# Sensitive Field Reveal

## Objective

Let users check a password or token without leaving it on screen.

A consistent show/hide control for passwords, API keys, and other private values.

## 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. Apply one reveal control to every sensitive field in the app rather than styling each form differently.
2. Preserve cursor position and any text selection when toggling — losing the caret mid-typing is the reason people abandon these controls.
3. Label the button by its action and update the label with the state, and expose the state to assistive technology rather than relying on an icon swap.
4. Auto-hide high-value secrets after a short idle period or on blur, and always start hidden after a page load.
5. Do NOT offer reveal on values the server only returns masked. A toggle that reveals asterisks is worse than no toggle.

## 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

- The revealed value must not be exposed to browser autofill heuristics or password managers as a plain field.
- Copying a hidden value must copy the real value, not the mask.
- Revealed state must never persist across navigation or reload.
- Screenshot and screen-share risk is why timed auto-hide exists — pick the timeout deliberately and document it.
- The toggle must be reachable by keyboard and must not sit inside the field's tab order in a way that traps the user.
- A field the user cannot read at all — a write-only secret — needs a clear explanation instead of a disabled eye icon.

## 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

- [ ] All sensitive fields use the same reveal control.
- [ ] Toggling preserves cursor position and selection.
- [ ] The button's accessible name reflects the current state.
- [ ] Fields start hidden on every load and auto-hide after the documented idle period.
- [ ] Server-masked values do not offer a reveal toggle.
- [ ] The control is fully keyboard operable.
- [ ] 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.