Comprehensive Review: Cursor Hooks Integration

Overview

This document provides a thorough review of the Cursor hooks integration, covering all aspects from implementation details to edge cases and potential issues.

Architecture Review

✅ Strengths

1. Modular Design: Common utilities extracted to common.sh for reusability
2. Error Handling: Graceful degradation - hooks never block Cursor even on failures
3. Parity with Claude Code: Matches claude-mem's hook behavior where possible
4. Fire-and-Forget: Observations sent asynchronously, don't block agent execution

⚠️ Limitations (Platform-Specific)

1. No Windows Support: Bash scripts require Unix-like environment
   • Mitigation: Could add PowerShell equivalents or use Node.js/Python wrappers
2. Dependency on jq/curl: Requires external tools
   • Mitigation: Dependency checks added, graceful fallback

Script-by-Script Review

1. common.sh - Utility Functions

Purpose: Shared utilities for all hook scripts

Functions:

• ✅ check_dependencies() - Validates jq and curl exist
• ✅ read_json_input() - Safely reads and validates JSON from stdin
• ✅ get_worker_port() - Reads port from settings with validation
• ✅ ensure_worker_running() - Health checks with retries
• ✅ url_encode() - URL encoding for special characters
• ✅ get_project_name() - Extracts project name with edge case handling
• ✅ json_get() - Safe JSON field extraction with array support
• ✅ is_empty() - Null/empty string detection

Edge Cases Handled:

• ✅ Empty stdin
• ✅ Malformed JSON
• ✅ Missing settings file
• ✅ Invalid port numbers
• ✅ Windows drive roots (C:, etc.)
• ✅ Empty workspace roots
• ✅ Array field access (workspace_roots[0])

Potential Issues:

• ⚠️ url_encode() uses jq - if jq fails, encoding fails silently
• ✅ Fixed: Falls back to original string if encoding fails

2. session-init.sh - Session Initialization

Purpose: Initialize claude-mem session when prompt is submitted

Flow:

1. Read and validate JSON input
2. Extract session_id, project, prompt
3. Ensure worker is running
4. Strip leading slash from prompt (parity with new-hook.ts)
5. Call /api/sessions/init
6. Handle privacy checks

Edge Cases Handled:

• ✅ Empty conversation_id → fallback to generation_id
• ✅ Empty workspace_root → fallback to pwd
• ✅ Empty prompt → still initializes session
• ✅ Worker unavailable → graceful exit
• ✅ Privacy-skipped sessions → silent exit
• ✅ Invalid JSON → graceful exit

Potential Issues:

• ✅ Fixed: String slicing now checks for empty strings
• ✅ Fixed: All jq operations have error handling
• ✅ Fixed: Worker health check with proper retries

Parity with Claude Code:

• ✅ Session initialization
• ✅ Privacy check handling
• ✅ Slash stripping
• ❌ SDK agent init (not applicable to Cursor)

3. save-observation.sh - Observation Capture

Purpose: Capture MCP tool usage and shell commands

Flow:

1. Read and validate JSON input
2. Determine hook type (MCP vs Shell)
3. Extract tool data
4. Validate JSON structures
5. Ensure worker is running
6. Send observation (fire-and-forget)

Edge Cases Handled:

• ✅ Empty tool_name → exit gracefully
• ✅ Invalid tool_input/tool_response → default to {}
• ✅ Malformed JSON in tool data → validated and sanitized
• ✅ Empty session_id → exit gracefully
• ✅ Worker unavailable → exit gracefully

Potential Issues:

• ✅ Fixed: JSON validation for tool_input and tool_response
• ✅ Fixed: Proper handling of empty/null values
• ✅ Fixed: Error handling for all jq operations

Parity with Claude Code:

• ✅ Tool observation capture
• ✅ Privacy tag stripping (handled by worker)
• ✅ Fire-and-forget pattern
• ✅ Enhanced: Shell command capture (not in Claude Code)

4. save-file-edit.sh - File Edit Capture

Purpose: Capture file edits as observations

Flow:

1. Read and validate JSON input
2. Extract file_path and edits array
3. Validate edits array
4. Create edit summary
5. Ensure worker is running
6. Send observation (fire-and-forget)

Edge Cases Handled:

• ✅ Empty file_path → exit gracefully
• ✅ Empty edits array → exit gracefully
• ✅ Invalid edits JSON → default to []
• ✅ Malformed edit objects → summary generation handles gracefully
• ✅ Empty session_id → exit gracefully

Potential Issues:

• ✅ Fixed: Edit summary generation with error handling
• ✅ Fixed: Array validation before processing
• ✅ Fixed: Safe string slicing in summary generation

Parity with Claude Code:

• ✅ File edit capture (new feature for Cursor)
• ✅ Observation format matches claude-mem structure

5. session-summary.sh - Summary Generation

Purpose: Generate session summary when agent loop ends

Flow:

1. Read and validate JSON input
2. Extract session_id
3. Ensure worker is running
4. Send summarize request with empty messages (no transcript access)
5. Output empty JSON (required by Cursor)

Edge Cases Handled:

• ✅ Empty session_id → exit gracefully
• ✅ Worker unavailable → exit gracefully
• ✅ Missing transcript → empty messages (worker handles gracefully)

Potential Issues:

• ✅ Fixed: Proper JSON output for Cursor stop hook
• ✅ Fixed: Worker handles empty messages (verified in codebase)

Parity with Claude Code:

• ⚠️ Partial: No transcript access, so no last_user_message/last_assistant_message
• ✅ Summary generation still works (based on observations)

6. context-inject.sh - Context Injection via Rules File

Purpose: Fetch context and write to .cursor/rules/ for auto-injection

How It Works:

1. Fetches context from claude-mem worker
2. Writes to .cursor/rules/claude-mem-context.mdc with alwaysApply: true
3. Cursor auto-includes this rule in all chat sessions
4. Context refreshes on every prompt submission

Flow:

1. Read and validate JSON input
2. Extract workspace root
3. Get project name
4. Ensure worker is running
5. Fetch context from /api/context/inject
6. Write context to .cursor/rules/claude-mem-context.mdc
7. Output {"continue": true}

Edge Cases Handled:

• ✅ Empty workspace_root → fallback to pwd
• ✅ Worker unavailable → allow prompt to continue
• ✅ Context fetch failure → allow prompt to continue (no file written)
• ✅ Special characters in project name → URL encoded
• ✅ Missing .cursor/rules/ directory → created automatically

Parity with Claude Code:

• ✅ Context injection achieved via rules file workaround
• ✅ Worker readiness check matches Claude Code
• ✅ Context available immediately in next prompt

Error Handling Review

✅ Comprehensive Error Handling

1. Input Validation:

   • ✅ Empty stdin → default to {}
   • ✅ Malformed JSON → validated and sanitized
   • ✅ Missing fields → safe fallbacks

2. Dependency Checks:

   • ✅ jq and curl existence checked
   • ✅ Non-blocking (warns but continues)

3. Network Errors:

   • ✅ Worker unavailable → graceful exit
   • ✅ HTTP failures → fire-and-forget (don't block)
   • ✅ Timeout handling → 15 second retries

4. Data Validation:

   • ✅ Port number validation (1-65535)
   • ✅ JSON structure validation
   • ✅ Empty/null value handling

Security Review

✅ Security Considerations

1. Input Sanitization:

   • ✅ JSON validation prevents injection
   • ✅ URL encoding for special characters
   • ✅ Worker handles privacy tag stripping

2. Error Information:

   • ✅ Errors don't expose sensitive data
   • ✅ Fire-and-forget prevents information leakage

3. Dependency Security:

   • ✅ Uses standard tools (jq, curl)
   • ✅ No custom code execution

Performance Review

✅ Performance Optimizations

1. Non-Blocking:

   • ✅ All hooks exit quickly (don't block Cursor)
   • ✅ Observations sent asynchronously

2. Efficient Health Checks:

   • ✅ 200ms polling interval
   • ✅ 15 second maximum wait
   • ✅ Early exit on success

3. Resource Usage:

   • ✅ Minimal memory footprint
   • ✅ No long-running processes
   • ✅ Fire-and-forget HTTP requests

Testing Recommendations

Unit Tests Needed

1. common.sh functions:

   • Test json_get() with various field types
   • Test get_project_name() with edge cases
   • Test url_encode() with special characters
   • Test ensure_worker_running() with various states

2. Hook scripts:

   • Test with empty input
   • Test with malformed JSON
   • Test with missing fields
   • Test with worker unavailable
   • Test with invalid port numbers

Integration Tests Needed

1. End-to-end flow:

   • Session initialization → observation capture → summary
   • Multiple concurrent hooks
   • Worker restart scenarios

2. Edge cases:

   • Very long prompts/commands
   • Special characters in paths
   • Unicode in tool inputs
   • Large file edits

Known Limitations

1. Cursor Hook System:

   • ✅ Context injection solved via .cursor/rules/ file
   • ❌ No transcript access for summary generation
   • ❌ No SessionStart equivalent

2. Platform Support:

   • ⚠️ Bash scripts (Unix-like only)
   • ⚠️ Requires jq and curl

3. Context Injection:

   • ✅ Solved via auto-updated .cursor/rules/claude-mem-context.mdc
   • ✅ Context also available via MCP tools
   • ✅ Context also available via web viewer

Recommendations

Immediate Improvements

1. ✅ DONE: Comprehensive error handling
2. ✅ DONE: Input validation
3. ✅ DONE: Dependency checks
4. ✅ DONE: URL encoding

Future Enhancements

1. Logging: Add optional debug logging to help troubleshoot
2. Metrics: Track hook execution times and success rates
3. Windows Support: PowerShell or Node.js equivalents
4. Testing: Automated test suite
5. Documentation: More examples and troubleshooting guides

Conclusion

The Cursor hooks integration is production-ready with:

• ✅ Comprehensive error handling
• ✅ Input validation and sanitization
• ✅ Graceful degradation
• ✅ Feature parity with Claude Code hooks (where applicable)
• ✅ Enhanced features (shell/file edit capture)

The implementation handles edge cases well and follows best practices for reliability and maintainability.