One person is driving this. The headline number reflects a single contributor's workflow, not a project-wide shift.
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: 77.1%. Bars are scaled to that peak, not to 100%.
Which agents
| Claude Code | Anthropic | 868 | 54.8% |
| GitHub Copilot | GitHub | 1 | 0.1% |
Verify it yourself
Sample commits that matched. Every one links to GitHub — check the trailers.
9c508d2bBUG: read_stata decoded far-out dates to silently wrong values (GH#36096) Claude Code2c509ccaBUG: select_dtypes byteorder and unit-multiple dt64/td64 specs (GH#40234) Claude Codeaba058b5BUG: read_csv ignored an allocation failure when building the skiprows setClaude Codec6ee3150DOC: Fix invalid Sphinx cross-references in older whatsnew RST files (#644GitHub Copilot
What was excluded
| Commits in window | 1,672 |
| Merge commits removed | −0 |
| CI / dependency bots removed | −88 |
| Considered | 1,584 |
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 pandas-dev/pandas