Know what every error means, and how to fix it.

Know what every error means, and how to fix it.

ErrLookup reads library source and documents every user-facing error: exact message, cause, ordered fixes, defensive patterns. Built for coding agents, answer engines, and humans.

Install the MCP server Request a library

1,491errors documented

9repositories

2026-08-01dataset version

See it in action

opencode hits an `AxiosError`, asks the ErrLookup MCP server what it means, and applies the fix the library authors recommend.

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Give your coding agent error superpowers

{ "mcpServers": { "errlookup": { "command": "npx", "args": [ "-y", "@standardbeagle/errlookup-mcp" ] } } }

The MCP server caches the dataset locally: offline-capable, no API keys, answers `search_error` straight from disk.

Analyzed repos

| Repo | Language | Errors | Stars | | ------------------------------------------------------------------------- | ---------- | ------ | ------- | | sindresorhus/is | TypeScript | 100 | 1,790 | | axios/axios | JavaScript | 45 | 109,164 | | expressjs/express | JavaScript | 22 | 69,287 | | clap-rs/clap | Rust | 4 | 16,597 | | pallets/flask | Python | 66 | 72,016 | | psf/requests | Python | 37 | 54,203 | | gohugoio/hugo | Go | 545 | 89,267 | | docker/cli | Go | 668 | 5,980 | | tokio-rs/tokio | Rust | 4 | 32,741 |

Missing a library you depend on? Request a crawl.

Honest provenance: every record is AI-assisted analysis of the cited commit, pinned to its SHA. See how records are made and the dataset contract.