Pablo — @safetnsr

MCP servers are the backbone of agent tool access in Claude Code, Cursor, and other AI coding tools. But when your agent calls read_file 847 times in a single session, you have no idea — until now.

mcp-tracer wraps any stdio MCP server as a transparent proxy. Every JSON-RPC tool call is logged to a JSONL file with timestamps, arguments, results, and latency. Run mcp-tracer report to see exactly what happened.

One line change in your claude_desktop_config.json. Full tracing. No code changes to your server.

why

See which tools are called most (optimization target)
Measure per-tool latency
Debug MCP server issues with full request/response logs
Audit what your agent actually did with your filesystem

agent interface

mcp-tracer report --json outputs structured data for piping into other tools.

part of the safetnsr suite

Pairs with vet (code audit), pinch (cost tracking), and the rest of the @safetnsr CLI toolkit.