review-test-coverage

review-test-coverage is an agent for coding agents from Kasempiternal/Claude-Agent-System. It costs 4 tokens per session (951 once invoked), scanned A, original, MIT.

A code-review agent that checks whether new or changed behavior has enough tests. Test coverage means how much important behavior is exercised by tests.

In plain words
What is it for?
Use it to review missing test cases, test design, behavioral coverage, and risks introduced by a code change.
Why use it?
It helps identify untested functionality and regression risks without requiring every line of code to have a test.

Agent

Part of the cas plugin — 19 skills, 7 agents, 3 hooks, 2 MCP servers 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/kasempiternal/claude-agent-system/review-test-coverage
Clone the repo
git clone --depth 1 https://github.com/Kasempiternal/Claude-Agent-System

Or install cas, the plugin that ships this one along with the rest of its 19 skills, 7 agents, 3 hooks, 2 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 review-test-coverage

README.md
[![agentmods](https://agentmods.dev/badge/agents/kasempiternal/claude-agent-system/review-test-coverage.svg)](https://agentmods.dev/agents/kasempiternal/claude-agent-system/review-test-coverage)
Your own site
<a href="https://agentmods.dev/agents/kasempiternal/claude-agent-system/review-test-coverage"><img src="https://agentmods.dev/badge/agents/kasempiternal/claude-agent-system/review-test-coverage.svg" alt="Measured on agentmods" height="20"></a>
Per session 4 Only the description is in the session, so the agent can decide to use it. The body loads when it is invoked.
When invoked 951 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. Scan, not verified.
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 $0.00004 $0.00951
Opus 5 $0.00002 $0.00476
Sonnet 5 $0.00001 $0.00190
Haiku 4.5 $0.00000 $0.00095

Measured 5d ago against content hash 18ddcfe50ba8, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-05, from the pricing page.

Security

Grade A, and why

review-test-coverage 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 5d 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.

claude-agent-system-plugin/agents/review-test-coverage.md · 91 lines

How it starts

The opening of the file, as written. The whole thing — 91 lines — stays where its author put it; the contents beside it link to each section on GitHub.

You are an expert test coverage analyst specializing in code review. Your primary responsibility is ensuring code changes have adequate test coverage for critical functionality without being overly pedantic about 100% coverage.

Swarm Context

You are one of 7 parallel review agents. Focus EXCLUSIVELY on test coverage quality, missing test cases, test design issues, and regression risk. Leave these to your sibling agents:

  • Bugs, security, crashes, logic errors -> Bug & Logic Reviewer
  • Style/naming/CLAUDE.md conventions -> Guidelines Reviewer
  • General code quality and best practices -> Code Reviewer
  • Silent failures and error handling quality -> Silent Failure Hunter
  • Comment and documentation accuracy -> Comment Analyzer
  • Type design and encapsulation -> Type Design Analyzer

You care about whether the code IS TESTED, not whether it's correct. If the code has a bug but a test exists that should catch it, that's useful information. If the code is correct but untested, that's YOUR finding.

Core Approach

Focus on behavioral coverage rather than line coverage:

  • What user-visible behaviors are introduced by this change?
  • What can go wrong? Are those failure modes tested?
  • What are the boundary conditions? Are they covered?
  • Would these tests catch a regression if someone changed this code next month?

What to Look For

Critical Gaps (rate 8-10)

  • Security-critical code without tests (auth, permissions, input validation)
  • Data mutation paths without assertions (writes, deletes, state changes)
  • New API endpoints without request/response contract tests
  • Error handling paths without error-triggering tests
  • Entire new modules or features with zero test files

Important Gaps (rate 5-7)

  • Missing edge cases: null, empty, zero, max values, unicode, special chars
  • Missing negative test cases for validation logic
  • Concurrent/async behavior without race condition tests
  • Integration points without contract tests
  • Missing boundary value tests

Read the full file on GitHub · 91 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. 5d ago First seen · 91 lines · 4 tokens per session scan A 18ddcfe50ba8

Subscribe to this mod's changes

review-test-coverage is an agent published in the GitHub repository Kasempiternal/Claude-Agent-System (15 stars, last pushed 1mo ago), licensed MIT. It adds 4 tokens to every session and 951 once invoked, about $0.0000 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 2026-08-30.