The body is lean and assumes Claude's competence — no explanation of what ScienceWorld is or why ambiguity occurs — with every example earning its place; it avoids the padded concept-explanation pattern of levels 1-2.

It gives the exact recognition phrase, the concrete rule ('Choose 0 (the first option)'), and copy-ready example actions ('> 0'), fully executable guidance rather than the vague or pseudocode patterns of lower anchors.

Per the simple-skill guideline, this single-action mechanic is unambiguously sequenced (Recognize → Scan → Select → Execute) with anti-patterns scoping misuse; no destructive/batch validation is needed, so the top anchor applies.

At under 50 lines with well-organized sections (Purpose, When to Use, Workflow, Examples, Anti-Patterns), it meets the guideline for scoring 3 on small self-contained skills without requiring external file references.

The description names concrete actions — returning 'an "Ambiguous request" prompt', 'selecting the lowest available number (typically 0)' — matching the anchor for multiple specific concrete actions rather than a vague domain reference (level 2).

It opens with an explicit 'Use when' clause and states what the skill does ('resolves the disambiguation by selecting the lowest available number'), clearly answering both what and when per the top anchor.

It uses natural terms a user would say — 'Ambiguous request prompt', 'identical action options', 'ScienceWorld environment' — giving good coverage rather than only jargon (level 1) or partial keywords (level 2).

The niche is narrow and tied to ScienceWorld's exact ambiguity prompt, so it is unlikely to trigger for unrelated skills, matching the 'clear niche with distinct triggers' anchor.