# Contributing to Ad+Card

Ad+Card needs skeptical implementers, privacy reviewers, accessibility experts, outfitters, and people willing to test whether the format is actually useful.

## Useful contributions

- clarify ambiguous normative language;
- add valid and invalid test vectors;
- find ways a receipt could reveal more than its claim;
- test independent wallet or instrument implementations;
- improve keyboard, screen-reader, contrast, and low-motion behavior;
- document operational and settlement failure modes;
- translate the specification without changing its meaning.

## Non-negotiable boundaries

Contributions must preserve these rules:

1. A Declaration exists because a person wrote it, not because tracking inferred it.
2. The person can hold, export, and delete their card.
3. A Receipt never upgrades uncertainty into certainty.
4. Raw location, health, image, answer, and motion data do not enter protocol objects.
5. Health-derived values do not enter eligibility or settlement.
6. Offers equip progress instead of purchasing interruption.
7. Commercial offers are funded before they are shown.

Do not submit real personal data, credentials, private evidence, production identifiers, or secrets—even in an issue or test fixture.

## Proposing a change

1. Name the exact problem and the affected object or section.
2. Include a concrete before-and-after example.
3. Explain the privacy, interoperability, and human-language impact.
4. Add or update a conformance test when behavior changes.
5. Keep product-specific mechanisms outside the protocol unless interoperability requires them.

Breaking changes require a new draft version. Silent reinterpretation of an existing receipt or assurance class is not acceptable.

## Review standard

A change is ready when a second implementation could build it without private context, a person could understand what it authorizes, and an adversarial reviewer cannot make it claim more than the evidence supports.