3.3What to Feed and How

Source	How to Feed	Why It Matters
OpenAPI/Swagger spec	Paste the relevant endpoint JSON/YAML directly	Exact field names, types, constraints -- eliminates guesswork
User story + AC	Copy from Jira/Linear verbatim	Preserves original intent, edge cases mentioned in comments
Existing test file	Paste 2-3 representative tests as "style guide"	AI matches naming, structure, assertion style, fixtures
Database schema	Paste CREATE TABLE statements	Reveals constraints AI can test (NOT NULL, UNIQUE, FK, CHECK)
Error code documentation	Paste the error catalogue	AI generates tests triggering each documented error
UI mockup/Figma	Describe the layout or use screenshot + vision model	Generates accessibility and layout tests
CI configuration	Paste relevant test commands	AI understands how tests will be run (parallel, coverage flags)

Feeding an OpenAPI Schema

Here is the OpenAPI schema for the endpoint under test:

```yaml
paths:
  /api/v2/orders:
    post:
      summary: Create a new order
      security:
        - BearerAuth: [customer]
      requestBody:
        required: true
        content:
          application/json:
            schema:
              $ref: '#/components/schemas/CreateOrder'
      responses:
        '201':
          description: Order created
        '400':
          description: Validation error
        '401':
          description: Unauthorized
        '409':
          description: Duplicate order (idempotency key conflict)

components:
  schemas:
    CreateOrder:
      type: object
      required: [items, shipping_address, idempotency_key]
      properties:
        items:
          type: array
          minItems: 1
          maxItems: 50
          items:
            type: object
            required: [product_id, quantity]
            properties:
              product_id:
                type: string
                format: uuid
              quantity:
                type: integer
                minimum: 1
                maximum: 100
        shipping_address:
          $ref: '#/components/schemas/Address'
        idempotency_key:
          type: string
          format: uuid
        coupon_code:
          type: string
          pattern: "^[A-Z0-9]{8}$"

Notice that every constraint in the schema (minItems, maxItems, minimum, maximum, pattern, format) is a test case waiting to be generated. The LLM sees these constraints and produces boundary value tests automatically.

Feeding Existing Tests as a Style Guide

Here are two existing tests from our codebase. Match their style exactly:

```python
class TestOrderCreation:
    """Tests for POST /api/v2/orders endpoint."""

    def test_should_create_order_when_valid_payload(
        self, api_client, auth_headers, product_factory
    ):
        # Arrange
        product = product_factory.create()
        payload = {
            "items": [{"product_id": str(product.id), "quantity": 2}],
            "shipping_address": VALID_ADDRESS,
            "idempotency_key": str(uuid4()),
        }

        # Act
        response = api_client.post(
            "/api/v2/orders", json=payload, headers=auth_headers
        )

        # Assert
        assert response.status_code == 201
        order = response.json()
        assert order["status"] == "pending"
        assert len(order["items"]) == 1
        assert order["items"][0]["quantity"] == 2

    def test_should_reject_order_when_empty_items_list(
        self, api_client, auth_headers
    ):
        # Arrange
        payload = {
            "items": [],
            "shipping_address": VALID_ADDRESS,
            "idempotency_key": str(uuid4()),
        }

        # Act
        response = api_client.post(
            "/api/v2/orders", json=payload, headers=auth_headers
        )

        # Assert
        assert response.status_code == 400
        assert "items" in response.json()["detail"].lower()

By showing two tests -- one happy path, one validation error -- the AI learns:

• Class structure with docstrings
• Fixture-based dependency injection (api_client, auth_headers, product_factory)
• Naming convention: test_should_X_when_Y
• Comment markers for Arrange/Act/Assert
• Assertion style (status code + specific field checks)
• Use of VALID_ADDRESS constant and uuid4()