Notification hook (permission_prompt / idle_prompt) never invoked in VSCode extension, works correctly in terminal CLI

Title: Notification hook (permission_prompt / idle_prompt) never invoked in VSCode extension, works correctly in terminal CLI

Environment

• Claude Code: VSCode native extension (also tested terminal/CLI build for comparison)
• OS: Linux (Ubuntu 24.04, kernel 6.17.0-35-generic)

Summary
A Notification hook configured in ~/.claude/settings.json (global settings) fires correctly and reliably when Claude Code runs in a plain terminal, but is never invoked when Claude Code runs as the VSCode extension — despite identical, validated configuration and multiple full restarts of VSCode.

Configuration used

{
  "hooks": {
    "Notification": [
      {
        "matcher": "permission_prompt|idle_prompt",
        "hooks": [
          { "type": "command", "command": "~/.claude/hooks/alert.sh" }
        ]
      }
    ]
  }
}

Steps to reproduce

1. Add the above Notification hook to ~/.claude/settings.json, pointing to a script that logs invocation (e.g. writes a timestamped line + stdin JSON to a debug file).
2. Open a Claude Code session inside the VSCode extension.
3. Trigger a permission prompt (e.g. run a Bash command not covered by the permission allowlist) and/or wait idle long enough to trigger idle_prompt.
4. Check the debug log file.

Expected
The hook command runs on every permission_prompt and idle_prompt Notification event, same as in the terminal build.

Actual

• In the VSCode extension: the debug log file stays completely empty — 0 invocations — across multiple permission prompts, a 4+ minute idle wait, two full VSCode restarts, and a second session started in parallel.
• In a plain terminal session (same machine, same ~/.claude/settings.json, unchanged): the exact same hook fires correctly and repeatedly. Debug log captured real payloads, e.g.:

``json
{"session_id":"...","transcript_path":"...","cwd":"/home/cms","hook_event_name":"Notification","message":"Claude needs your permission","notification_type":"permission_prompt"}
`
Desktop notification (notify-send) and sound (paplay/aplay`) both fired as expected.

Additional notes

• The VSCode extension does show its own native "switch back to this window" nudge when attention is needed — this is a separate, undocumented built-in mechanism, distinct from the Notification hook, and does not include a sound.
• The Claude Code docs' feature-parity table (CLI vs VSCode extension) does not list hooks as a CLI-only feature, nor does it clarify whether specific hook event types (as opposed to hook handler types like command/http/agent) are supported in the extension surface.

Ask
Please clarify (and fix, if unintended) whether Notification hooks — and hooks in general — are expected to fire inside the VSCode extension. If this is a known/intentional limitation, it should be documented in the feature-parity table.