UseComposerS
             launchCommand: draftLaunchPlan.launchCommand,
             expectedProcess: draftLaunchPlan.expectedProcess,
             followupPrompt: null,
+            ...(draftLaunchPlan.startupCommandDelivery
+              ? { startupCommandDelivery: draftLaunchPlan.startupCommandDelivery }
+              : {}),
             ...(draftLaunchPlan.env ? { env: draftLaunchPlan.env } : {})
           }
         } else if (agent !== null) {
@@ -3226,6 +3235,9 @@ export function useComposerState(options: UseComposerStateOptions): UseComposerS
             ? {
                 command: startupPlan.launchCommand,
                 ...(startupPlan.env ? { env: startupPlan.env } : {}),
+                ...(startupPlan.startupCommandDelivery
+                  ? { startupCommandDelivery: startupPlan.startupCommandDelivery }
+                  : {}),
                 ...(quickTelemetry ? { telemetry: quickTelemetry } : {})
               }
             : undefined
diff --git a/src/renderer/src/hooks/useIpcEvents.ts b/src/renderer/src/hooks/useIpcEvents.ts
index 7ecae27ec..f536bcc30 100644
--- a/src/renderer/src/hooks/useIpcEvents.ts
+++ b/src/renderer/src/hooks/useIpcEvents.ts
@@ -1491,7 +1491,12 @@ export function useIpcEvents(): void {
             store.setTabCustomTitle(tab.id, data.title, { recordInteraction: false })
           }
           if (data.command) {
-            store.queueTabStartupCommand(tab.id, { command: data.command })
+            store.queueTabStartupCommand(tab.id, {
+              command: data.command,
+              ...(data.startupCommandDelivery
+                ? { startupCommandDelivery: data.startupCommandDelivery }
+                : {})
+            })
           }
           window.api.ui.replyTerminalCreate({
             requestId: data.requestId,
diff --git a/src/renderer/src/lib/launch-agent-background-session.test.ts b/src/renderer/src/lib/launch-agent-background-session.test.ts
index 11fea568f..8e398004e 100644
--- a/src/renderer/src/lib/launch-agent-background-session.test.ts
+++ b/src/renderer/src/lib/launch-agent-background-session.test.ts
@@ -355,7 +355,7 @@ describe('launchAgentBackgroundSession', () => {
     )
   })
 
-  it('injects startup commands into SSH background sessions after shell output arrives', async () => {
+  it('injects fast startup commands into SSH background sessions after shell output arrives', async () => {
     vi.useFakeTimers()
     try {
       state.repos = [{ id: 'repo-1', connectionId: 'ssh-1', path: '/repo' }]
@@ -368,7 +368,10 @@ describe('launchAgentBackgroundSession', () => {
         title: 'Nightly audit'
       })
 
-      expect(mockSpawn.mock.calls[0]?.[0]?.command).toBeUndefined()
+      expect(mockSpawn.mock.calls[0]?.[0]?.command).toBe(
+        "claude '--dangerously-skip-permissions' 'run the automation'"
+      )
+      expect(mockSpawn.mock.calls[0]?.[0]?.startupCommandDelivery).toBeUndefined()
       const dataSidecar = mockSubscribeToPtyData.mock.calls[0]?.[1] as (data: string) => void
       dataSidecar('user@remote repo % ')
       vi.advanceTimersByTime(50)
@@ -382,6 +385,108 @@ describe('launchAgentBackgroundSession', () => {
     }
   })
 
+  it('waits for shell-ready before injecting payload-bearing SSH background commands', async () => {
+    vi.useFakeTimers()
+    try {
+      state.repos = [{ id: 'repo-1', connectionId: 'ssh-1', path: '/repo' }]
+      const { launchAgentBackgroundSession } = await import('./launch-agent-background-session')
+
+      await launchAgentBackgroundSession({
+        agent: 'codex',
+        worktreeId: 'wt-1',
+        prompt: 'run the automation',
+        title: 'Nightly audit'
+      })
+
+      expect(mockSpawn.mock.calls[0]?.[0]).toEqual(
+        expect.objectContaining({
+          command: "codex '--dangerously-bypass-approvals-and-sandbox' 'run the automation'",
+          startupCommandDelivery: 'shell-ready'
+        })
+      )
+      const dataSidecar = mockSubscribeToPtyData.mock.calls[0]?.[1] as (data: string) => void
+      dataSidecar('user@remote repo % ')
+      vi.advanceTimersByTime(50)
+      expect(mockWrite).not.toHaveBeenCalled()
+
+      dataSidecar('\x1b]777;orca-shell-ready\x07user@remote repo % ')
+      vi.advanceTimersByTime(50)
+
+      expect(mockWrite).toHaveBeenCalledWith(
+        'pty-1',
+        "codex '--dangerously-bypass-approvals-and-sandbox' 'run the automation'\r"
+      )
+    } finally {
+      vi.useRealTimers()
+    }
+  })
+
+  it('waits for shell-ready for SSH background Codex native prefill commands without a hint', async () => {
+    vi.useFakeTimers()
+    try {
+      state.repos = [{ id: 'repo-1', connectionId: 'ssh-1', path: '/repo' }]
+      state.settings = {
+        agentCmdOverrides: { codex: "codex --prefill 'draft from override'" },
+        activeRuntimeEnvironmentId: null
+      }
+      const { launchAgentBackgroundSession } = await import('./launch-agent-background-session')
+
+      await launchAgentBackgroundSession({
+        agent: 'codex',
+        worktreeId: 'wt-1',
+        title: 'Nightly audit'
+      })
+
+      expect(mockSpawn.mock.calls[0]?.[0]).toEqual(
+        expect.objectContaining({
+          command:
+            "codex --prefill 'draft from override' '--dangerously-bypass-approvals-and-sandbox'"
+        })
+      )
+      expect(mockSpawn.mock.calls[0]?.[0]).not.toHaveProperty('startupCommandDelivery')
+      const dataSidecar = mockSubscribeToPtyData.mock.calls[0]?.[1] as (data: string) => void
+      dataSidecar('user@remote repo % ')
+      vi.advanceTimersByTime(50)
+      expect(mockWrite).not.toHaveBeenCalled()
+
+      dataSidecar('\x1b]777;orca-shell-ready\x07user@remote repo % ')
+      vi.advanceTimersByTime(50)
+
+      expect(mockWrite).toHaveBeenCalledWith(
+        'pty-1',
+        "codex --prefill 'draft from override' '--dangerously-bypass-approvals-and-sandbox'\r"
+      )
+    } finally {
+      vi.useRealTimers()
+    }
+  })
+
+  it('does not rearm SSH background startup delivery after exit cleanup', async () => {
+    vi.useFakeTimers()
+    try {
+      state.repos = [{ id: 'repo-1', connectionId: 'ssh-1', path: '/repo' }]
+      const { launchAgentBackgroundSession } = await import('./launch-agent-background-session')
+
+      await launchAgentBackgroundSession({
+        agent: 'codex',
+        worktreeId: 'wt-1',
+        prompt: 'run the automation',
+        title: 'Nightly audit'
+      })
+
+      const dataSidecar = mockSubscribeToPtyData.mock.calls[0]?.[1] as (data: string) => void
+      const exitSidecar = mockSubscribeToPtyExit.mock.calls[0]?.[1] as (code: number) => void
+      exitSidecar(0)
+
+      dataSidecar('\x1b]777;orca-shell-ready\x07user@remote repo % ')
+      vi.advanceTimersByTime(50)
+
+      expect(mockWrite).not.toHaveBeenCalled()
+    } finally {
+      vi.useRealTimers()
+    }
+  })
+
   it('creates background sessions on the active runtime environment', async () => {
     state.settings = { agentCmdOverrides: {}, activeRuntimeEnvironmentId: 'env-1' }
     const { launchAgentBackgroundSession } = await import('./launch-agent-background-session')
diff --git a/src/renderer/src/lib/launch-agent-background-session.ts b/src/renderer/src/lib/launch-agent-background-session.ts
index 1977bc9c5..0e95c0753 100644
--- a/src/renderer/src/lib/launch-agent-background-session.ts
+++ b/src/renderer/src/lib/launch-agent-background-session.ts
@@ -33,6 +33,8 @@ import { createAgentStatusOscProcessor } from '../../../shared/agent-status-osc'
 import type { ParsedAgentStatusPayload } from '../../../shared/agent-status-types'
 import type { RuntimeTerminalCreate } from '../../../shared/runtime-types'
 import { translate } from '@/i18n/i18n'
+import { createSshBackgroundStartupDelivery } from '@/lib/ssh-background-startup-delivery'
+import { shouldUseShellReadyStartupDelivery } from '../../../shared/codex-startup-delivery'
 
 export type LaunchAgentBackgroundSessionArgs = {
   agent: TuiAgent
@@ -138,39 +140,22 @@ export async function launchAgentBackgroundSession(
     ORCA_WORKTREE_ID: worktreeId
   }
   const sshConnectionId = repo?.connectionId ?? null
-  let pendingSshStartupCommand = sshConnectionId ? startupPlan.launchCommand : null
-  let sshStartupInjectTimer: ReturnType<typeof setTimeout> | null = null
-  const clearSshStartupInjectTimer = (): void => {
-    if (sshStartupInjectTimer !== null) {
-      clearTimeout(sshStartupInjectTimer)
-      sshStartupInjectTimer = null
-    }
-  }
-  const scheduleSshStartupInjection = (ptyId: string): void => {
-    if (!pendingSshStartupCommand) {
-      return
-    }
-    clearSshStartupInjectTimer()
-    sshStartupInjectTimer = setTimeout(() => {
-      sshStartupInjectTimer = null
-      const command = pendingSshStartupCommand
-      if (!command) {
-        return
-      }
-      pendingSshStartupCommand = null
-      // Why: the SSH relay ignores spawn.command for interactive PTYs; hidden
-      // automation tabs must type the startup command themselves after shell output.
-      const submittedCommand =
-        command.endsWith('\r') || command.endsWith('\n') ? command : `${command}\r`
-      window.api.pty.write(ptyId, submittedCommand)
-    }, 50)
-  }
+  const sshStartupDelivery = createSshBackgroundStartupDelivery({
+    command: sshConnectionId ? startupPlan.launchCommand : null,
+    waitForShellReady:
+      Boolean(sshConnectionId) &&
+      shouldUseShellReadyStartupDelivery({
+        command: startupPlan.launchCommand,
+        startupCommandDelivery: startupPlan.startupCommandDelivery
+      }),
+    write: (ptyId, data) => window.api.pty.write(ptyId, data)
+  })
   // Route by the worktree's owner host: the agent terminal must spawn on the host
   // that owns this worktree, not on the focused runtime.
   const runtimeTarget = getActiveRuntimeTarget(
     getSettingsForWorktreeRuntimeOwner(store, worktreeId)
   )
-  let ptyId: string
+  let ptyId = ''
   try {
     if (runtimeTarget.kind === 'environment') {
       // Why: runtime environments execute on the server; using local pty.spawn
@@ -181,6 +166,9 @@ export async function launchAgentBackgroundSession(
         {
           worktree: toRuntimeWorktreeSelector(worktreeId),
           command: startupPlan.launchCommand,
+          ...(startupPlan.startupCommandDelivery
+            ? { startupCommandDelivery: startupPlan.startupCommandDelivery }
+            : {}),
           env: paneEnv,
           title,
           tabId: tab.id,
@@ -195,7 +183,10 @@ export async function launchAgentBackgroundSession(
         cols: 120,
         rows: 40,
         cwd: worktree.path,
-        ...(sshConnectionId ? {} : { command: startupPlan.launchCommand }),
+        command: startupPlan.launchCommand,
+        ...(!startupPlan.startupCommandDelivery
+          ? {}
+          : { startupCommandDelivery: startupPlan.startupCommandDelivery }),
         env: paneEnv,
         connectionId: sshConnectionId,
         worktreeId,
@@ -234,14 +225,15 @@ export async function launchAgentBackgroundSession(
     exitHandled = true
     unsubscribeExit()
     unsubscribeData()
-    clearSshStartupInjectTimer()
+    sshStartupDelivery.clear()
     useAppStore.getState().clearTabPtyId(tab.id, ptyId)
     onExit?.(ptyId, code)
   }
   const processAgentStatus = createAgentStatusOscProcessor()
   const handleData = (data: string): void => {
+    data = sshStartupDelivery.handleData(data)
     onData?.(data)
-    scheduleSshStartupInjection(ptyId)
+    sshStartupDelivery.schedule(ptyId)
     const processed = processAgentStatus(data)
     for (const payload of processed.payloads) {
       useAppStore.getState().setAgentStatus(paneKey, payload, undefined)
diff --git a/src/renderer/src/lib/launch-agent-in-new-tab.ts b/src/renderer/src/lib/launch-agent-in-new-tab.ts
index b9e752c97..df11c678f 100644
--- a/src/renderer/src/lib/launch-agent-in-new-tab.ts
+++ b/src/renderer/src/lib/launch-agent-in-new-tab.ts
@@ -3,7 +3,6 @@ import { useAppStore } from '@/store'
 import {
   buildAgentDraftLaunchPlan,
   buildAgentStartupPlan,
-  type AgentDraftLaunchPlan,
   type AgentStartupPlan
 } from '@/lib/tui-agent-startup'
 import { CLIENT_PLATFORM } from '@/lib/new-workspace'
@@ -28,8 +27,6 @@ import type { TuiAgent } from '../../../shared/types'
 import type { LaunchSource } from '../../../shared/telemetry-events'
 import { translate } from '@/i18n/i18n'
 
-const WIN32_INLINE_DRAFT_LIMIT_CHARS = 24_000
-
 export type LaunchAgentInNewTabArgs = {
   agent: TuiAgent
   worktreeId: string
@@ -88,23 +85,6 @@ function seedCommandCodeSubmittedPromptStatus(tabId: string, prompt: string): vo
   }
 }
 
-function canUseInlineDraftLaunchPlan(
-  plan: AgentDraftLaunchPlan,
-  platform: NodeJS.Platform
-): boolean {
-  if (platform !== 'win32') {
-    return true
-  }
-  const envChars = Object.entries(plan.env ?? {}).reduce(
-    (total, [key, value]) => total + key.length + value.length,
-    0
-  )
-  // Why: Windows CreateProcess/env blocks have tight length ceilings. Large
-  // generated drafts should use the existing post-ready paste path instead of
-  // failing the PTY spawn before the agent starts.
-  return plan.launchCommand.length + envChars <= WIN32_INLINE_DRAFT_LIMIT_CHARS
-}
-
 /**
  * Create a new terminal tab and queue the agent's launch command, optionally
  * with an initial prompt.
@@ -195,12 +175,15 @@ export function launchAgentInNewTab(args: LaunchAgentInNewTabArgs): LaunchAgentI
       agentArgs: effectiveAgentArgs,
       agentEnv
     })
-    if (draftLaunchPlan && canUseInlineDraftLaunchPlan(draftLaunchPlan, resolvedLaunchPlatform)) {
+    if (draftLaunchPlan) {
       startupPlan = {
         agent: draftLaunchPlan.agent,
         launchCommand: draftLaunchPlan.launchCommand,
         expectedProcess: draftLaunchPlan.expectedProcess,
         followupPrompt: null,
+        ...(draftLaunchPlan.startupCommandDelivery
+          ? { startupCommandDelivery: draftLaunchPlan.startupCommandDelivery }
+          : {}),
         ...(draftLaunchPlan.env ? { env: draftLaunchPlan.env } : {})
       }
     } else {
@@ -253,7 +236,14 @@ export function launchAgentInNewTab(args: LaunchAgentInNewTabArgs): LaunchAgentI
       environmentId: runtimeEnvironmentId,
       targetGroupId: groupId,
       activate: true,
-      ...(hasPrompt ? { command: startupPlan.launchCommand } : { agent })
+      ...(hasPrompt
+        ? {
+            command: startupPlan.launchCommand,
+            ...(startupPlan.startupCommandDelivery
+              ? { startupCommandDelivery: startupPlan.startupCommandDelivery }
+              : {})
+          }
+        : { agent })
     }).then((created) => {
       // Why: created means the host accepted the launch, not that a local tab
       // exists; keep pruning stale local rows until the snapshot mirrors.
@@ -296,6 +286,9 @@ export function launchAgentInNewTab(args: LaunchAgentInNewTabArgs): LaunchAgentI
   store.queueTabStartupCommand(tab.id, {
     command: startupPlan.launchCommand,
     ...(startupPlan.env ? { env: startupPlan.env } : {}),
+    ...(startupPlan.startupCommandDelivery
+      ? { startupCommandDelivery: startupPlan.startupCommandDelivery }
+      : {}),
     ...(agent === 'command-code' && hasPrompt && promptDelivery === 'auto-submit'
       ? { initialAgentStatus: { agent, prompt: trimmedPrompt } }
       : {}),
diff --git a/src/renderer/src/lib/launch-work-item-direct-agent.test.ts b/src/renderer/src/lib/launch-work-item-direct-agent.test.ts
new file mode 100644
index 000000000..3422f078b
--- /dev/null
+++ b/src/renderer/src/lib/launch-work-item-direct-agent.test.ts
@@ -0,0 +1,36 @@
+import { describe, expect, it, vi } from 'vitest'
+
+vi.mock('sonner', () => ({ toast: { message: vi.fn() } }))
+vi.mock('@/lib/agent-paste-draft', () => ({ pasteDraftWhenAgentReady: vi.fn() }))
+vi.mock('@/lib/telemetry', () => ({
+  track: vi.fn(),
+  tuiAgentToAgentKind: (agent: string) => agent
+}))
+vi.mock('@/i18n/i18n', () => ({ translate: (_key: string, value: string) => value }))
+
+import { buildDirectWorkItemStartupOpts } from './launch-work-item-direct-agent'
+import type { AgentStartupPlan } from './tui-agent-startup'
+
+describe('buildDirectWorkItemStartupOpts', () => {
+  it('preserves Codex startup command delivery for linked work-item launches', () => {
+    const plan: AgentStartupPlan = {
+      agent: 'codex',
+      launchCommand: "codex 'review linked issue'",
+      expectedProcess: 'codex',
+      followupPrompt: null,
+      startupCommandDelivery: 'shell-ready'
+    }
+
+    expect(buildDirectWorkItemStartupOpts('codex', plan, 'task_page')).toEqual({
+      startup: {
+        command: "codex 'review linked issue'",
+        startupCommandDelivery: 'shell-ready',
+        telemetry: {
+          agent_kind: 'codex',
+          launch_source: 'task_page',
+          request_kind: 'new'
+        }
+      }
+    })
+  })
+})
diff --git a/src/renderer/src/lib/launch-work-item-direct-agent.ts b/src/renderer/src/lib/launch-work-item-direct-agent.ts
index 065c093e9..2260e747b 100644
--- a/src/renderer/src/lib/launch-work-item-direct-agent.ts
+++ b/src/renderer/src/lib/launch-work-item-direct-agent.ts
@@ -4,6 +4,7 @@ import { track, tuiAgentToAgentKind } from '@/lib/telemetry'
 import type { AgentStartupPlan } from '@/lib/tui-agent-startup'
 import type { AgentStartedTelemetry } from '@/lib/worktree-activation'
 import type { LaunchSource } from '../../../shared/telemetry-events'
+import type { StartupCommandDelivery } from '../../../shared/codex-startup-delivery'
 import type { TuiAgent } from '../../../shared/types'
 import { translate } from '@/i18n/i18n'
 
@@ -12,7 +13,12 @@ export function buildDirectWorkItemStartupOpts(
   plan: AgentStartupPlan | null,
   launchSource: LaunchSource
 ): {
-  startup?: { command: string; env?: Record<string, string>; telemetry?: AgentStartedTelemetry }
+  startup?: {
+    command: string
+    env?: Record<string, string>
+    startupCommandDelivery?: StartupCommandDelivery
+    telemetry?: AgentStartedTelemetry
+  }
 } {
   if (!plan) {
     return {}
@@ -25,6 +31,9 @@ export function buildDirectWorkItemStartupOpts(
     startup: {
       command: plan.launchCommand,
       ...(plan.env ? { env: plan.env } : {}),
+      ...(plan.startupCommandDelivery
+        ? { startupCommandDelivery: plan.startupCommandDelivery }
+        : {}),
       ...(telemetry ? { telemetry } : {})
     }
   }
diff --git a/src/renderer/src/lib/launch-work-item-direct.ts b/src/renderer/src/lib/launch-work-item-direct.ts
index 1574ae19c..796bf3266 100644
--- a/src/renderer/src/lib/launch-work-item-direct.ts
+++ b/src/renderer/src/lib/launch-work-item-direct.ts
@@ -297,6 +297,9 @@ export async function launchWorkItemDirect(args: LaunchWorkItemDirectArgs): Prom
         launchCommand: draftLaunchPlan.launchCommand,
         expectedProcess: draftLaunchPlan.expectedProcess,
         followupPrompt: null,
+        ...(draftLaunchPlan.startupCommandDelivery
+          ? { startupCommandDelivery: draftLaunchPlan.startupCommandDelivery }
+          : {}),
         ...(draftLaunchPlan.env ? { env: draftLaunchPlan.env } : {})
       }
       draftLaunchedNatively = true
diff --git a/src/renderer/src/lib/onboarding-folder-agent-startup.ts b/src/renderer/src/lib/onboarding-folder-agent-startup.ts
index 9f5fb1fe0..e551500e3 100644
--- a/src/renderer/src/lib/onboarding-folder-agent-startup.ts
+++ b/src/renderer/src/lib/onboarding-folder-agent-startup.ts
@@ -6,11 +6,13 @@ import {
   resolveTuiAgentLaunchEnv
 } from '../../../shared/tui-agent-launch-defaults'
 import type { AgentStartedTelemetry } from '@/lib/worktree-activation'
+import type { StartupCommandDelivery } from '../../../shared/codex-startup-delivery'
 import type { GlobalSettings, OnboardingState } from '../../../shared/types'
 
 export type OnboardingFolderAgentStartup = {
   command: string
   env?: Record<string, string>
+  startupCommandDelivery?: StartupCommandDelivery
   telemetry: AgentStartedTelemetry
 }
 
@@ -50,6 +52,9 @@ export function buildOnboardingFolderAgentStartup(
   return {
     command: startupPlan.launchCommand,
     ...(startupPlan.env ? { env: startupPlan.env } : {}),
+    ...(startupPlan.startupCommandDelivery
+      ? { startupCommandDelivery: startupPlan.startupCommandDelivery }
+      : {}),
     telemetry: {
       agent_kind: tuiAgentToAgentKind(agent),
       launch_source: 'onboarding',
diff --git a/src/renderer/src/lib/resume-sleeping-agent-session.ts b/src/renderer/src/lib/resume-sleeping-agent-session.ts
index 793d5650f..59d4f02e5 100644
--- a/src/renderer/src/lib/resume-sleeping-agent-session.ts
+++ b/src/renderer/src/lib/resume-sleeping-agent-session.ts
@@ -73,6 +73,9 @@ function launchSleepingAgentSession(record: SleepingAgentSessionRecord): boolean
   })
   state.queueTabStartupCommand(tab.id, {
     command: startupPlan.launchCommand,
+    ...(startupPlan.startupCommandDelivery
+      ? { startupCommandDelivery: startupPlan.startupCommandDelivery }
+      : {}),
     showSessionRestoredBanner: true,
     telemetry: {
       agent_kind: tuiAgentToAgentKind(record.agent),
diff --git a/src/renderer/src/lib/source-control-agent-action-plan.ts b/src/renderer/src/lib/source-control-agent-action-plan.ts
index ca5ac2a54..f1cf4ff0c 100644
--- a/src/renderer/src/lib/source-control-agent-action-plan.ts
+++ b/src/renderer/src/lib/source-control-agent-action-plan.ts
@@ -111,6 +111,9 @@ export function planSourceControlAgentActionLaunch(args: {
         launchCommand: draftLaunchPlan.launchCommand,
         expectedProcess: draftLaunchPlan.expectedProcess,
         followupPrompt: null,
+        ...(draftLaunchPlan.startupCommandDelivery
+          ? { startupCommandDelivery: draftLaunchPlan.startupCommandDelivery }
+          : {}),
         ...(draftLaunchPlan.env ? { env: draftLaunchPlan.env } : {})
       }
       delivery = 'draft-native'
diff --git a/src/renderer/src/lib/ssh-background-startup-delivery.ts b/src/renderer/src/lib/ssh-background-startup-delivery.ts
new file mode 100644
index 000000000..a2c8cc6f7
--- /dev/null
+++ b/src/renderer/src/lib/ssh-background-startup-delivery.ts
@@ -0,0 +1,104 @@
+import {
+  createShellReadyMarkerScanState,
+  scanForShellReadyMarker
+} from '@/components/terminal-pane/shell-ready-marker-scan'
+
+const SSH_SHELL_READY_STARTUP_FALLBACK_MS = 1500
+
+type SshBackgroundStartupDeliveryOptions = {
+  command: string | null
+  waitForShellReady: boolean
+  write: (ptyId: string, data: string) => void
+}
+
+export type SshBackgroundStartupDelivery = {
+  handleData(data: string): string
+  schedule(ptyId: string): void
+  clear(): void
+}
+
+export function createSshBackgroundStartupDelivery(
+  options: SshBackgroundStartupDeliveryOptions
+): SshBackgroundStartupDelivery {
+  let pendingCommand = options.command
+  let lastPtyId: string | null = null
+  let startupShellReady = !options.waitForShellReady
+  const markerScan = options.waitForShellReady ? createShellReadyMarkerScanState() : null
+  let injectTimer: ReturnType<typeof setTimeout> | null = null
+  let fallbackTimer: ReturnType<typeof setTimeout> | null = null
+
+  const clearInjectTimer = (): void => {
+    if (injectTimer !== null) {
+      clearTimeout(injectTimer)
+      injectTimer = null
+    }
+  }
+  const clearFallbackTimer = (): void => {
+    if (fallbackTimer !== null) {
+      clearTimeout(fallbackTimer)
+      fallbackTimer = null
+    }
+  }
+  function markShellReady(): void {
+    if (startupShellReady) {
+      return
+    }
+    startupShellReady = true
+    clearFallbackTimer()
+    if (pendingCommand && lastPtyId) {
+      schedule(lastPtyId)
+    }
+  }
+
+  const schedule = (ptyId: string): void => {
+    lastPtyId = ptyId
+    if (!pendingCommand) {
+      return
+    }
+    if (!startupShellReady) {
+      if (fallbackTimer === null) {
+        // Why: hidden SSH sessions can use shells that cannot emit Orca's
+        // marker. Prefer readiness, but never drop the startup command forever.
+        fallbackTimer = setTimeout(() => {
+          fallbackTimer = null
+          markShellReady()
+        }, SSH_SHELL_READY_STARTUP_FALLBACK_MS)
+      }
+      return
+    }
+    clearInjectTimer()
+    injectTimer = setTimeout(() => {
+      injectTimer = null
+      const command = pendingCommand
+      if (!command) {
+        return
+      }
+      pendingCommand = null
+      // Why: the SSH relay treats spawn.command as metadata for interactive
+      // PTYs; hidden automation tabs still submit the command themselves.
+      const submittedCommand =
+        command.endsWith('\r') || command.endsWith('\n') ? command : `${command}\r`
+      options.write(ptyId, submittedCommand)
+    }, 50)
+  }
+
+  return {
+    handleData(data) {
+      if (!markerScan) {
+        return data
+      }
+      const scanned = scanForShellReadyMarker(markerScan, data)
+      if (scanned.matched) {
+        markShellReady()
+      }
+      return scanned.output
+    },
+    schedule,
+    clear() {
+      clearInjectTimer()
+      clearFallbackTimer()
+      pendingCommand = null
+      lastPtyId = null
+    }
+  }
+}
diff --git a/src/renderer/src/lib/worktree-activation.ts b/src/renderer/src/lib/worktree-activation.ts
index a82cb3a5e..2957c43d5 100644
--- a/src/renderer/src/lib/worktree-activation.ts
+++ b/src/renderer/src/lib/worktree-activation.ts
@@ -8,6 +8,7 @@ import type {
   WorktreeSetupLaunch
 } from '../../../shared/types'
 import type { EventProps } from '../../../shared/telemetry-events'
+import type { StartupCommandDelivery } from '../../../shared/codex-startup-delivery'
 import { shouldAutoCreateInitialTerminal } from '@/components/terminal/initial-terminal'
 import { buildSetupRunnerCommand } from './setup-runner'
 import { buildAgentStartupPlan } from './tui-agent-startup'
@@ -61,6 +62,7 @@ export type AgentStartedTelemetry = EventProps<'agent_started'>
 export type WorktreeStartupPayload = {
   command: string
   env?: Record<string, string>
+  startupCommandDelivery?: StartupCommandDelivery
   initialAgentStatus?: { agent: TuiAgent; prompt: string }
   telemetry?: AgentStartedTelemetry
 }
@@ -240,6 +242,9 @@ function buildCreatedAgentReopenStartup(worktree: Worktree): WorktreeStartupPayl
   return {
     command: startupPlan.launchCommand,
     ...(startupPlan.env ? { env: startupPlan.env } : {}),
+    ...(startupPlan.startupCommandDelivery
+      ? { startupCommandDelivery: startupPlan.startupCommandDelivery }
+      : {}),
     telemetry: {
       agent_kind: tuiAgentToAgentKind(agent),
       launch_source: 'sidebar',
diff --git a/src/renderer/src/lib/worktree-creation-flow.ts b/src/renderer/src/lib/worktree-creation-flow.ts
index f3da917d9..9c3fe6273 100644
--- a/src/renderer/src/lib/worktree-creation-flow.ts
+++ b/src/renderer/src/lib/worktree-creation-flow.ts
@@ -31,6 +31,7 @@ function buildStartupOpt(
   return {
     command: plan.launchCommand,
     ...(plan.env ? { env: plan.env } : {}),
+    ...(plan.startupCommandDelivery ? { startupCommandDelivery: plan.startupCommandDelivery } : {}),
     // Why: command-code shows its prompt in the tab status before the first
     // hook fires, so the prompt is threaded through here.
     ...(request.agent === 'command-code' && request.quickPrompt.trim().length > 0
diff --git a/src/renderer/src/runtime/web-runtime-session.test.ts b/src/renderer/src/runtime/web-runtime-session.test.ts
index 7401ec55c..2524f8fd0 100644
--- a/src/renderer/src/runtime/web-runtime-session.test.ts
+++ b/src/renderer/src/runtime/web-runtime-session.test.ts
@@ -420,7 +420,8 @@ describe('createWebRuntimeSessionTerminal', () => {
         worktreeId: WORKTREE_ID,
         afterTabId: 'web-terminal-host-tab-1%3A%3Aleaf-1',
         targetGroupId: 'group-left',
-        command: 'zsh',
+        command: "codex 'linked issue context'",
+        startupCommandDelivery: 'shell-ready',
         activate: true
       })
     ).resolves.toBe(true)
@@ -432,7 +433,8 @@ describe('createWebRuntimeSessionTerminal', () => {
         worktree: `id:${WORKTREE_ID}`,
         afterTabId: 'host-tab-1::leaf-1',
         targetGroupId: 'group-left',
-        command: 'zsh',
+        command: "codex 'linked issue context'",
+        startupCommandDelivery: 'shell-ready',
         activate: true
       },
       timeoutMs: 15_000
diff --git a/src/renderer/src/runtime/web-runtime-session.ts b/src/renderer/src/runtime/web-runtime-session.ts
index 9dab68eea..9fb542226 100644
--- a/src/renderer/src/runtime/web-runtime-session.ts
+++ b/src/renderer/src/runtime/web-runtime-session.ts
@@ -10,6 +10,7 @@ import type {
   RuntimeTerminalSplit
 } from '../../../shared/runtime-types'
 import type { TerminalPaneSplitSource } from '../../../shared/feature-education-telemetry'
+import type { StartupCommandDelivery } from '../../../shared/codex-startup-delivery'
 import type { TuiAgent } from '../../../shared/types'
 import type { AppState } from '../store/types'
 import { useAppStore } from '../store'
@@ -44,6 +45,7 @@ export async function createWebRuntimeSessionTerminal(args: {
   afterTabId?: string
   targetGroupId?: string
   command?: string
+  startupCommandDelivery?: StartupCommandDelivery
   agent?: TuiAgent
   activate?: boolean
   selectWorktree?: boolean
@@ -68,6 +70,7 @@ export async function createWebRuntimeSessionTerminal(args: {
         afterTabId: args.afterTabId ? toHostSessionTabId(args.afterTabId) : undefined,
         targetGroupId: args.targetGroupId,
         command: args.command,
+        startupCommandDelivery: args.startupCommandDelivery,
         agent: args.agent,
         activate: args.activate !== false
       },
diff --git a/src/renderer/src/store/slices/terminals.ts b/src/renderer/src/store/slices/terminals.ts
index 7afb004e4..ff3a76dc2 100644
--- a/src/renderer/src/store/slices/terminals.ts
+++ b/src/renderer/src/store/slices/terminals.ts
@@ -23,6 +23,7 @@ import { isValidHostTerminalTabId, isValidTerminalTabId } from '../../../../shar
 import { getRepoIdFromWorktreeId, splitWorktreeId } from '../../../../shared/worktree-id'
 import { isWslUncPath } from '../../../../shared/wsl-paths'
 import type { ProjectExecutionRuntimeResolution } from '../../../../shared/project-execution-runtime'
+import type { StartupCommandDelivery } from '../../../../shared/codex-startup-delivery'
 import { resolveLocalWindowsTerminalShellOverrideForTab } from '../../../../shared/local-windows-terminal-runtime'
 import type { AgentStartedTelemetry } from '../../lib/worktree-activation'
 import { scheduleRuntimeGraphSync } from '@/runtime/sync-runtime-graph'
@@ -308,6 +309,7 @@ export type TerminalSlice = {
       /** Renderer-delivered startup input for callers that need xterm paste
        *  semantics before the submit Enter. */
       delivery?: 'terminal-paste'
+      startupCommandDelivery?: StartupCommandDelivery
       env?: Record<string, string>
       /** Initial prompt-start status for agents that lack native prompt hooks. */
       initialAgentStatus?: { agent: TuiAgent; prompt: string }
@@ -449,6 +451,7 @@ export type TerminalSlice = {
     startup: {
       command: string
       delivery?: 'terminal-paste'
+      startupCommandDelivery?: StartupCommandDelivery
       env?: Record<string, string>
       initialAgentStatus?: { agent: TuiAgent; prompt: string }
       showSessionRestoredBanner?: boolean
@@ -458,6 +461,7 @@ export type TerminalSlice = {
   consumeTabStartupCommand: (tabId: string) => {
     command: string
     delivery?: 'terminal-paste'
+    startupCommandDelivery?: StartupCommandDelivery
     env?: Record<string, string>
     initialAgentStatus?: { agent: TuiAgent; prompt: string }
     showSessionRestoredBanner?: boolean
diff --git a/src/renderer/src/store/slices/worktrees.ts b/src/renderer/src/store/slices/worktrees.ts
index c7fc1be86..c4faadc87 100644
--- a/src/renderer/src/store/slices/worktrees.ts
+++ b/src/renderer/src/store/slices/worktrees.ts
@@ -1691,6 +1691,9 @@ export const createWorktreeSlice: StateCreator<AppState, [], [], WorktreeSlice>
                       ? {
                           startupCommand: startup.command,
                           ...(startup.env ? { startupEnv: startup.env } : {}),
+                          ...(startup.startupCommandDelivery
+                            ? { startupCommandDelivery: startup.startupCommandDelivery }
+                            : {}),
                           activate: true
                         }
                       : {})
diff --git a/src/shared/codex-startup-delivery.test.ts b/src/shared/codex-startup-delivery.test.ts
new file mode 100644
index 000000000..e7788f778
--- /dev/null
+++ b/src/shared/codex-startup-delivery.test.ts
@@ -0,0 +1,28 @@
+import { describe, expect, it } from 'vitest'
+import { hasCodexNativeDraftFlag } from './codex-startup-delivery'
+
+describe('hasCodexNativeDraftFlag', () => {
+  it('matches Codex --prefill option tokens', () => {
+    expect(hasCodexNativeDraftFlag("codex --prefill 'linked issue context'")).toBe(true)
+    expect(hasCodexNativeDraftFlag("codex --model gpt-5 --prefill 'draft'")).toBe(true)
+  })
+
+  it('matches Codex --prefill=value option tokens', () => {
+    expect(hasCodexNativeDraftFlag('codex --prefill=review')).toBe(true)
+    expect(hasCodexNativeDraftFlag("codex --prefill='linked issue context'")).toBe(true)
+  })
+
+  it('does not match quoted prompt text mentioning prefill', () => {
+    expect(hasCodexNativeDraftFlag("codex 'please compare --prefill behavior'")).toBe(false)
+    expect(hasCodexNativeDraftFlag("codex '--prefill=not-an-option'")).toBe(false)
+  })
+
+  it('does not match non-Codex commands', () => {
+    expect(hasCodexNativeDraftFlag("claude --prefill 'review this'")).toBe(false)
+  })
+
+  it('leaves plain Codex and normal Codex arguments on the fast path', () => {
+    expect(hasCodexNativeDraftFlag('codex')).toBe(false)
+    expect(hasCodexNativeDraftFlag('codex --model gpt-5')).toBe(false)
+  })
+})
diff --git a/src/shared/codex-startup-delivery.ts b/src/shared/codex-startup-delivery.ts
new file mode 100644
index 000000000..a45337dd0
--- /dev/null
+++ b/src/shared/codex-startup-delivery.ts
@@ -0,0 +1,82 @@
+import { recognizeAgentProcessFromCommandLine } from './agent-process-recognition'
+
+export type StartupCommandDelivery = 'fast' | 'shell-ready'
+
+type CommandToken = {
+  value: string
+  startsQuoted: boolean
+}
+
+function tokenizeCommandWithQuoteMetadata(command: string): CommandToken[] {
+  const tokens: CommandToken[] = []
+  let current = ''
+  let inToken = false
+  let startsQuoted = false
+  let quote: '"' | "'" | null = null
+  let escaped = false
+
+  for (let index = 0; index < command.length; index += 1) {
+    const char = command[index]
+    if (escaped) {
+      current += char
+      escaped = false
+      continue
+    }
+    if (char === '\\' && quote !== "'") {
+      const next = command[index + 1]
+      if (next && (/\s/.test(next) || next === '"' || next === "'" || next === '\\')) {
+        escaped = true
+        inToken = true
+        continue
+      }
+    }
+    if ((char === '"' || char === "'") && quote === null) {
+      if (!inToken) {
+        startsQuoted = true
+      }
+      quote = char
+      inToken = true
+      continue
+    }
+    if (quote === char) {
+      quote = null
+      continue
+    }
+    if (/\s/.test(char) && quote === null) {
+      if (inToken) {
+        tokens.push({ value: current, startsQuoted })
+        current = ''
+        inToken = false
+        startsQuoted = false
+      }
+      continue
+    }
+    current += char
+    inToken = true
+  }
+
+  if (inToken) {
+    tokens.push({ value: current, startsQuoted })
+  }
+  return tokens
+}
+
+export function hasCodexNativeDraftFlag(command: string | null | undefined): boolean {
+  if (recognizeAgentProcessFromCommandLine(command)?.agent !== 'codex' || !command) {
+    return false
+  }
+  const tokens = tokenizeCommandWithQuoteMetadata(command)
+  return tokens.some(
+    (token, index) =>
+      index > 0 &&
+      !token.startsQuoted &&
+      (token.value === '--prefill' || token.value.startsWith('--prefill='))
+  )
+}
+
+export function shouldUseShellReadyStartupDelivery(args: {
+  command: string | null | undefined
+  startupCommandDelivery?: StartupCommandDelivery
+}): boolean {
+  return args.startupCommandDelivery === 'shell-ready' || hasCodexNativeDraftFlag(args.command)
+}
diff --git a/src/shared/tui-agent-startup.test.ts b/src/shared/tui-agent-startup.test.ts
index 9ce0cd839..7ef17bfcf 100644
--- a/src/shared/tui-agent-startup.test.ts
+++ b/src/shared/tui-agent-startup.test.ts
@@ -57,6 +57,24 @@ describe('tui agent startup plans', () => {
     })
 
     expect(plan?.launchCommand).toBe("codex 'fix it'")
+    expect(plan?.startupCommandDelivery).toBe('shell-ready')
+  })
+
+  it('keeps plain empty Codex startup on the fast delivery path', () => {
+    const plan = buildAgentStartupPlan({
+      agent: 'codex',
+      prompt: '',
+      cmdOverrides: {},
+      platform: 'linux',
+      allowEmptyPromptLaunch: true
+    })
+
+    expect(plan).toEqual({
+      agent: 'codex',
+      launchCommand: 'codex',
+      expectedProcess: 'codex',
+      followupPrompt: null
+    })
   })
 
   it('launches Claude without Orca settings injection', () => {
@@ -266,6 +284,28 @@ describe('tui agent startup plans', () => {
     expect(plan?.launchCommand).toBe('omp; unset ORCA_OMP_PREFILL')
   })
 
+  it('returns null for oversized Windows flag drafts so callers paste after ready', () => {
+    expect(
+      buildAgentDraftLaunchPlan({
+        agent: 'claude',
+        draft: 'x'.repeat(25_000),
+        cmdOverrides: {},
+        platform: 'win32'
+      })
+    ).toBeNull()
+  })
+
+  it('returns null for oversized Windows env-var drafts so callers paste after ready', () => {
+    expect(
+      buildAgentDraftLaunchPlan({
+        agent: 'pi',
+        draft: 'x'.repeat(25_000),
+        cmdOverrides: {},
+        platform: 'win32'
+      })
+    ).toBeNull()
+  })
+
   it('launches Devin with stdin-after-start prompt delivery', () => {
     const plan = buildAgentStartupPlan({
       agent: 'devin',
diff --git a/src/shared/tui-agent-startup.ts b/src/shared/tui-agent-startup.ts
index f8a8c520e..026134e7e 100644
--- a/src/shared/tui-agent-startup.ts
+++ b/src/shared/tui-agent-startup.ts
@@ -6,8 +6,11 @@ import {
 } from './agent-session-resume'
 import { tokenizeCustomCommandTemplate } from './commit-message-prompt'
 import { TUI_AGENT_CONFIG } from './tui-agent-config'
+import type { StartupCommandDelivery } from './codex-startup-delivery'
 import type { TuiAgent } from './types'
 
+const WIN32_INLINE_DRAFT_LIMIT_CHARS = 24_000
+
 export type AgentStartupPlan = {
   agent: TuiAgent
   launchCommand: string
@@ -15,6 +18,7 @@ export type AgentStartupPlan = {
   followupPrompt: string | null
   draftPrompt?: string | null
   env?: Record<string, string>
+  startupCommandDelivery?: StartupCommandDelivery
 }
 
 export type AgentStartupShell = 'posix' | 'powershell' | 'cmd'
@@ -143,6 +147,7 @@ export function buildAgentStartupPlan(args: {
       launchCommand: `${baseCommand.command} ${quotedPrompt}`,
       expectedProcess: config.expectedProcess,
       followupPrompt: null,
+      ...(agent === 'codex' ? { startupCommandDelivery: 'shell-ready' as const } : {}),
       ...(args.agentEnv ? { env: { ...args.agentEnv } } : {})
     }
   }
@@ -229,6 +234,23 @@ export type AgentDraftLaunchPlan = {
   launchCommand: string
   expectedProcess: string
   env?: Record<string, string>
+  startupCommandDelivery?: StartupCommandDelivery
+}
+
+function inlineDraftPlanFitsPlatform(
+  plan: AgentDraftLaunchPlan,
+  platform: NodeJS.Platform
+): boolean {
+  if (platform !== 'win32') {
+    return true
+  }
+  const envChars = Object.entries(plan.env ?? {}).reduce(
+    (total, [key, value]) => total + key.length + value.length,
+    0
+  )
+  // Why: Windows CreateProcess/env blocks have tight length ceilings. Large
+  // generated drafts should use the existing post-ready paste fallback.
+  return plan.launchCommand.length + envChars <= WIN32_INLINE_DRAFT_LIMIT_CHARS
 }
 
 export function buildAgentDraftLaunchPlan(args: {
@@ -256,25 +278,30 @@ export function buildAgentDraftLaunchPlan(args: {
   if (!baseCommand.ok) {
     return null
   }
+  let plan: AgentDraftLaunchPlan | null = null
   if (config.draftPromptFlag) {
     const quoted = quoteStartupArg(trimmed, shell)
-    return {
+    plan = {
       agent,
       launchCommand: `${baseCommand.command} ${config.draftPromptFlag} ${quoted}`,
       expectedProcess: config.expectedProcess,
+      // Why: native draft flags carry user text on argv and must survive rc-file startup.
+      ...(agent === 'codex' ? { startupCommandDelivery: 'shell-ready' as const } : {}),
       ...(args.agentEnv ? { env: { ...args.agentEnv } } : {})
     }
-  }
-  if (config.draftPromptEnvVar) {
+  } else if (config.draftPromptEnvVar) {
     const clearVar = clearEnvCommand(config.draftPromptEnvVar, shell)
-    return {
+    plan = {
       agent,
       launchCommand: `${baseCommand.command}${commandSeparator(shell)}${clearVar}`,
       expectedProcess: config.expectedProcess,
       env: { ...args.agentEnv, [config.draftPromptEnvVar]: trimmed }
     }
   }
-  return null
+  if (!plan || !inlineDraftPlanFitsPlatform(plan, platform)) {
+    return null
+  }
+  return plan
 }
 
 export { isShellProcess }
diff --git a/src/shared/types.ts b/src/shared/types.ts
index 29b6ddb0f..81f977637 100644
--- a/src/shared/types.ts
+++ b/src/shared/types.ts
@@ -28,6 +28,7 @@ import type {
   RepoSourceControlAiOverrides,
   SourceControlAiSettings
 } from './source-control-ai-types'
+import type { StartupCommandDelivery } from './codex-startup-delivery'
 import type { AgentKind, LaunchSource, RequestKind } from './telemetry-events'
 import type { SleepingAgentSessionRecord } from './agent-session-resume'
 import type { ClaudeAgentTeamsMode } from './claude-agent-teams-tmux-compat'
@@ -1865,6 +1866,7 @@ export type WorktreeSetupLaunch = {
 export type WorktreeStartupLaunch = {
   command: string
   env?: Record<string, string>
+  startupCommandDelivery?: StartupCommandDelivery
   telemetry?: { agent_kind: AgentKind; launch_source: LaunchSource; request_kind: RequestKind }
 }