mutagate

Mutation-testing hook for Claude Code, Codex, OpenCode, and Pi that mutates the code under each agent-written test and blocks completion until the tests kill at least 80% of the mutants

keyboardsamurai/mutagate · v0.9.0 · source 4927d40 · Development & Workflow

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Trust Score

Security

Surfaces

What is mutagate?

mutagate is a published development & workflow plugin for AI coding agents in the codex ecosystem, developed by keyboardsamurai and distributed through the HOL AI plugin registry. Mutation-testing hook for Claude Code, Codex, OpenCode, and Pi that mutates the code under each agent-written test and blocks completion until the tests kill at least 80% of the mutants

Canonical slug: keyboardsamurai/mutagate
Version: v0.9.0 · source 4927d40 · updated Oct 8, 2026
Open data: entity.json (JSON-LD)

Trust & Reputation

HOL Trust Score

Factor Analysis

Per-metric points (0–100 each) combined via a weighted average into the overall score.

Installability

64pts

Maintenance

80pts

MCP Posture

100pts

Plugin Security

59pts

Provenance

70pts

Publisher Quality

75pts

Registry Snapshot

Repository: https://github.com/keyboardsamurai/mutagate
Homepage: https://github.com/keyboardsamurai/mutagate
Canonical profile: https://hol.org/registry/plugins/keyboardsamurai%2Fmutagate
Publisher verification: No
Marketplace source: Unknown
Scanner: Broker fallback
Safety label: caution
Digest verified: Yes

1 bundled skill — copy or download SKILL.mdOpen skills

Trust & reputation

Trust & Reputation

HOL Trust Score

Factor Analysis

Per-metric points (0–100 each) combined via a weighted average into the overall score.

Installability

64pts

Maintenance

80pts

MCP Posture

100pts

Plugin Security

59pts

Provenance

70pts

Publisher Quality

75pts

Provenance

Plugin root: .
Source repo: https://github.com/keyboardsamurai/mutagate
Source commit: 4927d400fd10…
Publisher verified: No
Owner verified: Not owner verified

Continuous scanner CI not detected

This plugin remains listed. Its overall trust score is reduced by 10% because security checks are not maintained in the source repository's CI.

Optional: maintain the scanner in the source repository's CI to receive the full trust score. Listing does not require that change.

Verified badge not detected

Add the HOL verified badge to the repository README to score +2% trust. Plugin owners can open that pull request from Guard Plugins.

Security Posture

caution

Safety label

Security score

High findings

Provider: registry-broker-fallback
Grade: F · caution
Version: Unknown

cisco-skill-scanner: unknown

Findings

mediumpublishabilitypublishability.link.missing.websiteURL

websiteURL should be present for marketplace readiness.

mediumpublishabilitypublishability.link.missing.privacyPolicyURL

privacyPolicyURL should be present for marketplace readiness.

mediumpublishabilitypublishability.link.missing.termsOfServiceURL

termsOfServiceURL should be present for marketplace readiness.

lowoperational-securitysupply-chain.lockfile-missing

Repository snapshot does not include a lockfile.

infoskill-securityskill-scan.unavailable

Script permission declarations are required for scripts/: scripts/adapters/pi.ts, scripts/adapters/opencode.js, scripts/hooks.json, scripts/dotnet.cjs, scripts/doctor.cjs, scripts/glob.cjs, scripts/cache-jars.mjs, scripts/errors.cjs, scripts/inputs.cjs, scripts/kotlin-source.cjs, scripts/mutagate.mjs, scripts/install.cjs, scripts/mutmut-bridge.cjs, scripts/mutagate-hook.cjs

mutagate — Frequently asked questions

What is mutagate?: mutagate is an AI plugin in the HOL registry. Mutation-testing hook for Claude Code, Codex, OpenCode, and Pi that mutates the code under each agent-written test and blocks completion until the tests kill at least 80% of the mutants
How do I install mutagate?: Install mutagate in your harness: Source — https://github.com/keyboardsamurai/mutagate/releases; OpenCode — npx skills add keyboardsamurai/mutagate; Any agent — npx skills add keyboardsamurai/mutagate. Full step-by-step guidance is on the HOL plugin page.
How do I install mutagate in Source?: To install mutagate in Source, start with https://github.com/keyboardsamurai/mutagate/releases. The complete step-by-step install guide for Source is on the HOL plugin page.
How do I install mutagate in OpenCode?: To install mutagate in OpenCode, start with npx skills add keyboardsamurai/mutagate. The complete step-by-step install guide for OpenCode is on the HOL plugin page.
Is mutagate free?: Pricing for mutagate is published on its HOL plugin page when the maker schedules a launch.
Who publishes mutagate?: mutagate is published by keyboardsamurai and listed on HOL.
Is mutagate available now?: mutagate availability is listed on its HOL plugin page.

Install Guidance

Install in Source

Install from a native release archive or the assessed source revision.

Install guide

1
Download the release archive
Use a published GitHub release archive. The catalog version is the package version at the assessed commit.
shell
2
Follow the publisher install guide
https://github.com/keyboardsamurai/mutagate/blob/4927d400fd10055dadb56326d44f6ab9153d5fac/docs/INSTALL.md

Plugin Manifest

{
  "name": "mutagate",
  "version": "0.9.0",
  "description": "Mutation-testing hook for Claude Code, Codex, OpenCode, and Pi that mutates the code under each agent-written test and blocks completion until the tests kill at least 80% of the mutants",
  "repository": "https://github.com/keyboardsamurai/mutagate",
  "homepage": "https://github.com/keyboardsamurai/mutagate",
  "interface": {
    "displayName": "mutagate",
    "developerName": "keyboardsamurai",
    "category": "Development & Workflow"
  },
  "skills": "./",
  "holManifestOrigin": "synthesized",
  "registryIndexVersion": 5
}

Skills

1 SKILL.md file ship with this plugin. Preview, copy, or download each one, then install them with the Skills CLI.

skills-cli

mutagate
SKILL.md
Use mutation testing for test quality, inspect surviving mutants after writing tests, and check mutation scores before finishing tests.
Raw SKILL.md

File Inventory

.codex-plugin/plugin.json

plugin-manifest

537 bytes

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.github/dependabot.yml

file

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.github/ISSUE_TEMPLATE/bug.yml

file

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.github/ISSUE_TEMPLATE/config.yml

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.github/ISSUE_TEMPLATE/false-block.yml

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.github/ISSUE_TEMPLATE/runner-request.yml

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.github/PULL_REQUEST_TEMPLATE.md

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.github/workflows/release.yml

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AGENTS.md

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CHANGELOG.md

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CLAUDE.md

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CODE_OF_CONDUCT.md

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CONTEXT.md

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CONTRIBUTING.md

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docs/adr/0001-stryker-net-scratch-copy.md

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docs/adr/0002-agent-caused-errors-block-once.md

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docs/adr/0004-pending-and-final-unscored.md

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docs/adr/0005-gate-deadline-and-recovery-advice.md

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docs/adr/0006-pytest-collected-no-tests.md

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docs/adr/0007-waive-apply-refused-in-agent-sessions.md

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docs/adr/0008-usage-errors-exit-2.md

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docs/adr/0010-out-of-scope-boundaries.md

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docs/adr/0011-live-eval-local-two-runs-per-cell.md

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docs/adr/0012-uncovered-python-target-is-agent-caused.md

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docs/adr/0013-project-hooks-use-repo-relative-paths.md

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docs/adr/0014-skill-branch-distribution.md

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docs/adr/README.md

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docs/eval_suite_spec.md

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docs/eval_suite.md

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docs/go_csharp_runners.md

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docs/prd.md

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docs/releasing.md

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docs/validation.md

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package.json

file

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README.md

file

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README.md

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references/jars.json

file

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references/kotlin-junk.yaml

file

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references/result-schema.json

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references/survivor-playbook.md

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references/versions.json

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scripts/adapters/opencode.js

file

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scripts/adapters/pi.ts

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scripts/cache-jars.mjs

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scripts/doctor.cjs

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scripts/dotnet.cjs

file

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scripts/errors.cjs

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scripts/glob.cjs

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scripts/hooks.json

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scripts/inputs.cjs

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scripts/install.cjs

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scripts/kotlin-source.cjs

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scripts/mutagate-hook.cjs

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scripts/mutagate.mjs

file

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scripts/mutmut-bridge.cjs

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SECURITY.md

file

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SKILL.md

skill

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test/adapters/adapters.test.mjs

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test/clipped.mjs

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test/core.test.mjs

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test/corpus/coroutine-bytecode.txt

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test/corpus/generate.mjs

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test/corpus/README.md

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test/doctor.test.mjs

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test/driver.mjs

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test/drivers.mjs

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test/eval-run.test.mjs

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test/eval.test.mjs

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test/eval/checks.mjs

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test/eval/config.json

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test/eval/harnesses.mjs

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test/eval/tasks/go/reference/internal/matrix/service_test.go

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test/eval/tasks/kotlin/prompt.natural.md

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mutagate

What is mutagate?

Trust & Reputation

Factor Analysis

Registry Snapshot

Trust & reputation

Trust & Reputation

Factor Analysis

Provenance

Security Posture

Findings

mutagate — Frequently asked questions

Install Guidance

Install in Source

Plugin Manifest

Skills

File Inventory