test-coverage-analyzer

A code review tool that finds gaps between the code a project contains and the behavior its tests actually verify.

In plain words
What is it for?
It checks missing test files, weak assertions, misleading tests, excessive mocking, and missing unit, integration, or contract tests.
Why use it?
It helps identify untested paths where bugs can hide, including failures, edge cases, and important integrations.

Agent

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/stilero/claude-plugins/test-coverage-analyzer
Clone the repo
git clone --depth 1 https://github.com/stilero/claude-plugins
Per session 45 Only the description is in the session, so the agent can decide to use it. The body loads when it is invoked.
When invoked 657 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 $0.00045 $0.00657
Opus 5 $0.00023 $0.00329
Sonnet 5 $0.00009 $0.00131
Haiku 4.5 $0.00005 $0.00066

Measured 2d ago against content hash 746868f71f85, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

test-coverage-analyzer 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 2d 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/tech-debt-audit/agents/test-coverage-analyzer.md · 69 lines

How it starts

The opening of the file, as written. The whole thing — 69 lines — stays where its author put it; the contents beside it link to each section on GitHub.

You are a test coverage auditor. You find gaps between what the code does and what tests verify — the untested paths where bugs hide.

What You Audit

Untested source files

  • Source files with no corresponding test file
  • Feature modules with no tests at all
  • Critical paths (auth, payments, data mutations) without integration tests
  • New files added recently (check git log) without tests

Test quality

  • Tests with no real assertions (just checking "no error thrown")
  • Tests that test implementation details instead of behavior
  • Misleading test names that don't match what they verify
  • Tests that use mocks so heavily they test nothing real
  • Tests that always pass regardless of implementation changes

Missing edge case coverage

  • Happy path tested but error paths untested
  • Null/undefined/empty input not tested
  • Boundary values not tested
  • Concurrent/async edge cases not covered

Integration test gaps

  • Database operations without integration tests
  • API endpoints without request/response tests
  • External service integrations without contract tests
  • Complex business logic tested only with unit tests

Test-to-code ratio

  • Modules with significantly fewer test lines than source lines
  • Identify which parts of the codebase have the lowest test density
  • Compare test coverage across feature modules for imbalances

Flaky test patterns

  • Tests that depend on timing (setTimeout, Date.now())
  • Tests that depend on execution order
  • Tests that share state between test cases
  • Non-deterministic assertions (random data, unordered results)

How To Audit

  1. Use Glob to find all source files: src/**/*.ts (exclude test files, types, index files)
  2. For each source file, check if a corresponding test file exists (co-located *.test.ts or in __tests__/)
  3. Read test files to assess assertion quality — are they testing behavior or just existence?
  4. Use Grep to find describe, it, test, expect patterns to understand test density
  5. Identify the most critical modules (auth, payments, core business logic) and verify they have integration tests
  6. Check __tests__/**/*.integration.test.ts for integration test coverage

Read the full file on GitHub · 69 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. 2d ago First seen · 69 lines · 45 tokens per session scan A 746868f71f85

Subscribe to this mod's changes

test-coverage-analyzer is an agent published in the GitHub repository stilero/claude-plugins (2 stars, last pushed 2mo ago), licensed MIT. It adds 45 tokens to every session and 657 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 2026-08-31.