# AGENTS.md
Guidance for coding agents working in this repository. Humans welcome too.
## What this is
Ferroni is a 1:1 Rust port of the
[Oniguruma](https://github.com/kkos/oniguruma) regex engine. Structural
fidelity to the C original is the point: same module mapping, same function
names, same control flow.
## Language
**Project language is US English.** All code, comments, variable/function
names, commit messages, documentation files, ADRs, and test names MUST be in
English.
## Orientation
- [CONTRIBUTING.md](CONTRIBUTING.md) is the canonical preflight: build, test
suites, benchmarks, and the Unicode table regeneration scripts.
- The ADRs in `docs/app/routes/adr/` are project constraints, not decisions to
re-litigate in routine work. Read ADR-001 (1:1 parity with the C original),
ADR-004 (C-to-Rust translation patterns) and ADR-002 (`unsafe` code policy)
before changing direction.
- Conventional commits without exception; release-please depends on them.
## Testing
[CONTRIBUTING.md](CONTRIBUTING.md#running-tests) carries the runnable command
list. Debug builds need a larger thread stack; the required `RUST_MIN_STACK`
values are stated once in ADR-013
(`docs/app/routes/adr/013-stack-overflow-debug-builds.mdx`) and are reused by
CONTRIBUTING.md and the CI workflow -- do not invent a third value.
Test counts come from `./scripts/count-tests.sh`, not from memory.
Coverage is gated in CI by `./scripts/coverage.sh`; the threshold is defined
there and nowhere else. The README badge quotes the same number, so move both
together.
---
# Standards-managed repo guardrails
- Do not hand-edit managed files or standards-owned marker sections.
- If `standards check` reports drift, run `standards apply` or update standards.
- The repository's own gate may omit `standards check`; CI can still fail on it.
Node repositories:
- Fix or format every file reported by `oxfmt` whenever practical.
- For generated files, prefer formatting in the generator step.
- If formatting is not viable, use repo-local `.prettierignore`.
- Never add repo-specific ignores to managed `.oxfmtrc.json`.
Rust repositories:
- Keep `cargo fmt --all --check` and
`cargo clippy --workspace --all-targets --all-features -- -D warnings` green.
- Lint levels belong in `[workspace.lints]`, never in managed `rustfmt.toml`.
- `rust-version` in `Cargo.toml` is the only MSRV; every other mention is a
derived copy.
- Record a cargo-deny finding as a narrow, commented exception in `deny.toml` —
never by widening the org allow-list.