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1# Hooks1# Hooks

2 2

~~3Experimental. Hooks are under active development. Windows support temporarily~~

~~4disabled.~~

6Hooks are an extensibility framework for Codex. They allow3Hooks are an extensibility framework for Codex. They allow

7you to inject your own scripts into the agentic loop, enabling features such as:4you to inject your own scripts into the agentic loop, enabling features such as:

8 5

9- Send the conversation to a custom logging/analytics engine6- Send the conversation to a custom logging/analytics engine

10- Scan your team's prompts to block accidentally pasting API keys7- Scan your team's prompts to block accidentally pasting API keys

11- Summarize conversations to create persistent memories automatically8- Summarize conversations to create persistent memories automatically

~~12- Run a custom validator when a conversation turn stops, enforcing standards~~9- Run a custom validation check when a conversation turn stops, enforcing standards

13- Customize prompting when in a certain directory10- Customize prompting when in a certain directory

14 11

15Hooks are behind a feature flag in `config.toml`:12Hooks are behind a feature flag in `config.toml`:

24- Matching hooks from multiple files all run.21- Matching hooks from multiple files all run.

25- Multiple matching command hooks for the same event are launched concurrently,22- Multiple matching command hooks for the same event are launched concurrently,

26 so one hook cannot prevent another matching hook from starting.23 so one hook cannot prevent another matching hook from starting.

~~27- `PreToolUse`, `PostToolUse`, `UserPromptSubmit`, and `Stop` run at turn~~24- `PreToolUse`, `PermissionRequest`, `PostToolUse`, `UserPromptSubmit`, and

~~28 scope.~~25 `Stop` run at turn scope.

~~29- Hooks are currently disabled on Windows.~~

30 26

31## Where Codex looks for hooks27## Where Codex looks for hooks

32 28

~~33Codex discovers `hooks.json` next to active config layers.~~29Codex discovers hooks next to active config layers in either of these forms:

31- `hooks.json`

32- inline `[hooks]` tables inside `config.toml`

34Installed plugins can also bundle lifecycle config through their plugin

35manifest or a default `hooks/hooks.json` file. See [Build

36plugins](https://developers.openai.com/codex/plugins/build#bundled-mcp-servers-and-lifecycle-config) for the

37plugin packaging rules.

34 38

~~35In practice, the two most useful locations are:~~39In practice, the four most useful locations are:

36 40

37- `~/.codex/hooks.json`41- `~/.codex/hooks.json`

42- `~/.codex/config.toml`

38- `<repo>/.codex/hooks.json`43- `<repo>/.codex/hooks.json`

44- `<repo>/.codex/config.toml`

39 45

~~40If more than one `hooks.json` file exists, Codex loads all matching hooks.~~46If more than one hook source exists, Codex loads all matching hooks.

41Higher-precedence config layers do not replace lower-precedence hooks.47Higher-precedence config layers do not replace lower-precedence hooks.

48If a single layer contains both `hooks.json` and inline `[hooks]`, Codex

49merges them and warns at startup. Prefer one representation per layer.

51Project-local hooks load only when the project `.codex/` layer is trusted. In

52untrusted projects, Codex still loads user and system hooks from their own

53active config layers.

42 54

43## Config shape55## Config shape

44 56

75 ]87 ]

76 }88 }

77 ],89 ],

90 "PermissionRequest": [

91 {

92 "matcher": "Bash",

93 "hooks": [

94 {

95 "type": "command",

96 "command": "/usr/bin/python3 \"$(git rev-parse --show-toplevel)/.codex/hooks/permission_request.py\"",

97 "statusMessage": "Checking approval request"

98 }

99 ]

100 }

101 ],

78 "PostToolUse": [102 "PostToolUse": [

79 {103 {

80 "matcher": "Bash",104 "matcher": "Bash",

115Notes:139Notes:

116 140

117- `timeout` is in seconds.141- `timeout` is in seconds.

118- `timeoutSec` is also accepted as an alias.

119- If `timeout` is omitted, Codex uses `600` seconds.142- If `timeout` is omitted, Codex uses `600` seconds.

120- `statusMessage` is optional.143- `statusMessage` is optional.

121- Commands run with the session `cwd` as their working directory.144- Commands run with the session `cwd` as their working directory.

123 relative path such as `.codex/hooks/...`. Codex may be started from a146 relative path such as `.codex/hooks/...`. Codex may be started from a

124 subdirectory, and a git-root-based path keeps the hook location stable.147 subdirectory, and a git-root-based path keeps the hook location stable.

125 148

149Equivalent inline TOML in `config.toml`:

150

151```toml

152[features]

153codex_hooks = true

154

155[[hooks.PreToolUse]]

156matcher = "^Bash$"

157

158[[hooks.PreToolUse.hooks]]

159type = "command"

160command = '/usr/bin/python3 "$(git rev-parse --show-toplevel)/.codex/hooks/pre_tool_use_policy.py"'

161timeout = 30

162statusMessage = "Checking Bash command"

163

164[[hooks.PostToolUse]]

165matcher = "^Bash$"

166

167[[hooks.PostToolUse.hooks]]

168type = "command"

169command = '/usr/bin/python3 "$(git rev-parse --show-toplevel)/.codex/hooks/post_tool_use_review.py"'

170timeout = 30

171statusMessage = "Reviewing Bash output"

172```

173

174## Managed hooks from `requirements.toml`

175

176Enterprise-managed requirements can also define hooks inline under `[hooks]`.

177This is useful when admins want to enforce the hook configuration while

178delivering the actual scripts through MDM or another device-management system.

179

180```toml

181[features]

182codex_hooks = true

183

184[hooks]

185managed_dir = "/enterprise/hooks"

186windows_managed_dir = 'C:\enterprise\hooks'

187

188[[hooks.PreToolUse]]

189matcher = "^Bash$"

190

191[[hooks.PreToolUse.hooks]]

192type = "command"

193command = "python3 /enterprise/hooks/pre_tool_use_policy.py"

194timeout = 30

195statusMessage = "Checking managed Bash command"

196```

197

198Notes for managed hooks:

199

200- `managed_dir` is used on macOS and Linux.

201- `windows_managed_dir` is used on Windows.

202- Codex does not distribute the scripts in `managed_dir`; your enterprise

203 tooling must install and update them separately.

204- Managed hook commands should use absolute script paths under the configured

205 managed directory.

206

126## Matcher patterns207## Matcher patterns

127 208

128The `matcher` field is a regex string that filters when hooks fire. Use `"*"`,209The `matcher` field is a regex string that filters when hooks fire. Use `"*"`,

132Only some current Codex events honor `matcher`:213Only some current Codex events honor `matcher`:

133 214

135| --- | --- | --- |216| ------------------- | ---------------------- | ------------------------------------------------------------ |

222| `Stop` | not supported | Any configured `matcher` is ignored for this event |

223

224\*For `apply_patch`, matchers can also use `Edit` or `Write`.

141 225

142Examples:226Examples:

143 227

144- `Bash`228- `Bash`

145- `startup|resume`229- `^apply_patch$`

146- `Edit|Write`230- `Edit|Write`

~~147~~ 231- `mcp__filesystem__read_file`

148That last example is still a valid regex, but current Codex `PreToolUse` and232- `mcp__filesystem__.*`

149`PostToolUse` events only emit `Bash`, so it will not match anything today.233- `startup|resume|clear`

150 234

151## Common input fields235## Common input fields

152 236

155These are the shared fields you will usually use:239These are the shared fields you will usually use:

156 240

158| --- | --- | --- |242| ----------------- | ---------------- | ------------------------------------------- |

161| `cwd` | `string` | Working directory for the session |245| `cwd` | `string` | Working directory for the session |

189 273

190Exit `0` with no output is treated as success and Codex continues.274Exit `0` with no output is treated as success and Codex continues.

191 275

192`PreToolUse` supports `systemMessage`, but `continue`, `stopReason`, and276`PreToolUse` and `PermissionRequest` support `systemMessage`, but `continue`,

193`suppressOutput` are not currently supported for that event.277`stopReason`, and `suppressOutput` aren't currently supported for those events.

194 278

195`PostToolUse` supports `systemMessage`, `continue: false`, and `stopReason`.279`PostToolUse` supports `systemMessage`, `continue: false`, and `stopReason`.

196`suppressOutput` is parsed but not currently supported for that event.280`suppressOutput` is parsed but not currently supported for that event.

204Fields in addition to [Common input fields](#common-input-fields):288Fields in addition to [Common input fields](#common-input-fields):

205 289

207| --- | --- | --- |291| -------- | -------- | ---------------------------------------------- |

209 293

210Plain text on `stdout` is added as extra developer context.294Plain text on `stdout` is added as extra developer context.

225 309

226### PreToolUse310### PreToolUse

227 311

228Currently `PreToolUse` only supports Bash tool interception. The model can312`PreToolUse` can intercept Bash, file edits performed through `apply_patch`,

229still work around this by writing its own script to disk and then running that313and MCP tool calls. It is still a guardrail rather than a complete enforcement

230script with Bash, so treat this as a useful guardrail rather than a complete314boundary because Codex can often perform equivalent work through another

231enforcement boundary.315supported tool path.

316

317This doesn't intercept all shell calls yet, only the simple ones. The newer

318 `unified_exec` mechanism allows richer streaming stdin/stdout handling of

319 shell, but interception is incomplete. Similarly, this doesn't intercept

320 `WebSearch` or other non-shell, non-MCP tool calls.

232 321

233`matcher` is applied to `tool_name`, which currently always equals `Bash`.322`matcher` is applied to `tool_name` and matcher aliases. For file edits through

323`apply_patch`, matchers can use `apply_patch`, `Edit`, or `Write`; hook input

324still reports `tool_name: "apply_patch"`.

234 325

235Fields in addition to [Common input fields](#common-input-fields):326Fields in addition to [Common input fields](#common-input-fields):

236 327

238| --- | --- | --- |329| ------------- | ------------ | --------------------------------------------------------------------------------------------------------- |

243 334

244Plain text on `stdout` is ignored.335Plain text on `stdout` is ignored.

245 336

271`updatedInput`, `additionalContext`, `continue: false`, `stopReason`, and362`updatedInput`, `additionalContext`, `continue: false`, `stopReason`, and

272`suppressOutput` are parsed but not supported yet, so they fail open.363`suppressOutput` are parsed but not supported yet, so they fail open.

273 364

365### PermissionRequest

366

367`PermissionRequest` runs when Codex is about to ask for approval, such as a

368shell escalation or managed-network approval. It can allow the request, deny

369the request, or decline to decide and let the normal approval prompt continue.

370It doesn't run for commands that don't need approval.

371

372`matcher` is applied to `tool_name` and matcher aliases. Current canonical

373values include `Bash`, `apply_patch`, and MCP tool names such as

374`mcp__server__tool`; `apply_patch` also matches `Edit` and `Write`.

375

376Fields in addition to [Common input fields](#common-input-fields):

377

378| Field | Type | Meaning |

379| ------------------------ | ---------------- | --------------------------------------------------------------------------------------------------------- |

380| `turn_id` | `string` | Codex-specific extension. Active Codex turn id |

381| `tool_name` | `string` | Canonical hook tool name, such as `Bash`, `apply_patch`, or an MCP name like `mcp__fs__read` |

382| `tool_input` | `JSON value` | Tool-specific input. `Bash` and `apply_patch` use `tool_input.command` while MCP tools send all the args. |

384

385Plain text on `stdout` is ignored.

386

387To approve the request, return:

388

389```json

390{

391 "hookSpecificOutput": {

392 "hookEventName": "PermissionRequest",

393 "decision": {

394 "behavior": "allow"

395 }

396 }

397}

398```

399

400To deny the request, return:

401

402```json

403{

404 "hookSpecificOutput": {

405 "hookEventName": "PermissionRequest",

406 "decision": {

407 "behavior": "deny",

408 "message": "Blocked by repository policy."

409 }

410 }

411}

412```

413

414If multiple matching hooks return decisions, any `deny` wins. Otherwise, an

415`allow` lets the request proceed without surfacing the approval prompt. If no

416matching hook decides, Codex uses the normal approval flow.

417

418Don't return `updatedInput`, `updatedPermissions`, or `interrupt` for

419`PermissionRequest`; those fields are reserved for future behavior and fail

420closed today.

421

274### PostToolUse422### PostToolUse

275 423

276Currently `PostToolUse` only supports Bash tool results. It is not limited to424`PostToolUse` runs after supported tools produce output, including Bash,

277commands that exit successfully: non-interactive `exec_command` calls can still425`apply_patch`, and MCP tool calls. For Bash, it also runs after commands that

278trigger `PostToolUse` when Codex emits a Bash post-tool payload. It cannot undo426exit with a non-zero status. It can't undo side effects from the tool that

279side effects from the command that already ran.427already ran.

428

429This doesn't intercept all shell calls yet, only the simple ones. The newer

430 `unified_exec` mechanism allows richer streaming stdin/stdout handling of

431 shell, but interception is incomplete. Similarly, this doesn't intercept

432 `WebSearch` or other non-shell, non-MCP tool calls.

280 433

281`matcher` is applied to `tool_name`, which currently always equals `Bash`.434`matcher` is applied to `tool_name` and matcher aliases. For file edits through

435`apply_patch`, matchers can use `apply_patch`, `Edit`, or `Write`; hook input

436still reports `tool_name: "apply_patch"`.

282 437

283Fields in addition to [Common input fields](#common-input-fields):438Fields in addition to [Common input fields](#common-input-fields):

284 439

286| --- | --- | --- |441| --------------- | ------------ | --------------------------------------------------------------------------------------------------------- |

292 447

293Plain text on `stdout` is ignored.448Plain text on `stdout` is ignored.

294 449

307 462

308That `additionalContext` text is added as extra developer context.463That `additionalContext` text is added as extra developer context.

309 464

310For this event, `decision: "block"` does not undo the completed Bash command.465For this event, `decision: "block"` doesn't undo the completed Bash command.

311Instead, Codex records the feedback, replaces the tool result with that466Instead, Codex records the feedback, replaces the tool result with that

312feedback, and continues the model from the hook-provided message.467feedback, and continues the model from the hook-provided message.

313 468

322 477

323### UserPromptSubmit478### UserPromptSubmit

324 479

325`matcher` is not currently used for this event.480`matcher` isn't currently used for this event.

326 481

327Fields in addition to [Common input fields](#common-input-fields):482Fields in addition to [Common input fields](#common-input-fields):

328 483

330| --- | --- | --- |485| --------- | -------- | ---------------------------------------------- |

333 488

334Plain text on `stdout` is added as extra developer context.489Plain text on `stdout` is added as extra developer context.

335 490

360 515

361### Stop516### Stop

362 517

363`matcher` is not currently used for this event.518`matcher` isn't currently used for this event.

364 519

365Fields in addition to [Common input fields](#common-input-fields):520Fields in addition to [Common input fields](#common-input-fields):

366 521

368| --- | --- | --- |523| ------------------------ | ---------------- | ------------------------------------------------- |

372 527

373`Stop` expects JSON on `stdout` when it exits `0`. Plain text output is invalid528`Stop` expects JSON on `stdout` when it exits `0`. Plain text output is invalid

374for this event.529for this event.

385 540

386You can also use exit code `2` and write the continuation reason to `stderr`.541You can also use exit code `2` and write the continuation reason to `stderr`.

387 542

388For this event, `decision: "block"` does not reject the turn. Instead, it tells543For this event, `decision: "block"` doesn't reject the turn. Instead, it tells

389Codex to continue and automatically creates a new continuation prompt that acts544Codex to continue and automatically creates a new continuation prompt that acts

390as a new user prompt, using your `reason` as that prompt text.545as a new user prompt, using your `reason` as that prompt text.

391 546

hooks.md Codex Docs, 2026-04-08 00:40 UTC → 2026-05-05 23:00 UTC