Hook stderr output shows raw command path as prefix, leaking implementation details

[iroha924]

Description

When a hook writes to stderr (e.g., exit 2 for DENY/block), Claude Code displays the message with the full command as a prefix:

Stop hook error: [node /path/to/hook.mjs stop]: Custom message here.

The [node /path/to/hook.mjs stop] prefix is an implementation detail that provides no value to users. For plugin hooks, it exposes internal paths like ${CLAUDE_PLUGIN_ROOT}/dist/hook.mjs.

Expected behavior

Show only the hook's stderr message, optionally with a human-readable hook identifier:

Stop hook: Custom message here.

Or use the plugin name if available:

my-plugin (Stop): Custom message here.

Reproduction

1. Create a minimal hook that exits with code 2:

{
  "hooks": {
    "Stop": [
      {
        "hooks": [
          {
            "type": "command",
            "command": "echo 'Please fix errors before finishing.' >&2 && exit 2",
            "timeout": 5
          }
        ]
      }
    ]
  }
}

2. Start a session and let Claude attempt to stop
3. Observe the output:

Stop hook error: [echo 'Please fix errors before finishing.' >&2 && exit 2]: Please fix errors before finishing.

The full command is shown as a prefix, and the intentional block is labeled "error".

Additional context

• The word "error" is misleading for intentional blocking behavior (exit 2). Related: SessionStart hook shows 'hook error' despite successful execution (exit 0) #12671, PreToolUse hook shows 'error' label even for successful (exit 0) hook runs #17088
• When both plugin hooks and settings hooks define hooks for the same event, the message appears multiple times with different command paths, making it look like separate errors
• Plugin authors have no control over this formatting

[github-actions]

Found 3 possible duplicate issues:

1. Hook systemMessage display: redundant prefix wastes screen space #32624
2. Stop hook with exit code 2 displays as 'Stop hook error' instead of feedback #34600
3. Distinguish hook denial from hook error in PreToolUse output #31592

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🤖 Generated with Claude Code

[iroha924]

The "error" label issue overlaps with #34600 and #31592. However, this issue also covers a separate problem not addressed there:

The raw command path is exposed in the output prefix. For example:

[node ${CLAUDE_PLUGIN_ROOT}/dist/hook.mjs stop]: ...

This leaks implementation details (internal paths, plugin cache structure) that provide no value to users. Plugin authors have no control over this formatting.

Closing #34600 / #31592 would not resolve this aspect.

[github-actions]

Closing for now — inactive for too long. Please open a new issue if this is still relevant.

[github-actions]

This issue has been automatically locked since it was closed and has not had any activity for 7 days. If you're experiencing a similar issue, please file a new issue and reference this one if it's relevant.