Run uv run --project=./python/py-fuzzer fuzz -h from the repository root for more information and example invocations (requires uv to be installed).

The --write-github-issue option is intended for CI workflows. It writes a Markdown issue body when the fuzzer finds bugs. The report includes as many reproducers as fit in a GitHub issue, with the original generated source when minimization fails or times out. When writing a report, the fuzzer requires GITHUB_SERVER_URL, GITHUB_REPOSITORY, and GITHUB_RUN_ID to be set. If any are missing, it exits with an error. These are the GitHub server URL, OWNER/REPO, and run ID from the workflow URL; GitHub Actions sets them automatically.

For example, a GitHub Actions workflow can build Ruff and fuzz it using seeds 0 through 10 inclusive:

uv run --project=./python/py-fuzzer fuzz --bin=ruff --write-github-issue=fuzz-issue.md 0-10

The report identifies the test executable's build commit. The file is only written if bugs are found. The fuzzer exits with status 1 when it finds bugs and 0 when it finds none.