test-runner

test-runner is a skill for Claude Code, Codex from JansenAnalytics/claudex. It costs 46 tokens per session (518 once invoked), scanned A, original, MIT.

A tool for running and interpreting automated tests in Jest, Vitest, pytest, Mocha, and tap projects. It can also produce coverage reports and look for flaky tests that change results between runs.

In plain words
What is it for?
Use it to run test suites, debug failures, measure coverage, find flaky tests, and set up test infrastructure.
Why use it?
It makes test execution more consistent across projects and helps explain failures, missing coverage, and unreliable tests.

Skill for Claude CodeCodex

Written for no agent in particular: nothing here depends on one.

Needs its repository: it runs a file that does not travel with it, so clone the repository first. The line is bash scripts/run-tests.sh [path].

Good fit Use it to run test suites, debug failures, measure coverage, find flaky tests, and set up test infrastructure.

Compare 6 skills 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/JansenAnalytics/claudex
agentmods
npx agentmods add skills/jansenanalytics/claudex/test-runner

Made for: Claude Code, Codex.

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 test-runner

README.md
[![agentmods](https://agentmods.dev/badge/skills/jansenanalytics/claudex/test-runner.svg)](https://agentmods.dev/skills/jansenanalytics/claudex/test-runner)
Your own site
<a href="https://agentmods.dev/skills/jansenanalytics/claudex/test-runner"><img src="https://agentmods.dev/badge/skills/jansenanalytics/claudex/test-runner.svg" alt="Measured on agentmods" height="20"></a>
Per session 46 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 518 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 $0.00046 $0.00518
Opus 5 $0.00023 $0.00259
Sonnet 5 $0.00009 $0.00104
Haiku 4.5 $0.00005 $0.00052

Measured 4d ago against content hash 6150ef9463a4, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-08, from the pricing page.

Security

Grade A, and why

test-runner 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 4d 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.

skills/test-runner/SKILL.md · 66 lines

What it actually says

test-runner

Run and interpret test suites across frameworks: Jest, Vitest, pytest, Mocha, tap. Use when: running tests, debugging test failures, generating coverage reports, writing test fixtures, or setting up test infrastructure for a project.

Usage

Run Tests

bash scripts/run-tests.sh [path]

Auto-detects framework from project files. Pass optional path to scope test run.

Coverage Report

bash scripts/coverage-report.sh [path]

Runs tests with coverage and summarizes results.

Detect Flaky Tests

bash scripts/flaky-detector.sh [path] [runs]

Runs test suite multiple times (default: 5) and reports tests with inconsistent results.

When to Use

  • Running tests in an unfamiliar project (auto-detects framework)
  • Debugging test failures — scripts parse output for actionable info
  • Checking coverage before a PR
  • Investigating flaky tests that pass/fail intermittently
  • Setting up test infrastructure for a new project

Framework Detection

Priority order:

  1. vitest.config.* → Vitest
  2. jest.config.* or "jest" in package.json → Jest
  3. .mocharc.* or "mocha" in package.json → Mocha
  4. "tap" in package.json → tap
  5. pytest.ini / pyproject.toml with [tool.pytest] / setup.cfg with [tool:pytest] → pytest
  6. Fallback: npm test if package.json exists, python -m pytest if .py test files exist

Resources

  • scripts/run-tests.sh — Universal test runner with framework detection
  • scripts/coverage-report.sh — Coverage reporter
  • scripts/flaky-detector.sh — Flaky test detector
  • references/framework-detection.md — Detection logic details
  • references/assertion-patterns.md — Common assertion patterns across frameworks
  • references/mocking-patterns.md — Mocking/stubbing patterns
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. 4d ago First seen · 66 lines · 46 tokens per session scan A 6150ef9463a4

Subscribe to this mod's changes

test-runner is a skill published in the GitHub repository JansenAnalytics/claudex (5 stars, last pushed 2mo ago), licensed MIT. It adds 46 tokens to every session and 518 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 2026-09-03.