Github just rewrote its own ai product's runtime in rust, mostly with the ai product. the copilot…
github just rewrote its own ai product's runtime in rust, mostly with the ai product. the copilot agent runtime is now 832,000 lines of rust, merged in 128 pull requests, and copilot itself did most of the writing, per the september 17 github blog post.
dogfooding is now the migration strategy.
Context
GitHub's blog of 16 September 2026 reports more than 800,000 lines of production Rust, written mostly by AI agents across 128 pull requests, with about 830,000 production Rust lines at the end, using the Copilot app and Copilot CLI and led by one developer. The New Stack, 17 September 2026, covers it alongside an Anthropic Rust migration.
The 800,000 plus, 128 pull requests and mostly agent-written claims are first-party. September 17 is The New Stack's date; the blog is dated 16 September. Copilot itself did most of the writing is a fair gloss only with the human lead noted. Same GitHub post as the earlier Rust note. Dogfooding is now the migration strategy is the author's take.
The post's own sentence says that by 21 August the runtime was 100 percent production Rust, with 832,378 lines of production Rust and 468,689 lines of Rust unit tests. So 832,000 is a rounding of the production count as of that date, excluding tests; the post also says more than 800,000 in prose and approximately 830,000 in a chart caption, and does not state the count on the post date.
Related work
- Earlier note on the same GitHub post ↗Same blog source.
Watch next
- Independent reproduction of the cost claims.
Sources
Provenance
The note above is reproduced unedited from the original post, first published on Threads on 21 September 2026 at 00:06 IST. Sources are the papers and datasets the note draws on.
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