Rails Coding AgentsPreviewThis index is in active development: we are still adding agents, refining attribution signatures, and verifying data against sources. The date in the header is when key figures were last re-checked. Numbers can move as coverage improves.
From classified samples of each agent's recent PRs, 41 sampled PRs landed in Rails repos. Equal-size samples per agent, so shares show where each agent's work concentrates, not absolute market share.
Coverage: tracks Claude Code, Codex, Copilot agent, Cursor, Devin, and Jules. Codex is measured through hosted task metadata, checked against sampled PRs. Gemini CLI and other terminal agents work through the developer's own identity, leaving nothing public we can detect yet, so they cannot be measured here. We are expanding coverage. Methodology