chunk-testing-gaps

Run mutation testing on a local VCS codebase to identify surviving mutants.

84|40|Updated Feb 26, 2026

Search Tags:#observability #test coverage #risk assessment #mutation testing #git worktrees #CI validation #security auth

Ready to run

npx skills add https://github.com/CircleCI-Public/chunk-cli --skill chunk-testing-gaps

💬 Prompt for ChatGPT / Claude Chat▼

Please help me install this Agent Skill.
Skill: chunk-testing-gaps
Source: https://github.com/CircleCI-Public/chunk-cli/tree/main/skills/chunk-testing-gaps
Command: npx skills add https://github.com/CircleCI-Public/chunk-cli --skill chunk-testing-gaps

SYSTEM DOCUMENTATION & REQUIREMENTS

What problem does it solve?

It identifies where your test suite fails to detect realistic bugs by finding code mutations that still pass all validations, exposing gaps in coverage before they reach CI.

Core Features & Use Cases

Mutation gap discovery: Proposes security-, control-flow-, and validation-focused mutants across the codebase and numbers them for traceability.
Local + CI validation workflow: Kills mutants using static analysis and targeted tests, then confirms survivors via pushed worktree branches and CI results.
Production risk cross-reference: Attempts to map surviving mutants to real traffic using observability signals and then ranks outcomes by risk.

Quick Start

Ask the assistant to run chunk-testing-gaps on your current cloned repository to discover, validate, and risk-rank surviving mutants that indicate testing gaps.

Frequently Asked Questions about chunk-testing-gaps

High-intent search queries and answers about installing and using this skill.

FAQPage Schema

How do I find surviving test gaps using mutation testing in my local codebase?▼

Mutation testing identifies surviving test gaps by injecting mutants into auth, control-flow, and validation logic, then running local static checks and targeted tests to see which mutations pass undetected, exposing real coverage holes before CI.

How does mutation testing validate surviving mutants using git worktrees and CI?▼

Mutation testing validates survivors by creating git worktree branches for local static analysis and targeted tests, then pushing branches to remote CI pipelines to confirm whether mutants escape detection in your full validation workflow.

Can I use mutation testing to target security auth and input validation logic specifically?▼

Yes, mutation testing specifically targets authentication and authorization logic, input validation, state changes, and error-handling pathways while deliberately avoiding test and generated code to focus on security-critical execution paths.

What is the best way to cross-reference surviving mutants with production observability data?▼

The best approach maps surviving mutants to real traffic using observability signals, cross-referencing production data to determine which undetected mutations pose actual risk, then ranking outcomes by severity for prioritized reporting.

Does mutation testing for test coverage work with a staged local and remote workflow?▼

Yes, mutation testing uses a staged workflow combining local VCS codebase checks via git worktrees with remote CI verification, running static analysis locally first, then confirming surviving mutants through pushed branches and CI pipeline results.