A new project called leanrea benchmarked what happens when you replace a 207-tool MCP server (REA) with a single 8 KB markdown skill that lets the agent run raw CLI commands directly through Bash.
On Claude Code 2.1 (Sonnet 5.5, macOS) across four reverse-engineering tasks:
- 38% less wall time (388s vs 627s)
- 35% lower cost (.17 vs .36)
- 60% fewer tokens (2.40M vs 5.93M)
- Same score (74/75 vs 75/75)
Frontier models already know standard flags for , , , , and . When you wrap every Unix flag in a custom JSON schema, you pay context tax on every prompt just to parse an unfamiliar API abstraction.
Full writeup and breakdown: https://reidmarlow.com/stop-wrapping-cli-tools-in-200-mcp-endpoints
