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.
npx skills add Claritune/mutantx --skill mx-generategit clone --depth 1 https://github.com/Claritune/mutantxWrote 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.
[](https://agentmods.dev/skills/claritune/mutantx/mx-generate)<a href="https://agentmods.dev/skills/claritune/mutantx/mx-generate"><img src="https://agentmods.dev/badge/skills/claritune/mutantx/mx-generate/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.
<a href="https://agentmods.dev/skills/claritune/mutantx/mx-generate"><img src="https://agentmods.dev/badge/skills/claritune/mutantx/mx-generate.svg" alt="Reviewed on agentmods" width="80" height="20"></a>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.
| Model | Per session | Once invoked |
|---|---|---|
| Fable 5.1 | $0.00020 | $0.01749 |
| Opus 5.5 | $0.00008 | $0.00700 |
| Sonnet 5.5 | $0.00004 | $0.00350 |
| Haiku 4.5 | $0.00002 | $0.00175 |
Grade A, and why
mx-generate 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 2mo 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.
How it starts
The opening of the file, as written. The whole thing — 170 lines — stays where its author put it; the contents beside it link to each section on GitHub.
MutantX — Phase 2: Mutant Generation
You are the mutant generation phase of a mutation testing engine. Your job is to read source files and generate realistic code mutations as unified diff patches.
Key principle: You are NOT an AST-based tool applying blind syntactic transformations. You understand the code semantically. Generate mutations that represent realistic bugs a developer might actually introduce — off-by-one errors, wrong operator choices, forgotten edge cases, swapped arguments, missing null checks. Avoid trivial or equivalent mutations.
Input
Read .mutants/detect.json for project configuration (language, test command, source files). If the file doesn't exist and files is not provided, tell the user to run /mx-detect first.
Check for Cached Mutants
Look for .mutants/manifest.json in the project root.
If .mutants/manifest.json does not exist or regen is "true", proceed with full generation.
If the manifest exists AND regen is not "true", do a per-file staleness check:
- Read the manifest. It contains a
file_hashesmap of{ "path": "<sha256>" }for every source file that was mutated. - For each source file in scope, compute its current content hash:
sha256sum <file> | cut -d' ' -f1. - Compare against the stored hash:
- Hash matches → the file hasn't changed. Keep its existing mutants and skip regeneration for this file.
- Hash differs → the file has changed. Delete its old patches, remove its mutants from the manifest, and regenerate mutants for this file.
- File is new (not in
file_hashes) → generate mutants for it. - File was deleted (in
file_hashesbut no longer exists) → remove its mutants and patches.
- Also run
git apply --checkon each kept patch to verify it still applies cleanly. If a patch no longer applies, discard that mutant and regenerate.
Report the cache status to the user:
Cached: 8 mutants for 3 unchanged files
Regenerating: 2 files changed (src/billing.ts, src/auth.ts)
New: 1 file added (src/payments.ts)
Removed: 1 file deleted (src/legacy.ts)
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.
- 2mo ago First seen · 170 lines · 20 tokens per session scan A a451d4b47871
mx-generate is a skill published in the GitHub repository Claritune/mutantx (2 stars, last pushed yesterday), licensed MIT. It adds 20 tokens to every session and 1,749 once invoked, about $0.0001 per session on Opus 5.5. 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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