Test Ffi Surface

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

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

in sync.

• Run cargo fmt --all because FFI work is Rust work.
• Run just test-rust.
• Run cargo clippy --workspace --all-targets -- -D warnings.
• Check the generated header diff when any exported symbol or type changed.
• 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