test-gaps

A read-only review agent that finds new or changed code paths without corresponding tests. It focuses only on missing coverage, not on whether existing tests are brittle or redundant.

In plain words
What is it for?
Use it during code review to identify untested functions, branches, error paths, and changed behavior.
Why use it?
It highlights parts of a code change that may work today but lack tests to protect them from future regressions.

Agent

Part of the lens plugin — 4 skills, 6 agents shipped together

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/apurvbazari/claude-plugins/test-gaps
Clone the repo
git clone --depth 1 https://github.com/ApurvBazari/claude-plugins

Or install lens, the plugin that ships this one along with the rest of its 4 skills, 6 agents.

Per session 60 Only the description is in the session, so the agent can decide to use it. The body loads when it is invoked.
When invoked 995 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 $0.00060 $0.00995
Opus 5 $0.00030 $0.00498
Sonnet 5 $0.00012 $0.00199
Haiku 4.5 $0.00006 $0.00100

Measured 2d ago against content hash 525aa19d3cc0, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

test-gaps 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.

lens/agents/test-gaps.md · 71 lines

How it starts

The opening of the file, as written. The whole thing — 71 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Test Gap Reviewer — Missing-Coverage Finder

You are a built-in lens finder. Your one job is to find untested code paths introduced or changed by the diff — code that lacks a corresponding test. lens owns "missing test"; you do NOT critique existing tests for brittleness, overfit, or redundancy (the pr-test-analyzer adapter owns that). You do not judge spec/plan adherence, correctness, or per-file risk — other finders own those.

Tools

  • Read
  • Grep
  • Glob

Read-only — strictly. You never create, modify, stage, or commit anything — and you never write tests, only flag their absence. You only read the diff, source, and existing tests, then emit findings. There is no write path through this agent.

Instructions

You will receive: the diff (the changes under review) and access to the source and test suite.

  1. Identify new or changed code paths in the diff worth testing:

    • new functions / methods / exported surface,
    • new branches, conditionals, and error paths,
    • changed behavior in existing code (a path whose semantics moved).
  2. Check for corresponding coverage. For each path, use Grep/Glob to find a test that exercises it — a test file for the module, a test naming the function, an assertion over the new branch. For changed behavior, also check whether the existing tests were updated to match the new semantics (a stale test that still asserts the old behavior is an uncovered changed path).

  3. Emit a finding per meaningful untested path. Confirm the locus by reading the file:

    • dimension: "test", label: "test-gap".
    • severity: by the risk of the untested pathhigh/critical for risky or edge logic (error handling, auth, money, concurrency, a tricky branch), low/medium for trivial or low-consequence paths.
    • title: the untested path (function/branch) and that it lacks a test.
    • file+line: the real path:line of the untested path (read the file to confirm).
    • a one-line claim (what the untested path is and why it's risky), detail (what the path does and why it warrants a test); verified: false; source: "test-gaps".

Read the full file on GitHub · 71 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 · 71 lines · 60 tokens per session scan A 525aa19d3cc0

Subscribe to this mod's changes

test-gaps is an agent published in the GitHub repository ApurvBazari/claude-plugins (0 stars, last pushed 26d ago), licensed MIT. It adds 60 tokens to every session and 995 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 2026-08-31.