Hook Prompt Has Field

Hook handlers with "type": "prompt" or "type": "agent" MUST include a "prompt" field containing the instruction text. Without it, Claude Code has no prompt to inject and the hook does nothing.

Antipatterns

• Prompt handler without prompt field. Defining "type": "prompt" with a "matcher" but no "prompt" field. Claude Code has no instruction text to inject.
• Using command field instead of prompt. Setting "type": "prompt" with a "command" field — the handler expects "prompt" for instruction text, not "command".
• Agent handler missing prompt. Defining "type": "agent" without a "prompt" field. Agent handlers also require a prompt to define the sub-agent's task.

Pass / Fail

Pass

{
  "hooks": {
    "PreToolUse": [
      { "type": "prompt", "prompt": "Check for security issues before proceeding" }
    ]
  }
}

Fail

{
  "hooks": {
    "PreToolUse": [
      { "type": "prompt", "matcher": "Edit" }
    ]
  }
}

Limitations

Checks that at least one "prompt" field exists. Does not verify the prompt pairs correctly with a "type": "prompt" or "type": "agent" handler.