Hook Handler Has Type

Each hook handler object in .gemini/settings.json MUST contain a "type" field set to command. The inherited Gemini-CLI hooks contract supports only command. Without a type field, the agent cannot dispatch the handler and the hook silently does nothing.

Antipatterns

• Missing type field. Defining a handler with only "command" but no "type" key.
• Invalid type value. Setting "type": "prompt", "type": "shell", or "type": "script" — only command is supported. (prompt is a Claude-specific hook type and is not recognized here.)

Pass / Fail

Pass

{
  "hooks": {
    "SessionStart": [
      { "type": "command", "command": "echo hook" }
    ]
  }
}

Fail

{
  "hooks": {
    "SessionStart": [
      { "command": "echo hook" }
    ]
  }
}

Limitations

Checks that at least one handler has a valid type field. Does not verify every handler individually. The handler contract is inherited from Gemini CLI pending accessible Antigravity hook documentation.