qa-engineer-marvin

qa-engineer-marvin is an agent for coding agents from lklimek/claudius. It costs 65 tokens per session (2,332 once invoked), scanned A, original, GPL-3.0.

A code-review agent that checks whether implementation matches requirements by running tests and linters and examining edge cases, errors, and race conditions.

In plain words
What is it for?
Use it to validate completed code, run relevant checks, audit test coverage, and report quality or requirement problems.
Why use it?
It provides an independent check instead of relying on the author’s claims or review of their own changes. It can reveal missing test coverage and mismatches with the specification.

Agent

Part of the claudius plugin — 30 skills, 8 agents, 2 hooks shipped together

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.

agentmods
npx agentmods add agents/lklimek/claudius/qa-engineer-marvin
Clone the repo
git clone --depth 1 https://github.com/lklimek/claudius

Or install claudius, the plugin that ships this one along with the rest of its 30 skills, 8 agents, 2 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-marvin

README.md
[![agentmods](https://agentmods.dev/badge/agents/lklimek/claudius/qa-engineer-marvin.svg)](https://agentmods.dev/agents/lklimek/claudius/qa-engineer-marvin)
Your own site
<a href="https://agentmods.dev/agents/lklimek/claudius/qa-engineer-marvin"><img src="https://agentmods.dev/badge/agents/lklimek/claudius/qa-engineer-marvin.svg" alt="Measured on agentmods" height="20"></a>
Per session 65 Only the description is in the session, so the agent can decide to use it. The body loads when it is invoked.
When invoked 2,332 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. Scan, not verified.
Origin unknown 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 $0.00065 $0.02332
Opus 5 $0.00032 $0.01166
Sonnet 5 $0.00013 $0.00466
Haiku 4.5 $0.00006 $0.00233

Measured today against content hash ceeb116d7363, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

qa-engineer-marvin 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 today.

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-marvin.md · 120 lines

The source is not reproduced here

Licensed GPL-3.0

The repository is licensed GPL-3.0, which this catalogue does not treat as permission to reproduce the file. Read it at the source.

Read it on GitHub

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. today Changed · +4 lines ceeb116d7363
  2. 4d ago First seen · 116 lines · 65 tokens per session scan A f773c365278b

Subscribe to this mod's changes

qa-engineer-marvin is an agent published in the GitHub repository lklimek/claudius (1 stars, last pushed 4d ago), licensed GPL-3.0. It adds 65 tokens to every session and 2,332 once invoked, about $0.0003 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 2026-08-31.