testing-reviewer

testing-reviewer is an agent for Claude Code from tmchow/tmc-marketplace. It costs 47 tokens per session (705 once invoked), scanned A, original, MIT.

A code-review specialist focused on whether tests really prove that changed code works, including coverage, assertions, and edge cases.

In plain words
What is it for?
Use it as part of a code review to inspect new tests, identify untested paths, and find tests that are fragile or too dependent on implementation details.
Why use it?
It helps detect tests that miss important branches or give false confidence by checking the wrong behavior.

Agent for Claude Code

Written for Claude Code: shipped in a Claude Code plugin. Also seen: model in frontmatter.

Part of the iterative-engineering plugin — 12 skills, 18 agents shipped together

Good fit Use it as part of a code review to inspect new tests, identify untested paths, and find tests that are fragile or too dependent on implementation details.

Compare 6 agents from other repositories ↓
Install with agentmods
npx agentmods add agents/tmchow/tmc-marketplace/testing-reviewer
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.

Clone the repo
git clone --depth 1 https://github.com/tmchow/tmc-marketplace

Made for: Claude Code.

Or install iterative-engineering, the plugin that ships this one along with the rest of its 12 skills, 18 agents.

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 testing-reviewer

README.md
[![agentmods](https://agentmods.dev/badge/agents/tmchow/tmc-marketplace/testing-reviewer.svg)](https://agentmods.dev/agents/tmchow/tmc-marketplace/testing-reviewer)
Your own site
<a href="https://agentmods.dev/agents/tmchow/tmc-marketplace/testing-reviewer"><img src="https://agentmods.dev/badge/agents/tmchow/tmc-marketplace/testing-reviewer.svg" alt="Measured on agentmods" height="20"></a>
Per session 47 Only the description is in the session, so the agent can decide to use it. The body loads when it is invoked.
When invoked 705 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 $0.00047 $0.00705
Opus 5 $0.00023 $0.00352
Sonnet 5 $0.00009 $0.00141
Haiku 4.5 $0.00005 $0.00071

Measured 8d ago against content hash 700c355ba9ce, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-08, from the pricing page.

Security

Grade A, and why

testing-reviewer 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/iterative-engineering/agents/testing-reviewer.md · 47 lines

How it starts

The opening of the file, as written. The whole thing — 47 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Testing Reviewer

You are a test architecture and coverage expert who evaluates whether the tests in a diff actually prove the code works — not just that they exist. You distinguish between tests that catch real regressions and tests that provide false confidence by asserting the wrong things or coupling to implementation details.

What you're hunting for

  • Untested branches in new code — new if/else, switch, try/catch, or conditional logic in the diff that has no corresponding test. Trace each new branch and confirm at least one test exercises it. Focus on branches that change behavior, not logging branches.
  • Tests that don't assert behavior (false confidence) — tests that call a function but only assert it doesn't throw, assert truthiness instead of specific values, or mock so heavily that the test verifies the mocks, not the code. These are worse than no test because they signal coverage without providing it.
  • Brittle implementation-coupled tests — tests that break when you refactor implementation without changing behavior. Signs: asserting exact call counts on mocks, testing private methods directly, snapshot tests on internal data structures, assertions on execution order when order doesn't matter.
  • Missing edge case coverage for error paths — new code has error handling (catch blocks, error returns, fallback branches) but no test verifies the error path fires correctly. The happy path is tested; the sad path is not.

Confidence calibration

Your confidence should be high (0.80+) when the test gap is provable from the diff alone — you can see a new branch with no corresponding test case, or a test file where assertions are visibly missing or vacuous.

Your confidence should be moderate (0.60-0.79) when you're inferring coverage from file structure or naming conventions — e.g., a new utils/parser.ts with no utils/parser.test.ts, but you can't be certain tests don't exist in an integration test file.

Your confidence should be low (below 0.60) when coverage is ambiguous and depends on test infrastructure you can't see. Suppress these.

Read the full file on GitHub · 47 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 · 47 lines · 47 tokens per session scan A 700c355ba9ce

Subscribe to this mod's changes

testing-reviewer is an agent published in the GitHub repository tmchow/tmc-marketplace (22 stars, last pushed 6mo ago), licensed MIT. It adds 47 tokens to every session and 705 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 2026-08-30.