# Agents on Rails: lemans goes open source

DevFeed: [Agents on Rails: lemans goes open source](<https://devfeed.tech/articles/agents-on-rails-lemans-goes-open-source-3561.md>)

Original publisher: [Read original article](<https://rubyonrails.org/2026/8/24/agents-on-rails-lemans>)

Author: Vladimir Dementyev, Svyatoslav Kryukov, Artur Petrov

Published: 2026-08-24T00:00:00Z

Content type: release

Language: en

Sources: [Ruby on Rails: Compress the complexity of modern web apps](<https://devfeed.tech/sources/ruby-on-rails-compress-the-complexity-of-modern-web-apps.md>)

Topics: [AI Chat](<https://devfeed.tech/topics/ai-chat.md>)

Tags: [agents](<https://devfeed.tech/tags/agents.md>), [api](<https://devfeed.tech/tags/api.md>), [benchmark](<https://devfeed.tech/tags/benchmark.md>), [llm](<https://devfeed.tech/tags/llm.md>), [models](<https://devfeed.tech/tags/models.md>), [open-source](<https://devfeed.tech/tags/open-source.md>), [openai](<https://devfeed.tech/tags/openai.md>), [python](<https://devfeed.tech/tags/python.md>), [qwen](<https://devfeed.tech/tags/qwen.md>), [ruby](<https://devfeed.tech/tags/ruby.md>), [tooling](<https://devfeed.tech/tags/tooling.md>)

## AI overview

lemans, the harness used for Agents on Rails results, is now open source. The article reports benchmark results for Sonnet 5, Terra, Qwen 3.8-27B, and ox-alpha, comparing scores, runtime, cost, and Rails API recall.

## Source excerpt

Another week, another step for Agents on Rails. This one is a big one: lemans, the harness behind every number we've published, is now open source. We also ran four new models: Sonnet 5, Terra, an open-weight Qwen you can run on your own machine, and one that won't tell us its name.