Conciseness

The 7-step 'How to use' summary is fully duplicated by the expanded 'Step 1-7' sections, and the Overview quotes five marketing-style feature bullets ('Interactive terminal based UI', 'Parallel and fast execution') that add no instructional value, with 'Per [mutmut-docs][md]' repeated ~10 times. The bulk (config table, commands, worked example) is efficient, so this sits between the 2 and 3 anchors — noticeably tighter than padding, but with several sections that could be trimmed.

Actionability

Concrete, copy-paste-style commands throughout (install, run, browse/apply/revert loop, CI yaml, worked example) cover the common cases. It falls short of 5 because the PR wrapper uses 'mutmut run --paths-to-mutate' and '--max-children 4' — 2.x-era flags inconsistent with the 3.x config style shown elsewhere ('pytest_add_cli_args_test_selection'), and the prose says to scope via source_paths while the script uses the flag.

Workflow Clarity

Steps 1-7 are clearly sequenced with explicit validation checkpoints: 'confirm the pytest / unittest suite is green before mutating', the apply → test-should-fail → git checkout revert loop, and the worked example's verify-and-rerun. The disk-writing mutant application is a risky batch-style operation and it has explicit feedback loops, so the workflow-clarity cap does not apply.

Progressive Disclosure

references/mutmut-pitfalls.md exists, is exactly one level deep, and is clearly signaled inline ('catalogued in [references/mutmut-pitfalls.md]'), verified against the actual bundle. It is not a 5 because offload is minimal — the mutator catalog and full CI yaml remain inline in a ~210-line body with only one reference file.

Specificity

The description enumerates multiple concrete actions — 'mutmut run, results and browse, applying survivors, pragma: no mutate suppressions and pyproject.toml config' — comprehensively covering the tool's workflow. It exceeds the 4 anchor because there are no meaningful gaps in capability coverage, and it is concrete rather than generic.

Completeness

Both parts are explicitly answered: 'Use when a Python pytest or unittest suite needs mutation testing...' gives a concrete when, and 'Sets up mutmut: mutmut run, results and browse, applying survivors...' gives a clear what. This matches the 5 anchor exactly rather than 4, since the 'when' clause is specific rather than vague.

Trigger Term Quality

Good natural keyword coverage: 'Python', 'pytest', 'unittest', 'mutation testing', 'tests catch bugs', and the tool name 'mutmut'. It falls short of the 5 anchor because common user variations like 'surviving mutants', 'test quality', or 'test suite strength' are absent.

Distinctiveness Conflict Risk

A clear niche — Python mutation testing with mutmut — with distinct triggers (pytest/unittest, mutation testing) that are unlikely to fire for unrelated skills. Minimal overlap risk with general testing or coverage skills.