swe:test-gap-hunt

swe:test-gap-hunt is a skill for Claude Code from ckorhonen/swe-skills. It costs 121 tokens per session (2,110 once invoked), scanned A, original, MIT.

A focused review of a codebase's tests to find important behavior that is untested or tested weakly.

In plain words
What is it for?
Use it to find missing edge, error, branch, and boundary cases, strengthen fragile tests, and maintain a ranked testing backlog.
Why use it?
It helps improve confidence in the code without chasing coverage numbers or rewriting the project.

Skill for Claude Code

Written for Claude Code: shipped in a Claude Code plugin. Also seen: mentions subagents.

Part of the swe-skills plugin — 17 skills shipped together

Good fit Use it to find missing edge, error, branch, and boundary cases, strengthen fragile tests, and maintain a ranked testing backlog.

Compare 6 skills from other repositories ↓
Install with agentmods
npx agentmods add skills/ckorhonen/swe-skills/test-gap-hunt
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 ckorhonen/swe-skills --skill test-gap-hunt
Clone the repo
git clone --depth 1 https://github.com/ckorhonen/swe-skills

Made for: Claude Code.

Or install swe-skills, the plugin that ships this one along with the rest of its 17 skills.

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 swe:test-gap-hunt

README.md
[![agentmods](https://agentmods.dev/badge/skills/ckorhonen/swe-skills/test-gap-hunt/github.svg)](https://agentmods.dev/skills/ckorhonen/swe-skills/test-gap-hunt)
Your own site
<a href="https://agentmods.dev/skills/ckorhonen/swe-skills/test-gap-hunt"><img src="https://agentmods.dev/badge/skills/ckorhonen/swe-skills/test-gap-hunt/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 swe:test-gap-hunt

Your own site · 80×15
<a href="https://agentmods.dev/skills/ckorhonen/swe-skills/test-gap-hunt"><img src="https://agentmods.dev/badge/skills/ckorhonen/swe-skills/test-gap-hunt.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 121 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 2,110 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 $0.00121 $0.02110
Opus 5 $0.00060 $0.01055
Sonnet 5 $0.00024 $0.00422
Haiku 4.5 $0.00012 $0.00211

Measured 10d ago against content hash ba55d85f67b6, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-10, from the pricing page.

Security

Grade A, and why

swe:test-gap-hunt 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 10d 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.

skills/test-gap-hunt/SKILL.md · 307 lines

How it starts

The opening of the file, as written. The whole thing — 307 lines — stays where its author put it; the contents beside it link to each section on GitHub.

SWE Test Gap Hunt

What This Skill Does

Use this skill to run a bounded, evidence-led pass over a repository's tests.

The job is to:

  • Detect the existing test and coverage workflow
  • Rank the best test-improvement opportunities
  • Add or strengthen a small number of high-value tests
  • Improve weak test structure when it materially improves confidence or speed
  • Leave a ranked backlog for the next incremental pass

This skill is language agnostic. Reuse the repository's own tooling, file layout, and test conventions instead of forcing a new framework.

When To Use

Use this skill when the user wants to:

  • Improve coverage incrementally without broad rewrites
  • Find the most important uncovered or weakly tested code paths
  • Strengthen fragile, assertion-light, or over-mocked tests
  • Add missing edge, error, branch, or boundary cases
  • Run recurring or scheduled test-improvement passes over time

Do Not Use

Do not use this skill for:

  • First-time test framework selection or migration
  • Large production refactors done in the name of testability
  • Coverage-number campaigns with no quality bar
  • Pure performance profiling that is unrelated to test speed or test structure
  • Broad QA or bug hunting without a test-improvement goal

Inputs To Confirm

Confirm or infer:

  • Repository or package scope
  • Whether the user wants execution or report-only output
  • Runtime budget for validation and coverage commands
  • Any no-touch areas or flaky suites to avoid
  • Whether recent CI, coverage, or bug history is available

If the user does not specify a budget, default to a small incremental pass:

  • rank the workspace
  • improve the top 1-3 opportunities
  • stop after targeted validation

Parallelization Rule

Create one session per cleanly separated package, module, or service when the environment supports parallel agent work.

  • Run only on disjoint write surfaces
  • Cap concurrency to a level the repo can validate safely
  • Give each session a bounded target and explicit test files or directories
  • Have each session return raw evidence, changed files, and validation output
  • Keep prioritization, deduplication, and final validation in the parent session

Read the full file on GitHub · 307 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. 10d ago First seen · 307 lines · 121 tokens per session scan A ba55d85f67b6

Subscribe to this mod's changes

swe:test-gap-hunt is a skill published in the GitHub repository ckorhonen/swe-skills (3 stars, last pushed 1mo ago), licensed MIT. It adds 121 tokens to every session and 2,110 once invoked, about $0.0006 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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