# ADR-007 — API Design

## Status
Accepted for V1.

## Context
The frontend must be API-driven and Codex must not invent inconsistent response shapes.

## Decision
Use REST-style FastAPI endpoints with typed Pydantic schemas. Responses use stable envelopes for long-running jobs and direct resources for simple CRUD operations.

Errors use a common structure:

```json
{
  "error": {
    "code": "DATASET_NOT_FOUND",
    "message": "Dataset not found.",
    "details": {}
  }
}
```

## Consequences
Frontend API clients, tests, and docs stay consistent.

## Non-goals
No GraphQL in V1.