# Natural Language Database Query

## Objective

Answer plain-language data questions through a read-only, reviewable query path.

An internal query surface that translates a question into a restricted read-only query over an approved schema subset.

## 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. Define an approved semantic layer — the specific tables, columns, and joins this feature may touch — and expose only that to the model. Do not hand it the full schema and rely on instructions to keep it away from sensitive tables.
2. Execute through a connection that is read-only at the database level, with a row limit, a time limit, and a separate credential from the application's own. Permissions in the prompt are not permissions.
3. Parse and validate the generated query before running it: reject anything that writes, alters, calls a function outside the approved set, or touches a table outside the semantic layer. Rejection must be the default for anything unrecognised.
4. Show the query and the tables it reads alongside the results for any user permitted to see them, and log every generated query with the requesting user and the question that produced it.
5. Restrict access to this feature to operators and support staff by the app's own permission system. Customer-facing data questions belong to Natural Language Report Builder and Natural Language Filters, which run against defined metrics rather than raw tables.

## 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

- Only the approved schema subset may be reachable. A query that joins its way to a table outside the semantic layer must be rejected by the validator regardless of how reasonable it looks.
- Read-only enforcement must live in the database credential and the validator, not in the instruction to the model. A single successful write from a generated query is unrecoverable.
- Every generated query must pass validation before execution, and an unparseable or partially truncated query must be discarded rather than repaired by guesswork.
- Content stored in the database can contain text written to steer a model. Treat all query results and any row content included in a follow-up as untrusted data, never as instructions.
- Showing the query and its source tables is what makes a wrong answer detectable. A bare number with no visible query will be quoted in a meeting and never checked.
- An unbounded query can lock tables or exhaust a connection pool. Enforce row and execution-time limits and run against a replica where one exists.
- Results may contain personal data. Decide what may be sent back to the model for summarisation, redact what must not leave, and never send raw customer records simply to phrase an answer.
- When the model is unavailable, the feature should say so plainly. Do not fall back to executing a stored guess or a previous session's query.

## 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 model can reference only the approved semantic layer, and queries touching anything else are rejected.
- [ ] Execution runs on a read-only credential with enforced row and time limits.
- [ ] Every generated query is validated before execution and rejected by default when unrecognised.
- [ ] The executed query and its source tables are shown to permitted users, and every query is logged with its requester.
- [ ] Database content is treated as untrusted data and cannot redirect the model's behaviour.
- [ ] Access is gated by the app's permission system to operator-level roles.
- [ ] Model unavailability produces a clear message rather than any fallback execution.
- [ ] 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.