Conciseness

The Rules section systematically restates the Workflow steps ('Cost = data-read-per-call × call-volume' repeats step 3; the confirm-cost rule repeats step 6), and the intro carries unnecessary flourish ('Supabase's structural consent for paid actions'). Content is domain-specific and mostly efficient, but the redundancy is systematic rather than minor, matching anchor 3 rather than 4.

Actionability

Concrete guidance throughout: named MCP tools ('insights', 'tables', 'functionSpec'), the ranking formula ('bytes/documents read per call × observed (or asked-about) call volume'), and specific fixes ('.paginate/.take instead of .collect', 'an aggregate component for counts'). Not 5 because no example MCP call, finding payload, or report format is shown — 'emit it as a cost-class finding on the bus' leaves the output shape unspecified.

Workflow Clarity

Seven clearly sequenced steps with explicit gates (GUARD deploy-guard, CONFIRM-COST 'get an explicit yes BEFORE proceeding') and a conditional branch for zero traffic. Not 5: there is no verification step reconciling the ranking against total insights and no error-recovery path if MCP tools are unavailable — minor validation gaps place it at anchor 4.

Progressive Disclosure

A self-contained ~24-line body with clean Workflow/Rules sections, no inlined reference dumps, and no nested references. The skill is under 50 lines with no need for external bundle files (none exist), so per the rubric's simple-skill guidance the well-organized sections earn a 5.

Specificity

Lists four mechanism-level concrete actions — 'rank functions by bytes/documents-read × call-volume from insights', 'project each cost driver's growth curve', 'name the cheapest fix', 'confirm-cost for paid actions' — naming the specific data signals involved. Matches the comprehensive-coverage anchor better than 4, since no concrete capability of the skill is omitted.

Completeness

The 'what' is clear and multi-part, but there is no 'Use when...' clause or equivalent explicit trigger guidance — per the judging guidelines this caps completeness at 3. The 'when' is only weakly implied by 'confirm-cost for paid actions'.

Trigger Term Quality

Natural terms include 'Convex spend', 'cost driver', 'growth curve', and 'paid actions', which a cost-conscious user would plausibly say. Misses common variations such as 'bill', 'pricing', or 'how much will this cost', so it sits above anchor 3's sparse keyword set but below anchor 5's comprehensive synonym coverage.

Distinctiveness Conflict Risk

'Preview Convex spend' carves a clear cost-analysis niche with minimal conflict against non-Convex skills. However, the evidence terms ('bytes/documents-read', 'call-volume', 'insights') overlap with a same-platform perf/advisor skill, giving minor overlap risk with closely related skills — anchor 4 rather than 5.