api-coverage-planner

api-coverage-planner is an agent for Claude Code from ErkanBarin/playwright-agent-mcp-starter. It costs 21 tokens per session (512 once invoked), scanned A, original, MIT.

An agent that plans API tests from a list of endpoints or an OpenAPI specification, which is a machine-readable description of an API. It uses Playwright's request-testing support and places tests in tests/api/.

In plain words
What is it for?
Planning or generating tests for successful responses, validation errors, authentication, permissions, not-found cases, and unusual or large inputs.
Why use it?
It turns an endpoint list into a consistent coverage plan, including normal requests, invalid input, access controls, missing resources, and boundary cases.

Agent for Claude Code

Written for Claude Code: a Claude Code subagent (agents/*.md). Also seen: model in frontmatter.

Needs its repository: it reads a path above its own folder, which exists only inside the repository. The line is import { test, expect } from '../fixtures/base.fixture';.

Good fit Planning or generating tests for successful responses, validation errors, authentication, permissions, not-found cases, and unusual or large inputs.

Compare 6 agents from other repositories ↓
Install

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.

Clone the repo
git clone --depth 1 https://github.com/ErkanBarin/playwright-agent-mcp-starter
agentmods
npx agentmods add agents/erkanbarin/playwright-agent-mcp-starter/api-coverage-planner

Made for: Claude Code.

Wrote 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.

agentmods badge for api-coverage-planner

README.md
[![agentmods](https://agentmods.dev/badge/agents/erkanbarin/playwright-agent-mcp-starter/api-coverage-planner/github.svg)](https://agentmods.dev/agents/erkanbarin/playwright-agent-mcp-starter/api-coverage-planner)
Your own site
<a href="https://agentmods.dev/agents/erkanbarin/playwright-agent-mcp-starter/api-coverage-planner"><img src="https://agentmods.dev/badge/agents/erkanbarin/playwright-agent-mcp-starter/api-coverage-planner/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.

agentmods 80×15 button for api-coverage-planner

Your own site · 80×15
<a href="https://agentmods.dev/agents/erkanbarin/playwright-agent-mcp-starter/api-coverage-planner"><img src="https://agentmods.dev/badge/agents/erkanbarin/playwright-agent-mcp-starter/api-coverage-planner.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 21 Only the description is in the session, so the agent can decide to use it. The body loads when it is invoked.
When invoked 512 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. A grade says what 26 rules found in the file — not that it is safe.
Origin original No closer match found in the catalogue.
Token cost

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.

ModelPer sessionOnce invoked
Fable 5.1 $0.00021 $0.00512
Opus 5.5 $0.00008 $0.00205
Sonnet 5.5 $0.00004 $0.00102
Haiku 4.5 $0.00002 $0.00051

Measured 2mo ago against content hash 21cb55e8644a, method: parsed. Prices are Anthropic first-party input rates as of 2026-10-07, from the pricing page.

Security

Grade A, and why

api-coverage-planner 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 2mo 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.

ai/agents/api-coverage-planner.md · 61 lines

How it starts

The opening of the file, as written. The whole thing — 61 lines — stays where its author put it; the contents beside it link to each section on GitHub.

API Coverage Planner

You plan and generate API test coverage using Playwright's built-in APIRequestContext. Tests go in tests/api/.

Coverage Matrix

For each endpoint, plan tests covering:

Category Description Example
Happy Path Standard success response GET /users → 200
Validation Invalid input handling POST /users with empty body → 400
Authentication Auth requirements GET /users without token → 401
Authorization Permission checks DELETE /admin/users as regular user → 403
Not Found Missing resources GET /users/99999 → 404
Edge Cases Boundaries, large payloads GET /users?limit=10000

Test Generation Pattern

import { test, expect } from '../fixtures/base.fixture';

test.describe('GET /api/resource @api', () => {
  test('returns 200 with valid request', async ({ apiContext }) => {
    const response = await apiContext.get('/api/resource');
    expect(response.status()).toBe(200);
    const body = await response.json();
    expect(body).toHaveProperty('data');
  });

  test('returns 401 without auth token', async ({ request }) => {
    const response = await request.get('/api/resource');
    expect(response.status()).toBe(401);
  });

  test('returns 404 for nonexistent resource', async ({ apiContext }) => {
    const response = await apiContext.get('/api/resource/nonexistent-id');
    expect(response.status()).toBe(404);
  });
});

Process

  1. Discover endpoints — Read OpenAPI spec, Postman collection, or codebase routes.
  2. Map existing coverage — Grep for endpoint paths in tests/api/.
  3. Identify gaps — Find endpoints with missing status code coverage.
  4. Generate test skeletons — Create test files using the fixture pattern.
  5. Prioritize — Data mutations (POST/PUT/DELETE) and auth endpoints first.

Output

Produce a coverage matrix and test file(s) ready to fill in with real endpoint details.

Read the full file on GitHub · 61 lines

Changes

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.

  1. 2mo ago First seen · 61 lines · 21 tokens per session scan A 21cb55e8644a

Subscribe to this mod's changes

api-coverage-planner is an agent published in the GitHub repository ErkanBarin/playwright-agent-mcp-starter (43 stars, last pushed 7mo ago), licensed MIT. It adds 21 tokens to every session and 512 once invoked, about $0.0001 per session on Opus 5.5. 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.

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