A small group is using agents. Adoption has spread beyond one person but is not project-wide.
Assisted or autonomous
Assisted — a developer’s identity authored the commit and the agent added itself as co-author. The agent ran git commit during a working session, with a person there. Autonomous — a bot identity is the author, no human in the loop. Across the whole index, 93.7% of agent commits are assisted.
Agent share by month
Peak month: 42.8%. Bars are scaled to that peak, not to 100%.
Which agents
| Claude Code | Anthropic | 1066 | 21.5% |
| GitHub Copilot | GitHub | 20 | 0.4% |
| OpenAI Codex | OpenAI | 2 | 0% |
Verify it yourself
Sample commits that matched. Every one links to GitHub — check the trailers.
135e0f84[ruby/rubygems] Allow a bundler checksum before myrack in the empty CHECKSClaude Code8398a36c[ruby/rubygems] Pend the dirs= unresolved deps test under Ruby::BoxClaude Code3f0bd4e9[ruby/rubygems] Stop resolving locally for empty CHECKSUMS entriesClaude Code762fa2fcIncrease SYNTAX_SUGGEST_TIMEOUT for ppc64le/s390x from 10 to 60 secondsGitHub Copilotd939495aFix unused variable warning in thread_sched_set_running on non-DTrace platGitHub Copilot0db07b1a[ruby/json] Avoid Float out of range warning for clearly underflowing numbGitHub Copilotf20155d5marshal.c: Make partial objects table conditionalOpenAI Codexc34cc402YJIT: Fix local register mapping overflowOpenAI Codex
What was excluded
| Commits in window | 5,075 |
| Merge commits removed | −0 |
| CI / dependency bots removed | −122 |
| Considered | 4,953 |
Bots are excluded from the denominator entirely. Counting dependabot as “AI-written code” is the fastest way to produce a meaningless number.
How this was measured
Measured over February–August 2026, cloned directly. Detection is deterministic string matching against signatures agents write about themselves — no heuristics, no style analysis. Merge commits and CI bots are excluded from the denominator. The figure is a floor: squash merges strip trailers, so real usage is higher. Contributor counts are aggregate — no individual is named.
Run it yourself: npx qmmit-cli ruby/ruby