The body is lean and assumes Claude's competence — it avoids explaining what doctest or docstrings are, and every code block and command earns its place; the directive table is the only borderline-verbose element but stays information-dense.

Fully executable, copy-paste-ready examples (sum, fibonacci, divide, directives) plus exact run commands, a complete pyproject.toml snippet, and a CI yaml block — concrete instruction rather than description.

Steps 1–8 are clearly sequenced, with 'Pass if the doctest output matches; fail if mismatch' providing an explicit verification checkpoint and Anti-patterns/Limitations acting as guardrails; no destructive or batch operations require additional feedback loops.

A self-contained SKILL.md with no bundle directories; sections are well-organized and the only references are one-level-deep external official docs, so navigation is clear without nested pointers.

Lists multiple concrete actions — 'Configures and runs', 'embeds executable test cases', 'supports ... directives', 'integrates with pytest via --doctest-modules', 'runs as python -m doctest module.py -v' — matching the 'lists multiple specific concrete actions' anchor.

Explicitly answers both what it does and when to use it via the 'Use for self-documenting reference implementations + simple smoke-test coverage embedded in API docs' clause, satisfying the explicit-trigger requirement.

Natural user-facing terms are well covered — 'doctest', 'docstrings', 'test cases', 'smoke-test', 'pytest', 'API docs' — the kinds of words a user would actually say when needing this skill.

Scoped tightly to Python stdlib doctest (plus pytest/Sphinx integration), a clear niche unlikely to trigger for the wrong skill; third-person voice is used throughout.