Tip: Claude Code v2.1.119 Hooks Now Expose duration_ms for Tool Execution Profiling

Releasebot·medium signal

Claude Code v2.1.119 adds duration_ms to hook payloads, letting you measure how long each tool execution takes. Combined with the existing PostToolUse hook, you can build lightweight performance dashboards that track which tools are bottlenecking your sessions — e.g., identifying slow MCP server responses vs fast local reads. Use a PostToolUse hook that logs tool name + duration_ms to a CSV or SQLite to profile agent behavior over time without any external tooling.