Dense PostHog-specific operational detail (TTL enum values, JOIN+variable materialisation trap, eligibility contract) with no generic concept padding Claude already knows; every section earns its place despite minor repetition in the closing notes.

Names exact tools, gives a copy-paste query_log SQL block, concrete decision-tree branches, and the literal API path to parse the endpoint name from — fully executable, not pseudocode.

A numbered workflow and ordered decision tree carry explicit validation checkpoints ("compare the results; only then apply", "confirm before applying it", "confirm first"), providing the validate→fix→retry loops the destructive query-rewrite step needs.

Sections are well organized with easy navigation, but the skill is a ~190-line monolith with all detail inline and no reference files; the under-50-line simple-skill exemption does not apply, so the split-into-references pattern of the top anchor is only partially met.

Lists four concrete named fixes — "bump the cache TTL, enable materialisation, restructure variables, or rewrite the query" — matching the anchor for multiple specific concrete actions rather than the partial-action level below.

Explicitly answers both what (diagnose and propose a concrete fix) and when ("Use when the user says…"), with an explicit trigger clause rather than leaving timing implied.

Quoted natural user phrases ("this endpoint is slow", "my endpoint times out", "we're hitting the cost cap on this one", "should I materialise this?") give good coverage of what a user would actually say, not just jargon.

Scoped to "a single named endpoint, not a project-wide audit" with PostHog-specific triggers, carving a clear niche unlikely to fire for unrelated skills.