Anthropic researcher Nicholas Carlini asked 16 Claude agents to write a C compiler, the program that translates C source code into instructions a computer can run. The team produced a compiler capable of building Linux 6.9 on several processor architectures, he reports. One difficulty was turning a broken kernel build into separate jobs agents could work on in parallel.
Carlini used GCC, an established compiler, as a comparison tool. His test system compiled most source files with GCC and a selected subset with the agents' compiler. If the combined build failed, the agents could narrow the search to a smaller set of files. Different agents could investigate different parts of the problem.
The experiment took nearly 2,000 Claude Code sessions and about $20,000 in API charges, according to Carlini. The compiler is an inspectable artifact. The testing setup helps explain what made the work possible and how much of the job still fell to the person organizing it.