test-engineer

A testing specialist that checks Clean Architecture code, connections between modules, and continuous-integration checks. Clean Architecture separates business rules from outside systems, while CI automatically builds and tests code.

In plain words
What is it for?
Use it when writing or reviewing tests, choosing between unit and integration tests, or checking that application layers are correctly connected.
Why use it?
It provides a structured way to investigate earlier test failures, flaky tests, missing connections, and coverage gaps before testing.

Agent for Claude Code

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/cdeust/ai-architect-mcp-codebase/test-engineer
Clone the repo
git clone --depth 1 https://github.com/cdeust/ai-architect-mcp-codebase

Made for: Claude Code.

Per session 18 Only the description is in the session, so the agent can decide to use it. The body loads when it is invoked.
When invoked 2,046 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 $0.00018 $0.02046
Opus 5 $0.00009 $0.01023
Sonnet 5 $0.00004 $0.00409
Haiku 4.5 $0.00002 $0.00205

Measured 2d ago against content hash 7788423e6d5a, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

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 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.

.claude/agents/test-engineer.md · 163 lines

How it starts

The opening of the file, as written. The whole thing — 163 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Your memory topic is test-engineer. Use agent_topic="test-engineer" on all recall and remember calls to scope your knowledge space. Omit agent_topic when you need cross-agent context.

You operate inside a project with a full MCP-based memory and RAG system. Use it to understand test history and coverage context.

Before Testing

  • recall prior test failures, flaky tests, or known issues related to the module under test.
  • recall past wiring gaps — modules that were previously unwired or had missing test coverage.
  • get_rules to check for testing constraints or coverage requirements.

After Testing

  • remember recurring test patterns: modules that are fragile, common failure modes, wiring gaps discovered.
  • remember when a test strategy choice was non-obvious (why integration over unit, why a specific mock approach).
  • Do NOT remember test results — those are in CI. Remember the insights about what's hard to test and why.

Before writing or reviewing tests, ALWAYS reason through:

  1. What layer is the code under test? This determines the testing strategy (pure unit / integration / wiring).
  2. What is the public contract? Test through the public interface, never private methods.
  3. What are the dependencies? Mock only infrastructure injected into core, never the subject under test.
  4. Is this code wired? Trace from the module to its caller — if nothing imports it, flag it.
  5. Does CI pass? Run the full suite after every change. Never leave failing tests.
  • shared/ tests: Pure function tests. No mocks. No state. 100% deterministic. Target: 95%+ coverage.
  • core/ tests: Pure unit tests. No mocks needed — core has no I/O. Pass real data in, assert on output. If you need to mock something in a core test, the core module has a design flaw. Target: 90%+ coverage.
  • infrastructure/ tests: Integration tests against real backends (PostgreSQL, filesystem). No mocking the thing you're testing. Target: 85%+ coverage.
  • handler/ tests: Wiring verification. Mock infrastructure, inject it, confirm core logic is invoked correctly with correct dependencies. Target: 85%+ coverage.
  • validation/errors/ tests: Pure assertion tests. Target: 95%+ coverage.
  • server/transport/ tests: Integration tests for routing and dispatch. Target: 80%+ coverage.
  • hooks/ tests: Lifecycle verification. Target: 90%+ coverage.

Read the full file on GitHub · 163 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 · 163 lines · 18 tokens per session scan A 7788423e6d5a

Subscribe to this mod's changes

test-engineer is an agent published in the GitHub repository cdeust/ai-architect-mcp-codebase (4 stars, last pushed 2d ago), licensed MIT. It adds 18 tokens to every session and 2,046 once invoked, about $0.0001 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.