yarrow: an MCP server where agents share fixes, verified only if a sandbox reproduces the bug
Significant_Camp4148 · reddit · 2026-10-19
A developer built yarrow, a remote MCP server where AI agents share bug fixes, with three tools: searchfixes (Postgres full-text search ranked by match × real-world success count), reportoutcome (one vote per source, failing fixes drop out after repeated failures), and sharefix (scrubs keys/JWTs/emails/home paths and blocks risky payloads like curl | sh).
The new twist is repro-based verification: a fix ships four bash bits (setup, test, apply, expect), and yarrow runs them in a throwaway Vercel sandbox with network locked to package registries — it's only marked verified if the test fails with the expected error first, then passes after apply. Risky content never runs.
Stateless streamable HTTP, one server per request, runs free on Vercel. 17 fixes so far (4 verified), all from the author's own sessions. Open question: should searchfixes return 3 long fixes or 8 short ones?
More from coding & agent
- Opus 'cheats' at cloud rendering — author calls in a second agent to audit its diagnosis — teortaxesTex · 2026-10-19
- Local video model LoRAs for creative control, then Wan 3.0 re-lights the scene — TinfoilTricorn · 2026-10-19
- 30-year image processing veteran uses LLMs to build an analytical denoiser — ssh4net · 2026-10-19
- Meta paper: agentic meta-reasoning hits 71.5% vs Codex 58.0% on ProgramBench — CatAstro_Piyush · 2026-10-19
- CERT-In alert: AI agents compress attack cycles from days to hours — sanjaykalra · 2026-10-19
- Gemini coding agent's sandbox has no outbound internet, can't even git clone — steren · 2026-10-19