mockd: Cursor rule for Cursor

mockd Rules for Cursor

Copy this file to .cursor/rules/mockd.md in your project root.

mockd Overview

mockd is a multi-protocol API mock server (HTTP, GraphQL, gRPC, WebSocket, MQTT, SSE, SOAP). It runs as a single binary with an admin API.

MCP Integration

mockd has an MCP server with 18 tools. Configure in .cursor/mcp.json:

{
  "mcpServers": {
    "mockd": {
      "command": "mockd",
      "args": ["mcp"]
    }
  }
}

The MCP server auto-starts a background daemon if no mockd server is running.

Ports

• Mock server: 4280 (never use 8080)
• Admin API: 4290 (never use 8081)

Common Patterns

Create a mock endpoint

mockd add http --path /api/users --status 200 --body '{"users":[]}'

Create CRUD endpoints (auto-generates GET, POST, PUT, DELETE)

mockd add http --path /api/users --stateful

Start with a config file

mockd start -c mocks.yaml

Verify mocks in CI

mockd verify check <mock-id> --exactly 3 || exit 1

Inject chaos for resilience testing

mockd chaos apply flaky    # 30% errors
mockd chaos apply offline  # 100% 503
mockd chaos disable

Config Format

mocks:
  - id: get-users
    type: http
    http:
      matcher:
        method: GET
        path: /api/users
      response:
        statusCode: 200
        body: '[{"id":"{{uuid}}","name":"{{faker.name}}"}]'

Template Functions

• {{uuid}} — UUID v4
• {{faker.name}}, {{faker.email}}, {{faker.phone}} — Identity
• {{faker.creditCard}}, {{faker.iban}}, {{faker.price}} — Finance
• {{now}}, {{timestamp}} — Time
• {{request.Method}}, {{request.Path}} — Echo request
• {{random.Int 1 100}} — Random numbers
• {{faker.words(5)}} — Parameterized

Tables + Extend (Stateful Config)

The recommended way to add stateful CRUD to imported API specs in config files:

version: "1.0"
imports:
  - path: api-spec.yaml
    as: api
tables:
  - name: users
    idField: id
extend:
  - { mock: api.ListUsers, table: users, action: list }
  - { mock: api.CreateUser, table: users, action: create }
  - { mock: api.GetUser, table: users, action: get }