first-contentful-paint

Use when auditing slow page loads, heavy assets, or rendering delays related to Optimize first contentful paint. Verify the actual bottleneck in DevTools, Lighthouse, or field data before recommending changes.

Quality

81%

Does it follow best practices?

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Adds up to 20 points to the overall score

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Securityby

Passed

No findings from the security scan

Quality

Content

70%

Reviews the quality of instructions and guidance provided to agents. Good implementation is clear, handles edge cases, and produces reliable results.

The body is a clean, well-organized overview with a properly signaled single-level reference to a real bundle file, but it spends tokens explaining FCP concepts Claude already knows and carries no executable code itself, leaving the actionability to the reference.

Suggestions

Drop or trim the opening "why FCP matters" sentence and the Explain section, since they restate concepts Claude already knows; keep only the actionable Quick Reference, Check, Fix, and Code Review guidance.

Add at least one minimal executable snippet inline (e.g., the Lighthouse/PerformanceObserver FCP measurement command) so the body is actionable without requiring a jump to the reference.

Tighten the description's trigger terms toward FCP-specific phrasing (e.g., "first contentful paint", "FCP score") to reduce overlap with sibling performance skills like LCP or TTFB.

Dimension	Reasoning	Score
Conciseness	The Quick Reference and Check/Fix/Code Review sections are lean, but the opening sentence ("FCP is the first visual signal... reducing perceived wait time and bounce rates") and the Explain section restate what FCP is and why it matters, which Claude already knows and the guidelines penalize.	2 / 3
Actionability	The body names concrete tools and techniques (Lighthouse, PageSpeed Insights, inline critical CSS, preconnect, defer JS) but provides no executable code in the body itself, deferring all code to references/rule.md; this is concrete guidance but incomplete on its own rather than copy-paste ready.	2 / 3
Workflow Clarity	For a simple single-purpose skill under 50 lines, the Check (measure, verify the 1.8s threshold) then Fix flow is clear and well-organized, and the Check section supplies an explicit verification checkpoint, satisfying the simple-skill allowance.	3 / 3
Progressive Disclosure	The body is a concise overview that clearly signals a single one-level-deep reference ("see `references/rule.md`") which is a real file, and rule.md is self-contained with no nested references, giving clear navigation and an appropriate content split.	3 / 3
	Total	10 / 12 Passed

Description

92%

Based on the skill's description, can an agent find and select it at the right time? Clear, specific descriptions lead to better discovery.

A well-constructed description with an explicit Use when trigger, natural keywords, and concrete named tools. Its main weakness is that the broad performance trigger terms create overlap risk with adjacent performance skills rather than scoping tightly to FCP.

Dimension	Reasoning	Score
Specificity	Names multiple concrete actions ("auditing slow page loads, heavy assets, or rendering delays", "Verify the actual bottleneck in DevTools, Lighthouse, or field data", "recommending changes") with specific named tools, matching the anchor for listing several specific concrete actions.	3 / 3
Completeness	An explicit "Use when auditing..." clause answers when, and the audit/verify/recommend framing answers what, satisfying the anchor requiring both what and when with explicit triggers; not capped at 2 because the Use when trigger is present.	3 / 3
Trigger Term Quality	Includes natural terms users would say ("slow page loads", "heavy assets", "rendering delays") alongside the recognized metric name and tool names (DevTools, Lighthouse), giving good coverage rather than jargon-only language.	3 / 3
Distinctiveness Conflict Risk	It is anchored to the distinct niche "first contentful paint", but the broad trigger terms ("slow page loads", "heavy assets", "rendering delays") overlap with sibling performance skills (LCP, TTFB, CLS), so it could still trigger for the wrong skill.	2 / 3
	Total	11 / 12 Passed

Validation

93%

Warnings & errors only

Checks the skill against the spec for correct structure and formatting. All validation checks must pass before discovery and implementation can be scored.

Validation — 15 / 16 Passed

Validation for skill structure

Criteria	Description	Result
metadata_version	'metadata.version' is missing	Warning

	Total	15 / 16 Passed

Repository: thedaviddias/Front-End-Checklist
Path: skills/first-contentful-paint/SKILL.md
Commit: 48405aa

Reviewed: about 12 hours ago

Table of Contents

Discovery Implementation Validation

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