Problem

When Cursor IDE runs Claude Code-compatible hooks, it sends conversation_id instead of session_id in the hook input. The UserPromptSubmit hook (new-hook.ts) reads session_id directly, so it becomes undefined, and the subsequent call to /api/sessions/init fails with HTTP 400 because contentSessionId is required.

This causes Cursor to show a blocking error dialog:

Submission blocked by hook
Hook blocked with message: Hook error: Error: Session initialization failed: 400

The error happens every time a user submits a prompt in Cursor's built-in agent when claude-mem hooks are active.

Root Cause

new-hook.ts interface and destructuring only reads session_id:

// Before
const { session_id, cwd, prompt } = input;

Cursor provides conversation_id, not session_id, so contentSessionId sent to the worker is undefined → 400.

Fix

Two-part fix:

1. Accept conversation_id as fallback when session_id is absent
2. Skip gracefully (return success) when neither ID is available, instead of throwing an error that blocks the submission

// After
const session_id = input.session_id ?? input.conversation_id;
if (!session_id) {
  console.log(STANDARD_HOOK_RESPONSE);
  return;
}

Testing

Reproduced by using Cursor's built-in agent with claude-mem hooks active. After this fix, Cursor submits prompts without the blocking error.

🤖 Generated with Claude Code