Build And Test FFI Surface

Companion Guidance

Use karpathy-guidelines alongside this skill for implementation or review work. Keep changes scoped, surface assumptions, and define focused validation before editing.

Use this skill when the change is primarily in crates/ffi, the generated header, or ABI-facing behavior consumed by Go or external native callers.

Default Path

1. Rebuild the FFI crate in release mode so the shared library and header stay

in sync.

1. Run cargo fmt --all because FFI work is Rust work.
2. Run just test-rust.
3. Run cargo clippy --workspace --all-targets -- -D warnings.
4. Check the generated header diff when any exported symbol or type changed.
5. If downstream consumers changed too, run their binding-specific skills next.

Common Commands

# Rebuild the shared library with the repo wrapper used by FFI consumers
just build-go

# Required Rust validation
cargo fmt --all
just test-rust
cargo test -p nemo-relay-ffi
cargo clippy --workspace --all-targets -- -D warnings

# Review header drift if the FFI surface changed
git diff -- crates/ffi/nemo_relay.h

When To Escalate

• If Go behavior changed, also use test-go-binding.
• If the FFI change reflects shared runtime semantics rather than a pure bridge

change, also use validate-change.

References

• crates/ffi/Cargo.toml
• crates/ffi/build.rs
• crates/ffi/cbindgen.toml
• crates/ffi/nemo_relay.h
• just build-go
• .pre-commit-config.yaml
• README.md
• validate-change