Adoption is broad. Many contributors are committing agent-authored work, which is what a real organisational rollout looks like.
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: 5.4%. Bars are scaled to that peak, not to 100%.
Which agents
| GitHub Copilot | GitHub | 16 | 2.5% |
| Claude Code | Anthropic | 4 | 0.6% |
Verify it yourself
Sample commits that matched. Every one links to GitHub — check the trailers.
deed9c0dGH-49237: [R] Deprecate Feather reader and writer (#49276)GitHub Copilot3d771d08GH-50481: [C++] Fix CSV reader mis-parsing rows with an embedded NUL byte GitHub Copilot07c40ba1GH-39961: [C++][Python] Propagate CSV parse delimiter to write options (#4GitHub Copilot2a526c1eGH-35806: [R] Improve error message for null type inference with sparse CSClaude Codeca684524GH-49486: [CI][C++] Fix Meson build missing tensor extension sources (#494Claude Code9e82bc2aGH-49458: [CI][C++] Fix Meson build referencing non-existent fixed_shape_tClaude Code
What was excluded
| Commits in window | 659 |
| Merge commits removed | −0 |
| CI / dependency bots removed | −20 |
| Considered | 639 |
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 apache/arrow