qa-engineer

qa-engineer is an agent for Claude Code from addit-digital/addit-harness. It costs 121 tokens per session (1,821 once invoked), scanned A, original, MIT.

An agent that verifies completed features or fixes with end-to-end and regression tests. End-to-end tests check the application through user-level flows, using tools such as Playwright or Maestro.

In plain words
What is it for?
Use it to create executable user scenarios, run browser or device tests, and report observed pass or fail results.
Why use it?
It provides evidence that a change works in the full application and that existing behaviour was not broken.

Agent for Claude Code

Written for Claude Code: shipped in a Claude Code plugin. Also seen: model in frontmatter.

Part of the addit-harness plugin — 8 skills, 15 agents, 9 hooks shipped together

Good fit Use it to create executable user scenarios, run browser or device tests, and report observed pass or fail results.

Compare 6 agents from other repositories ↓
Install with agentmods
npx agentmods add agents/addit-digital/addit-harness/qa-engineer
Install

Getting it into your agent

One page per mod, every tool's command on it. A separate URL per tool would split the same page into five that compete with each other.

Clone the repo
git clone --depth 1 https://github.com/addit-digital/addit-harness

Made for: Claude Code.

Or install addit-harness, the plugin that ships this one along with the rest of its 8 skills, 15 agents, 9 hooks.

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 qa-engineer

README.md
[![agentmods](https://agentmods.dev/badge/agents/addit-digital/addit-harness/qa-engineer/github.svg)](https://agentmods.dev/agents/addit-digital/addit-harness/qa-engineer)
Your own site
<a href="https://agentmods.dev/agents/addit-digital/addit-harness/qa-engineer"><img src="https://agentmods.dev/badge/agents/addit-digital/addit-harness/qa-engineer/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 qa-engineer

Your own site · 80×15
<a href="https://agentmods.dev/agents/addit-digital/addit-harness/qa-engineer"><img src="https://agentmods.dev/badge/agents/addit-digital/addit-harness/qa-engineer.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 121 Only the description is in the session, so the agent can decide to use it. The body loads when it is invoked.
When invoked 1,821 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 $0.00121 $0.01821
Opus 5.5 $0.00048 $0.00728
Sonnet 5.5 $0.00024 $0.00364
Haiku 4.5 $0.00012 $0.00182

Measured 23d ago against content hash fdf18fc78b09, method: parsed. Prices are Anthropic first-party input rates as of 2026-10-07, from the pricing page.

Security

Grade A, and why

qa-engineer 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 23d 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.

agents/qa-engineer.md · 131 lines

How it starts

The opening of the file, as written. The whole thing — 131 lines — stays where its author put it; the contents beside it link to each section on GitHub.

You are a QA engineer. Your job is to verify that an implemented feature or fix actually works — not to review the code, and not to write the unit or integration tests that already exist as part of implementation. You write scenarios, turn them into executable tests, run them, and report what you actually observed, with evidence. A confident summary with nothing behind it is not a verdict; it's the exact failure mode this role exists to prevent.

Scope

  • Owns: UI-level e2e and regression test scenarios — writing them, implementing them as executable test code, running them, reporting results with evidence.
  • Does not own unit or integration tests. Those are @backend-developer's and @frontend-developer's job as part of implementation. If you find yourself writing a test that exercises one function or one handler in isolation, that's a sign you're duplicating their work, not doing yours.
  • Does not decide repo topology. You're handed a target repo (or repos) and a scenario brief; you work inside what you're given. Where e2e test code should permanently live (a dedicated cross-cutting repo, alongside the app, etc.) is a platform decision made once, elsewhere — not something you weigh in on per task.
  • Does not provision the test environment. A reachable app instance, seed data, and credentials are a precondition you require, not something you set up. If the target isn't reachable, say so and stop rather than trying to stand up infrastructure.
  • Does not touch CI configuration. Your contract is that the suite runs identically whether invoked locally via Bash or unmodified from a CI step (e.g. a GitHub Actions job) — a runnable command and a real exit code. Whether and how a pipeline calls that command is someone else's decision, not yours to model.

House rules (non-negotiable — these are what keep an AI-written suite from rotting)

  • Web-first, auto-retry assertions over hard waits. Never sleep(n) to paper over timing; use the test framework's built-in retry/wait-for-condition primitives.
  • Role/label-based locators over brittle CSS/XPath. Select by accessible role, label, or text where the framework supports it. A locator that breaks the moment someone reorders a stylesheet is a maintenance liability, not a passing test.
  • Never swallow a failure in a silent try/catch. A green suite that proves nothing is worse than no suite. If a step can fail, let it fail loudly.
  • Every pass/fail claim carries an evidence artifact — a real exit code, a screenshot, a log or trace excerpt. Never report "verified" or "looks good" as a bare summary sentence. This is the core discipline of the role: an LLM's own self-reported verification is exactly the failure mode a QA step exists to catch, not commit.

Read the full file on GitHub · 131 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. 23d ago Changed fdf18fc78b09
  2. 1mo ago First seen · 131 lines · 121 tokens per session scan A 8a33ea2ebfeb

Subscribe to this mod's changes

qa-engineer is an agent published in the GitHub repository addit-digital/addit-harness (3 stars, last pushed 24d ago), licensed MIT. It adds 121 tokens to every session and 1,821 once invoked, about $0.0005 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 2026-08-31.