# Contributing to Joule Code

Joule Code is one standard in the [Transaction Science Open Standards](../README.md) repository and inherits the [Charter](../CHARTER.md). Contributions scope to this subdirectory and carry the `joule-code` tag.

## What is most valuable

- **Conformance vectors.** Additional positive and negative wire vectors under [`conformance/v1/`](conformance/v1/) — especially adversarial negatives (replayed signatures, tampered edits, provenance/measured mismatches).
- **Cascade stages.** Real `L0`/`L2` stage implementations against the [`joule-code-cascade`](joule-code-rs/crates/joule-code-cascade/) trait surface.
- **Measured-energy backends.** Hardware energy interfaces feeding the receipt's `measured_uj` / `HwShunt` path (§6).
- **Third-party implementations.** An independent implementation that certifies against the public suite is the strongest validation a standard can have.

## Rules

1. **Conformance is canonicity.** A change to wire behaviour MUST come with vectors and a `conformance/VERSIONS.md` update. The vectors, not any brand, define what is correct.
2. **No floats in decision paths.** Energy is integer microjoules; canonical forms are float-free (SPEC §4).
3. **Readiness honesty.** Do not advance a part's classification (SPEC §9) past what the implementation delivers. A `measured` figure MUST come from hardware (SPEC §1.2, §6).
4. **No vanity metrics in marketing/spec/governance Markdown.** Describe shape, not size; the repository's `scripts/check-no-vanity-metrics.sh` enforces this. Identity-class facts (spec versions, RFC numbers, algorithm names, licence labels) are preserved.
5. **No capture.** No contribution may make a single steward's service a condition of core operation (SPEC §1.3).

## Process

Issues, discussions, and pull requests scope by the `joule-code` subdirectory tag. Spec-text changes (`SPEC.md`, `spec/`, `vocab/`) are CC-BY-4.0; reference-code changes (`joule-code-rs/`) are Apache-2.0. By contributing you agree your contribution is offered under the corresponding licence.