# Rails Foundation

> The Rails Foundation commissioned Evil Martians to build Agents on Rails: an ongoing benchmark measuring how well coding agents perform on real Rails codebases. We built lemans, the open source harness behind it.

- URL: https://evilmartians.com/clients/rails-foundation
- Industries: Developer Tools, AI
- Services: LLM benchmarking, UI coding harness, SDKs, extensions & plugins

## Key facts

- **16+**: models benchmarked

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Rails programmers kept saying that Rails and AI pair well together, that Convention over Configuration makes Rails token-efficient, that models tend to write good Rails. The Rails Foundation wanted more than anecdotes, so it commissioned Evil Martians to measure it. We designed and built the harness and task corpus, ran the evals, and published the results. The harness is lemans, now open source: it runs agents in a sandbox they can’t escape, and grades them with tests they can’t tamper with.