# API Key Management

## Objective

Let users create and control API credentials without ever showing a secret twice.

A self-serve screen for issuing, scoping, rotating, and revoking API keys, with secrets stored only as hashes.

## Before You Begin

This feature is being added to an application that already exists and already
works. Do not scaffold a new project, and do not assume a blank slate.

Inspect the codebase first and establish:

- The existing application structure and where code of this kind already lives.
- The framework and version in use.
- The existing design system — colours, spacing, typography, and component conventions.
- Existing UI components you can reuse instead of writing new ones.
- The existing database structure, if this feature needs to persist anything.
- The existing authentication and authorization system, if this feature is user-scoped.
- Dependencies already installed, so you don't add a library that duplicates one.
- The existing test setup and conventions.

Only start writing code once you understand the above. If the application
already implements part of this feature, extend it rather than replacing it.

## Implementation Instructions

1. Generate keys with a cryptographically secure random source and a recognisable prefix so leaked keys can be identified in logs and scanners.
2. Show the full secret exactly once, at creation, with a copy control and a clear warning that it will not be shown again. Store only a hash.
3. Give each key a name, a scope set, an optional expiry, and a last-used timestamp so users can tell which key is safe to delete.
4. Support rotation as a first-class action: issue a replacement while the old key stays valid for a short overlap, then revoke it.
5. Do NOT log, email, or include the raw secret in any audit record, error report, or support view. The hash is the only copy the system keeps.

## UI and UX Requirements

Match the application's existing design system exactly. Reuse its components,
spacing, and typography. This feature should look like it was always there.

## Responsive Requirements

Works on mobile, tablet, and desktop. Touch targets are large enough to hit on a
phone, and nothing overflows horizontally at 320px.

## Accessibility Requirements

- Fully keyboard navigable.
- Correct semantic elements and ARIA roles.
- Visible focus states.
- Meets WCAG AA contrast.
- Dynamic changes are announced to screen readers.
- Respects prefers-reduced-motion.

## Edge Cases

- Revocation must invalidate cached authentication immediately, not at the next cache expiry.
- A key with an expiry must stop working at the expiry, and the owner should be warned before it lapses.
- Verify keys with a constant-time comparison against the hash.
- A key must never carry more permission than the user who created it has now — re-check on use, not just at issue.
- Per-key rate limits are useful, but the account-level limit still applies; one key must not be able to spend the whole account budget.
- Deleting a user or removing them from a workspace must revoke the keys they issued.

## Testing

Exercise the feature end to end in the running application. Cover every edge case
above, then run the existing test suite and confirm nothing regressed.

## Acceptance Criteria

- [ ] The raw secret is displayed once and never retrievable afterwards.
- [ ] Only a hash of the key is stored, and comparison is constant-time.
- [ ] Keys have names, scopes, optional expiry, and last-used timestamps.
- [ ] Rotation issues a new key with a defined overlap window.
- [ ] Revocation takes effect immediately, including behind caches.
- [ ] Key creation, rotation, and revocation are audited without the secret.
- [ ] The feature matches the existing design system.
- [ ] No existing functionality is broken.

## Adaptation Rules

- Match the existing design system. Do not introduce a new colour palette,
  spacing scale, or component library.
- Reuse existing components and utilities wherever they fit.
- Follow the naming, file layout, and code style already present.
- Do not upgrade, replace, or remove existing dependencies to make this
  feature fit. Adapt the feature to the app, not the app to the feature.
- Do not break existing functionality. If a change is genuinely required in
  existing code, make the smallest one that works and say so.
- If something in these instructions conflicts with how the application is
  built, follow the application and explain the deviation.

## Final Verification

Before you report the work as done:

1. Re-read the acceptance criteria above and check each one against what you
   actually built.
2. Run the application and exercise the feature end to end.
3. Run the existing test suite and confirm you have broken nothing.
4. Check the feature on mobile, tablet, and desktop widths.
5. Check keyboard navigation and focus handling.
6. Summarize what changed: files added, files modified, and anything you
   deliberately did differently because of how this application is built.

If any acceptance criterion is unmet, fix it before reporting completion.