QA Sentinel Agent

QA Sentinel Agent is a skill for Claude Code from nxtg-ai/forge-plugin. It costs 108 tokens per session (1,911 once invoked), scanned A, original, MIT.

A quality-assurance guide for deciding what a software project should test and where each test belongs. It explains unit, integration, and end-to-end tests, where end-to-end tests check complete user flows, plus coverage and quality gates.

In plain words
What is it for?
Use it to design test plans, choose testing layers, review pull requests for missing tests, set quality gates, and assess whether coverage is meaningful.
Why use it?
It helps teams test the right behavior and avoid relying on flaky tests, excessive mocks, or coverage numbers that do not reflect real protection.

Skill for Claude Code

Written for Claude Code: allowed-tools in frontmatter.

Part of the nxtg-forge plugin — 27 skills, 23 commands, 33 agents, 3 hooks, 3 MCP servers shipped together

Good fit Use it to design test plans, choose testing layers, review pull requests for missing tests, set quality gates, and assess whether coverage is meaningful.

Compare 6 skills from other repositories ↓
Install with agentmods
npx agentmods add skills/nxtg-ai/forge-plugin/agent-qa-sentinel
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.

Any agent
npx skills add nxtg-ai/forge-plugin --skill agent-qa-sentinel
Clone the repo
git clone --depth 1 https://github.com/nxtg-ai/forge-plugin

Made for: Claude Code.

Or install nxtg-forge, the plugin that ships this one along with the rest of its 27 skills, 23 commands, 33 agents, 3 hooks, 3 MCP servers.

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 Sentinel Agent

README.md
[![agentmods](https://agentmods.dev/badge/skills/nxtg-ai/forge-plugin/agent-qa-sentinel/github.svg)](https://agentmods.dev/skills/nxtg-ai/forge-plugin/agent-qa-sentinel)
Your own site
<a href="https://agentmods.dev/skills/nxtg-ai/forge-plugin/agent-qa-sentinel"><img src="https://agentmods.dev/badge/skills/nxtg-ai/forge-plugin/agent-qa-sentinel/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 Sentinel Agent

Your own site · 80×15
<a href="https://agentmods.dev/skills/nxtg-ai/forge-plugin/agent-qa-sentinel"><img src="https://agentmods.dev/badge/skills/nxtg-ai/forge-plugin/agent-qa-sentinel.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 108 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 1,911 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 $0.00108 $0.01911
Opus 5 $0.00054 $0.00955
Sonnet 5 $0.00022 $0.00382
Haiku 4.5 $0.00011 $0.00191

Measured 6d ago against content hash eeade4951429, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-09, from the pricing page.

Security

Grade A, and why

QA Sentinel Agent 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 6d 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.

plugins/nxtg-forge/skills/agent-qa-sentinel/SKILL.md · 136 lines

How it starts

The opening of the file, as written. The whole thing — 136 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Agent: QA Sentinel

You are the QA Sentinel — the quality mind that designs how a codebase gets tested and enforces that the green signal means something. You partner with three distinct roles: the testing agent WRITES tests, crucible-detective AUDITS existing tests forensically, and you DESIGN the strategy — what to test, at which layer, why, and what gate blocks a merge.

Core responsibilities

  • Design test strategy per feature/layer before code is written.
  • Judge whether coverage is meaningful (catches bugs) vs hollow (inflated number).
  • Set and enforce quality gates; review PRs for test adequacy.
  • Diagnose systemic test-suite problems (flakiness, mock proliferation, dead tests).
  • Recommend advanced techniques: mutation, property-based, contract, visual-regression, load.

The layer decision (start here)

The single most common QA question is "what kind of test?". Answer with the pyramid, then push the assertion to the cheapest layer that still proves the behavior.

Layer Share Use for Do NOT use for
Unit ~70% pure functions, business logic, use cases, validators DB/network I/O, wiring
Integration ~20% repositories, real DB ops, external-API adapters — no mocks pure domain logic
E2E ~10% critical user flows (signup, login, checkout) edge cases, error branches

Worked examples for each layer (async pytest, real-DB integration, Playwright E2E, a full payment-critical-path suite, GOOD/BAD contrasts) live in reference/test-examples.md.

The coverage-is-real question

A coverage number is a lead, not proof. Before trusting "85%":

  1. Is it line coverage or a file ratio? This plugin's forge_get_code_metrics reports real Istanbul/c8 line coverage ONLY when coverage/coverage-summary.json exists; with no report it falls back to testFileRatio (test-files ÷ source-files — a proxy that says nothing about which lines run). "85%" from a file ratio is not coverage. (Source: servers/governance-mcp/tools.mjs, testFileRatio vs testCoverage.)
  2. Do the tests assert on values, or just that code ran without throwing? A test with no meaningful assert (or a toBeDefined() / typeof x === 'string' shell) is hollow.
  3. Any omit / coveragePathIgnorePatterns hiding the untested code? That is coverage gaming — see the CRUCIBLE fraud patterns.

Read the full file on GitHub · 136 lines

Files

What ships with it

1 file 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.

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. 6d ago First seen · 136 lines · 108 tokens per session scan A eeade4951429

Subscribe to this mod's changes

QA Sentinel Agent is a skill published in the GitHub repository nxtg-ai/forge-plugin (5 stars, last pushed 3d ago), licensed MIT. It adds 108 tokens to every session and 1,911 once invoked, about $0.0005 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.

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