ChatGPT and Codex docs

{
  "chars": 4172,
  "content": "## Matcher patterns\n\nThe `matcher` field is a regex string that filters when hooks fire. Use `\"*\"`,\n`\"\"`, or omit `matcher` entirely to match every occurrence of a supported\nevent.\n\nOnly some current Codex events honor `matcher`:\n\n| Event               | What `matcher` filters | Notes                                                          |\n| ------------------- | ---------------------- | -------------------------------------------------------------- |\n| `PermissionRequest` | tool name              | Support includes `Bash`, `apply_patch`\\*, and MCP tool names   |\n| `PostToolUse`       | tool name              | See [Tool coverage](#tool-coverage)                            |\n| `PostCompact`       | compaction trigger     | Values are `manual` or `auto`                                  |\n| `PreCompact`        | compaction trigger     | Values are `manual` or `auto`                                  |\n| `PreToolUse`        | tool name              | See [Tool coverage](#tool-coverage)                            |\n| `SessionEnd`        | end reason             | Currently only `other`                                         |\n| `SessionStart`      | start source           | Values are `startup`, `resume`, `clear`, `compact`, and `fork` |\n| `SubagentStart`     | subagent type          | Values depend on the subagent that starts                      |\n| `SubagentStop`      | subagent type          | Values depend on the subagent that stops                       |\n| `UserPromptSu",
  "description": "Run scripts or MCP tools during the Codex lifecycle",
  "markdown_url": "https://learn.chatgpt.com/docs/hooks.md",
  "observed_at_ms": 1792515977843,
  "outline": [
    {
      "anchor": null,
      "level": 1,
      "text": "Hooks"
    },
    {
      "anchor": "where-codex-looks-for-hooks",
      "level": 2,
      "text": "Where Codex looks for hooks"
    },
    {
      "anchor": "review-and-trust-hooks",
      "level": 2,
      "text": "Review and trust hooks"
    },
    {
      "anchor": "config-shape",
      "level": 2,
      "text": "Config shape"
    },
    {
      "anchor": "mcp-tool-hooks",
      "level": 2,
      "text": "MCP tool hooks"
    },
    {
      "anchor": "configure-an-mcp-tool-hook",
      "level": 3,
      "text": "Configure an MCP tool hook"
    },
    {
      "anchor": "expand-arguments-from-the-hook-event",
      "level": 3,
      "text": "Expand arguments from the hook event"
    },
    {
      "anchor": "execution-and-lifecycle",
      "level": 3,
      "text": "Execution and lifecycle"
    },
    {
      "anchor": "turn-hooks-off",
      "level": 2,
      "text": "Turn hooks off"
    },
    {
      "anchor": "managed-hooks-from-requirementstoml",
      "level": 2,
      "text": "Managed hooks from requirements.toml"
    },
    {
      "anchor": "plugin-bundled-hooks",
      "level": 2,
      "text": "Plugin-bundled hooks"
    },
    {
      "anchor": "matcher-patterns",
      "level": 2,
      "text": "Matcher patterns"
    },
    {
      "anchor": "tool-coverage",
      "level": 3,
      "text": "Tool coverage"
    },
    {
      "anchor": "common-input-fields",
      "level": 2,
      "text": "Common input fields"
    },
    {
      "anchor": "common-output-fields",
      "level": 2,
      "text": "Common output fields"
    },
    {
      "anchor": "large-hook-output",
      "level": 3,
      "text": "Large hook output"
    },
    {
      "anchor": "run-hooks-in-the-background",
      "level": 2,
      "text": "Run hooks in the background"
    },
    {
      "anchor": "configure-a-background-hook",
      "level": 3,
      "text": "Configure a background hook"
    },
    {
      "anchor": "how-background-hooks-run",
      "level": 3,
      "text": "How background hooks run"
    },
    {
      "anchor": "limitations",
      "level": 3,
      "text": "Limitations"
    },
    {
      "anchor": "hooks",
      "level": 2,
      "text": "Hooks"
    },
    {
      "anchor": "sessionstart",
      "level": 3,
      "text": "SessionStart"
    },
    {
      "anchor": "sessionend",
      "level": 3,
      "text": "SessionEnd"
    },
    {
      "anchor": "subagentstart",
      "level": 3,
      "text": "SubagentStart"
    },
    {
      "anchor": "pretooluse",
      "level": 3,
      "text": "PreToolUse"
    },
    {
      "anchor": "permissionrequest",
      "level": 3,
      "text": "PermissionRequest"
    },
    {
      "anchor": "posttooluse",
      "level": 3,
      "text": "PostToolUse"
    },
    {
      "anchor": "tool-calls-from-code-mode",
      "level": 4,
      "text": "Tool calls from code mode"
    },
    {
      "anchor": "precompact",
      "level": 3,
      "text": "PreCompact"
    },
    {
      "anchor": "postcompact",
      "level": 3,
      "text": "PostCompact"
    },
    {
      "anchor": "userpromptsubmit",
      "level": 3,
      "text": "UserPromptSubmit"
    },
    {
      "anchor": "subagentstop",
      "level": 3,
      "text": "SubagentStop"
    },
    {
      "anchor": "stop",
      "level": 3,
      "text": "Stop"
    },
    {
      "anchor": "interrupt",
      "level": 3,
      "text": "Interrupt"
    },
    {
      "anchor": "schemas",
      "level": 2,
      "text": "Schemas"
    },
    {
      "anchor": "plain-text-aliases",
      "level": 3,
      "text": "Plain-text aliases"
    }
  ],
  "section": {
    "anchor": "matcher-patterns",
    "level": 2,
    "text": "Matcher patterns"
  },
  "slug": "hooks",
  "title": "Hooks",
  "truncated": true,
  "url": "https://learn.chatgpt.com/docs/hooks"
}