sub-test-engineer

sub-test-engineer is a skill for Claude Code from brody-0125/my-claude-skills. It costs 93 tokens per session (6,519 once invoked), scanned A, original, MIT.

A testing workflow for Java, Kotlin, TypeScript, and Go backend projects. It examines the code, chooses testing methods, creates tests, and checks their effectiveness with coverage and mutation testing.

In plain words
What is it for?
Use it to plan and generate backend tests, including unit, property-based, API contract, and architecture tests where appropriate.
Why use it?
It helps find missing test cases and checks whether tests actually detect faulty code, instead of only counting whether lines ran.

Skill for Claude Code

Written for Claude Code: allowed-tools in frontmatter.

Part of the sub-test-engineer plugin — 1 skill shipped together

Good fit Use it to plan and generate backend tests, including unit, property-based, API contract, and architecture tests where appropriate.

Compare 6 skills from other repositories ↓
Install with agentmods
npx agentmods add skills/brody-0125/my-claude-skills/sub-test-engineer
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 brody-0125/my-claude-skills --skill sub-test-engineer
Clone the repo
git clone --depth 1 https://github.com/brody-0125/my-claude-skills

Made for: Claude Code.

Or install sub-test-engineer, the plugin that ships this one along with the rest of its 1 skill.

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 sub-test-engineer

README.md
[![agentmods](https://agentmods.dev/badge/skills/brody-0125/my-claude-skills/sub-test-engineer/github.svg)](https://agentmods.dev/skills/brody-0125/my-claude-skills/sub-test-engineer)
Your own site
<a href="https://agentmods.dev/skills/brody-0125/my-claude-skills/sub-test-engineer"><img src="https://agentmods.dev/badge/skills/brody-0125/my-claude-skills/sub-test-engineer/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 sub-test-engineer

Your own site · 80×15
<a href="https://agentmods.dev/skills/brody-0125/my-claude-skills/sub-test-engineer"><img src="https://agentmods.dev/badge/skills/brody-0125/my-claude-skills/sub-test-engineer.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 93 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 6,519 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 $0.00093 $0.06519
Opus 5 $0.00046 $0.03259
Sonnet 5 $0.00019 $0.01304
Haiku 4.5 $0.00009 $0.00652

Measured 11d ago against content hash d7090878f6ea, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-11, from the pricing page.

Security

Grade A, and why

sub-test-engineer 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 11d ago.

The scan reads SKILL.md. This mod also ships 11 executable files (scripts/agent-teams/aggregate-results.sh, scripts/agent-teams/detect-modules.sh, scripts/agent-teams/partition-targets.sh, …), listed below but not scanned — reading those needs a real analyzer, not pattern matching.

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/sub-test-engineer/skills/sub-test-engineer/SKILL.md · 606 lines

How it starts

The opening of the file, as written. The whole thing — 606 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Sub Test Engineer — Type-Aware Testing Workflow Agent

An agent that generates high-quality, convention-compliant tests through the Analyze → Strategize → Generate → Validate workflow, leveraging type system information for intelligent test case discovery.

Role

A testing-specialized workflow agent that generates comprehensive, type-aware tests for Java/Kotlin/TypeScript/Go backend projects. Unlike general coding agents that treat testing as a verification step, this agent treats test quality as the primary output. It automatically detects the project's test infrastructure, analyzes code-under-test complexity, selects appropriate testing techniques (unit, property-based, contract, architecture), and iterates until coverage and mutation-kill targets are met.

Core Principles

  1. Type-First Analysis: Extract type signatures, class hierarchies, sealed classes, enums, and validation annotations to drive test case discovery
  2. Multi-Technique Orchestration: Select the right testing technique for each code layer (property-based for domain logic, contract for APIs, architecture tests for structure)
  3. Coverage-Guided Iteration: Use line/branch coverage as feedback signal to generate targeted tests for uncovered code paths
  4. Test Quality over Quantity: Validate test effectiveness via mutation testing — a test suite that doesn't kill mutants is incomplete
  5. Project Pattern Conformance: Learn existing test patterns (naming, structure, fixtures, assertions) and generate tests that match the project style

Input Parsing and Ambiguity Resolution

Input Classification

Parse user input and classify into one of:

1. CLEAR target + mode     → "OrderService 테스트 생성. loop 3"
   → target=OrderService, mode=all-in-one, loop=3
   → Proceed to Phase 0

2. CLEAR phase command      → "analyze: PaymentService"
   → target=PaymentService, mode=step-by-step, phase=analyze
   → Jump to specified phase

3. CLEAR technique          → "property-test: OrderValidator"
   → target=OrderValidator, technique=property-based, mode=technique-specific
   → Skip Phase 2 (Strategize)

4. AMBIGUOUS target         → "테스트 해줘", "테스트 좀 추가해줘"
   → No target specified → trigger Target Resolution
   → Ask user or infer from git diff

5. SCOPE too broad          → "전체 프로젝트 테스트 생성"
   → Recommend narrowing scope to a package or module
   → Suggest top 3 packages by test debt

Read the full file on GitHub · 606 lines

Files

What ships with it

60 files 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. 11d ago First seen · 606 lines · 93 tokens per session scan A d7090878f6ea

Subscribe to this mod's changes

sub-test-engineer is a skill published in the GitHub repository brody-0125/my-claude-skills (2 stars, last pushed 6mo ago), licensed MIT. It adds 93 tokens to every session and 6,519 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 2026-08-31.

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