Getting it into your agent
It runs from inside its repository, so the clone comes first — what it calls does not travel with the file alone.
git clone --depth 1 https://github.com/aj-geddes/useful-ai-promptsnpx agentmods add skills/aj-geddes/useful-ai-prompts/api-contract-testingWrote this? Show the measurements
A badge with what this costs and how it scanned, read live from this page, so it follows the numbers instead of freezing them. Markdown for a README, HTML for a documentation site or a project page.
[](https://agentmods.dev/skills/aj-geddes/useful-ai-prompts/api-contract-testing)<a href="https://agentmods.dev/skills/aj-geddes/useful-ai-prompts/api-contract-testing"><img src="https://agentmods.dev/badge/skills/aj-geddes/useful-ai-prompts/api-contract-testing/github.svg" alt="Measured on agentmods" height="20"></a>Or the 80×15 button, for a site that already has a row of RSS and ATOM ones. Only the verdict fits; the numbers stay here.
<a href="https://agentmods.dev/skills/aj-geddes/useful-ai-prompts/api-contract-testing"><img src="https://agentmods.dev/badge/skills/aj-geddes/useful-ai-prompts/api-contract-testing.svg" alt="Reviewed on agentmods" width="80" height="20"></a>- Socket pass
- Snyk pass
What it costs to keep this loaded
Counted locally with the o200k_base tokenizer, which is exact for GPT models; Claude uses its own tokenizer and its counts differ. Treat this as one consistent yardstick across the catalogue rather than a bill. Prices are per million input tokens.
| Model | Per session | Once invoked |
|---|---|---|
| Fable 5.1 | $0.00036 | $0.00710 |
| Opus 5 | $0.00018 | $0.00355 |
| Sonnet 5 | $0.00007 | $0.00142 |
| Haiku 4.5 | $0.00004 | $0.00071 |
Grade A, and why
api-contract-testing scanned grade A with 0 findings against 26 rules in 11 categories — prompt injection, anti-refusal, data exfiltration, privilege escalation, supply chain, agent snooping, system-prompt leakage, SSRF and excessive agency — measured 10d ago.
A static scan of the body, not an audit. Every finding is printed with the line that produced it so you can judge whether it matters here. A mod is markdown that instructs an agent; that is exactly why what it instructs is worth reading.
Nothing flagged
None of the 26 patterns this scan looks for appear in this file: no shell pipes, no recursive deletes, no credential paths, no hidden text, no instruction-override or anti-refusal phrasing, no agent-config snooping. That is not a guarantee, it is the absence of the things that are checkable.
How it starts
The opening of the file, as written. The whole thing — 103 lines — stays where its author put it; the contents beside it link to each section on GitHub.
API Contract Testing
Table of Contents
Overview
Contract testing verifies that APIs honor their contracts between consumers and providers. It ensures that service changes don't break dependent consumers without requiring full integration tests. Contract tests validate request/response formats, data types, and API behavior independently.
When to Use
- Testing microservices communication
- Preventing breaking API changes
- Validating API versioning
- Testing consumer-provider contracts
- Ensuring backward compatibility
- Validating OpenAPI/Swagger specifications
- Testing third-party API integrations
- Catching contract violations in CI
Quick Start
Minimal working example:
// tests/pact/user-service.pact.test.ts
import { PactV3, MatchersV3 } from "@pact-foundation/pact";
import { UserService } from "../../src/services/UserService";
const { like, eachLike, iso8601DateTimeWithMillis } = MatchersV3;
const provider = new PactV3({
consumer: "OrderService",
provider: "UserService",
port: 1234,
dir: "./pacts",
});
describe("User Service Contract", () => {
const userService = new UserService("http://localhost:1234");
describe("GET /users/:id", () => {
test("returns user when found", async () => {
await provider
.given("user with ID 123 exists")
.uponReceiving("a request for user 123")
.withRequest({
method: "GET",
path: "/users/123",
headers: {
// ... (see reference guides for full implementation)
Reference Guides
Detailed implementations in the references/ directory:
| Guide | Contents |
|---|---|
| Pact for Consumer-Driven Contracts | Pact for Consumer-Driven Contracts |
| OpenAPI Schema Validation | OpenAPI Schema Validation |
| JSON Schema Validation | JSON Schema Validation |
| REST Assured for Java | REST Assured for Java |
| Contract Testing with Postman | Contract Testing with Postman |
| Pact Broker Integration | Pact Broker Integration |
What ships with it
8 files beside SKILL.md in the same directory: the scripts, references and assets a skill reads on demand. Not counted in the per-session cost; read them before you install if any of them is executable.
- references/contract-testing-with-postman.md 1.1 KB
- references/json-schema-validation.md 3.4 KB
- references/openapi-schema-validation.md 1.3 KB
- references/pact-broker-integration.md 1.1 KB
- references/pact-for-consumer-driven-contracts.md 5.9 KB
- references/rest-assured-for-java.md 2.4 KB
- scripts/scaffold-tests.sh 574 B runs code
- templates/test-template.js 541 B runs code
What this file has done since we first saw it
Hashed on every crawl. A supply-chain change to an agent config is a question of when, not whether, so the history is kept rather than the latest state alone.
- 10d ago First seen · 103 lines · 36 tokens per session scan A d12944381add
api-contract-testing is a skill published in the GitHub repository aj-geddes/useful-ai-prompts (336 stars, last pushed 6mo ago), licensed MIT. It adds 36 tokens to every session and 710 once invoked, about $0.0002 per session on Opus 5. A static security scan graded it A with 0 findings. No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-30.
Other skills, from other repositories
server-side-calls
Call tRPC procedures directly from server code using t.createCallerFactory() and router.createCaller(context) for integration testing, internal server logic, and custom API endpoints. Catch TRPCError and extract HTTP status with getHTTPStatusCodeFromError(). Error handling via onError option.
mem0-test-integration
Verify a Mem0 integration produced by /mem0-integrate. Runs in the same workspace on the same branch (loose coupling) — installs dependencies, runs the repo's native test suite, then exercises a real end-to-end smoke flow against the user's API key. Produces a scorecard. TRIGGER when: user has just run /mem0-integrate…
prowler-test-api
Testing patterns for Prowler API: JSON:API, Celery tasks, RLS isolation, RBAC. Trigger: When writing tests for api/ (JSON:API requests/assertions, cross-tenant isolation, RBAC, Celery tasks, viewsets/serializers).
python-sdk
Implement or modify Python SDK behavior under python/composio, including tools, toolkits, sessions, auth configs, connected accounts, client integration, and shared Python models. Use for Python core runtime/API work; pair with python-testing and cross-sdk-parity when TypeScript must match.
convex-test
Generate convex-test tests for the app's Convex functions.
voiden
Create and edit Voiden .void files for API testing. Covers the .void file format and all enabled extension block types.