tester-detective

tester-detective is a skill for Claude Code from MadAppGang/claude-code. It costs 50 tokens per session (4,361 once invoked), scanned A, original, MIT.

A test-analysis skill that examines which parts of a codebase are covered by tests. It uses code structure to connect functions with the tests that call them.

In plain words
What is it for?
It investigates test coverage, maps test infrastructure, finds tests for functions, and identifies likely coverage gaps.
Why use it?
It helps find untested code, weak coverage, missing edge cases, and tests that do not check meaningful behavior.

Skill for Claude Code

Written for Claude Code: allowed-tools in frontmatter. Also seen: names the AskUserQuestion tool.

Part of the code-analysis plugin — 12 skills, 2 commands, 1 agent shipped together

Good fit It investigates test coverage, maps test infrastructure, finds tests for functions, and identifies likely coverage gaps.

Compare 6 skills from other repositories ↓
Install with agentmods
npx agentmods add skills/madappgang/claude-code/tester-detective
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 MadAppGang/claude-code --skill tester-detective
Clone the repo
git clone --depth 1 https://github.com/MadAppGang/claude-code

Made for: Claude Code.

Or install code-analysis, the plugin that ships this one along with the rest of its 12 skills, 2 commands, 1 agent.

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 tester-detective

README.md
[![agentmods](https://agentmods.dev/badge/skills/madappgang/claude-code/tester-detective.svg)](https://agentmods.dev/skills/madappgang/claude-code/tester-detective)
Your own site
<a href="https://agentmods.dev/skills/madappgang/claude-code/tester-detective"><img src="https://agentmods.dev/badge/skills/madappgang/claude-code/tester-detective.svg" alt="Measured on agentmods" height="20"></a>
Per session 50 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 4,361 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 $0.00050 $0.04361
Opus 5 $0.00025 $0.02181
Sonnet 5 $0.00010 $0.00872
Haiku 4.5 $0.00005 $0.00436

Measured 8d ago against content hash 358e6109c5c1, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-08, from the pricing page.

Security

Grade A, and why

tester-detective 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 8d 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/code-analysis/skills/tester-detective/SKILL.md · 542 lines

How it starts

The opening of the file, as written. The whole thing — 542 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Tester Detective Skill

This skill uses claudemem's callers analysis for test coverage investigation.

Why Claudemem Works Better for Test Analysis

Task claudemem Native Tools
Find tests for function callers shows test files Grep *.test.ts
Coverage gaps No test callers = untested Manual checking
Test distribution Caller analysis Unknown
Test relationships AST direct mapping Text search

Primary commands:

  • claudemem --agent callers <name> - Find tests that call this function
  • claudemem --agent map "test spec" - Map test infrastructure

Tester Detective Skill

Version: 3.3.0 Role: QA Engineer / Test Specialist Purpose: Test coverage investigation using AST callers analysis and automated test-gaps detection

Role Context

You are investigating this codebase as a QA Engineer. Your focus is on:

  • Test coverage - What is tested vs. untested
  • Test callers - Which tests call each function
  • Edge cases - Boundary conditions in tests
  • Test quality - Are tests meaningful or superficial
  • Coverage gaps - Functions without test callers

Why callers is Perfect for Test Analysis

The callers command shows you:

  • Test callers = Tests appear as callers of the function
  • Coverage gaps = No test callers = untested code
  • Test distribution = Which tests cover which code
  • Direct relationships = Exact test-to-code mapping

Tester-Focused Commands (v0.3.0)

Find Tests for a Function

# Who calls this function? (tests will appear as callers)
claudemem --agent callers processPayment
# Filter: callers from test files are your tests
# src/services/payment.test.ts:45 → This is a test!

Map Test Infrastructure

# Find all test files
claudemem --agent map "test spec describe it"
# Find test utilities
claudemem --agent map "test helper mock stub"
# Find fixtures
claudemem --agent map "fixture factory builder"```

### Test Coverage Gaps (v0.4.0+ Required)

```bash

Read the full file on GitHub · 542 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. 8d ago First seen · 542 lines · 50 tokens per session scan A 358e6109c5c1

Subscribe to this mod's changes

tester-detective is a skill published in the GitHub repository MadAppGang/claude-code (279 stars, last pushed 5mo ago), licensed MIT. It adds 50 tokens to every session and 4,361 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 2026-08-30.

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