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: 0.2%. Bars are scaled to that peak, not to 100%.
Which agents
| Claude Code | Anthropic | 7 | 0% |
| Other / generic agent | Various | 1 | 0% |
| GitHub Copilot | GitHub | 1 | 0% |
Verify it yourself
Sample commits that matched. Every one links to GitHub — check the trailers.
0b305924Follow symlinks when discovering prebuilt rustc proc-macro dylibsClaude Code80db8195internal: add `Module::path_segments`, dedup the path-to-root name walkClaude Code2ff723e9internal: Use itertools's `collect_array` in `replace_if_let_with_match`Claude Code9846cb6fMake `char::is_default_ignorable` unstably publicOther / generic agentd560d3a4Add test for async Send inference with PhantomData<*mut ()> + unsafe impl GitHub Copilot
What was excluded
| Commits in window | 22,479 |
| Merge commits removed | −8,342 |
| CI / dependency bots removed | −24 |
| Considered | 14,113 |
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 rust-lang/rust