Building a C compiler with a team of parallel Claudes
Sixteen parallel Claude agents wrote a roughly 100,000-line Rust C compiler over two weeks that boots Linux 6.9 on x86, ARM and RISC-V.
An autonomous multi-agent coding experiment that took about 2,000 Claude Code sessions and roughly $20,000 of API use, with a 99% pass rate on compiler test suites including GCC torture tests. It also builds QEMU, FFmpeg, SQLite, PostgreSQL and Redis. Its limits are no 16-bit x86 backend, no assembler or linker of its own, and slower code than GCC without optimizations.
- Date
- Thursday, 5 February 2026
- Lab
- Anthropic
- Kind
- paper
- Access
- paper only
Figures
| Measure | Value | Measured by |
|---|---|---|
| Parallel agents / sessions | 16 agents, about 2,000 sessions over two weeks | company |
| API cost | about $20,000 | company |
| Code produced | about 100,000 lines Rust C compiler | company |
Company-run demonstration, not independently reproduced. The summary of the page did not name the model; the same-day release makes Opus 4.6 likely (inference).
Sources
This record was checked against its sources on 6 October 2026. How we check