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 agentmods add skills/greglas75/zuvo/mutation-testnpx skills add greglas75/zuvo --skill mutation-testgit clone --depth 1 https://github.com/greglas75/zuvoWhat 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 | $0.00190 | $0.19776 |
| Opus 5 | $0.00095 | $0.09888 |
| Sonnet 5 | $0.00038 | $0.03955 |
| Haiku 4.5 | $0.00019 | $0.01978 |
Grade A, and why
mutation-test 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.
How it starts
The opening of the file, as written. The whole thing — 1,370 lines — stays where its author put it; the contents beside it link to each section on GitHub.
zuvo:mutation-test -- LLM-Guided Mutation Testing
Intelligent mutation testing that targets meaningful behavioral gaps rather than random code changes. For each production file, the LLM generates mutations in 7 categories (boundary, logic, null, error, state, async, security), runs only the tests that cover that file, and closes the gaps it finds: every survivor is triaged as a real gap or an equivalent mutant, and each real gap gets the missing assertion added and re-probed in the same run.
Scope: Production files that have associated test files. Measures how well existing tests detect real behavioral changes.
When to use: After writing tests, before releases, when mutation score is unknown, when test suite feels shallow despite high line coverage.
Out of scope: Writing a test suite from scratch (use zuvo:write-tests), fixing systematic test
anti-patterns across many files (use zuvo:fix-tests), auditing test quality without execution (use
zuvo:test-audit), code quality review (use zuvo:review). Adding the single missing assertion that
a surviving mutant exposes is IN scope — that is the point of finding it.
Argument Parsing
Parse $ARGUMENTS as: [path | full | continue] [--max N] [--category CATEGORY] [--runner MODE] [--break N] [--no-install] [--dry-run] [--quick] [--report-only]
| Flag | Env equivalent | Effect |
|---|---|---|
[path] |
— | Scope to a specific directory or file |
continue |
— | Resume an interrupted run from its checkpoint (Phase 3.0). Re-runs nothing already resolved. |
full |
— | All production files that have test coverage |
--max N |
— | Max total LLM mutations to execute (default: 50). Does not bound the native runner, which mutates exhaustively by design. |
--category CATEGORY |
— | Only generate LLM mutations of this category: BOUNDARY, LOGIC, NULL, ERROR, STATE, ASYNC, SECURITY |
--runner MODE |
ZUVO_MUTATION_RUNNER |
auto (default) / native / llm / hybrid — see 0.1d |
--break N |
ZUVO_MUTATION_BREAK |
Fail the run when the final score_triaged is below N% (4.2c — evaluated after the 4.2b fix loop, not at 4.1). The flag overrides the env value; both are recorded with their source. |
--no-install |
ZUVO_MUTATION_NO_INSTALL=1 or ZUVO_NO_INSTALL=1 |
Never offer to install a mutation runner (disables the 0.1c consent gate). Detection still runs. |
--dry-run |
— | Generate mutations and show the plan, but do not execute any. Also suppresses 0.1c entirely. |
--quick |
— | Max 3 LLM mutations per file, max 20 total |
--report-only |
— | Report the score; do NOT fix surviving gaps (skips 4.2b). The only way to skip the fix loop. |
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.
- 2d ago First seen · 1,370 lines · 190 tokens per session scan A 27b47cdc8577
mutation-test is a skill published in the GitHub repository greglas75/zuvo (6 stars, last pushed 2d ago), licensed MIT. It adds 190 tokens to every session and 19,776 once invoked, about $0.0010 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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