ttfb

Use when auditing slow first responses on SSR pages, APIs, or cacheable HTML. Distinguish origin compute time from network latency and CDN cache misses before proposing a fix.

Quality

70%

Does it follow best practices?

Run evals on this skill

Adds up to 20 points to the overall score

View guide

Securityby

Passed

No findings from the security scan

Fix and improve this skill with Tessl

tessl review fix ./skills/ttfb/SKILL.md

Quality

Content

53%Weight 40%Scale 1-5

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 reasonable overview that defers detail to a real, well-structured references/rule.md file. It is held back by mild over-explanation of well-known concepts, no inline executable code, and validation steps that are only present in the referenced file rather than the main workflow.

Suggestions

Trim the opening sentence and merge the redundant Check/Fix/Explain sections into the concrete Code Review guidance to reduce token overhead on concepts Claude already knows.

Inline one or two copy-paste-ready checks (e.g. a DevTools/curl command to read TTFB, or the Cache-Control header snippet from rule.md) so the body is actionable without opening the reference.

Add an explicit inline validation checkpoint in the workflow (e.g. 'Confirm TTFB < 800ms for key routes after changes') rather than only describing verification in references/rule.md.

Dimension	Reasoning	Score
Conciseness	The body is mostly compact, but the opening line ("TTFB is the foundation of page performance; if the server is slow to respond, all subsequent loading stages are delayed") and the terse Check/Fix/Explain sections restate concepts Claude already knows and could be tightened.	3 / 5
Actionability	The Code Review section gives concrete flags (uncached HTML, synchronous work before the first byte, repeated upstream fetches, the ~800ms threshold) but the main body contains no executable code or commands; concrete examples are deferred entirely to references/rule.md.	3 / 5
Workflow Clarity	A rough Check -> Fix -> Explain -> Code Review sequence is present, but validation checkpoints live in references/rule.md rather than the body, so the main workflow lacks explicit verify/re-test steps inline.	3 / 5
Progressive Disclosure	Clear sectioned overview with a single well-signaled one-level-deep reference ("see references/rule.md") that exists in the bundle, though the inlined Quick Reference/Check/Fix/Explain sections slightly duplicate content that could live in the reference.	4 / 5
	Total	13 / 20 Passed

Description

87%Weight 40%Scale 1-5

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 strong, well-scoped description that clearly states both trigger conditions and the diagnostic framing it applies. It is concise and third-person with minimal fluff; the main improvement would be adding the common synonyms "TTFB" / "server response time" to broaden natural trigger coverage.

Dimension	Reasoning	Score
Specificity	Names the domain and several concrete actions (auditing first responses, distinguishing origin compute from network latency and CDN cache misses, proposing a fix), but the actions are framed somewhat abstractly rather than as discrete discrete verbs, leaving minor gaps versus the comprehensive anchor.	4 / 5
Completeness	Explicitly answers both what ("Distinguish origin compute time from network latency and CDN cache misses before proposing a fix") and when ("Use when auditing slow first responses on SSR pages, APIs, or cacheable HTML") with concrete trigger phrases.	5 / 5
Trigger Term Quality	Good coverage of natural phrases users would say ("slow first responses", "SSR pages", "APIs", "cacheable HTML", "CDN cache misses"), but misses common synonyms like "TTFB", "server response time", or "Time to First Byte" that a user would naturally invoke.	4 / 5
Distinctiveness Conflict Risk	Carves a clear niche (first-byte latency diagnosis distinguishing origin vs network vs CDN) that is unlikely to trigger for unrelated performance skills, with minimal overlap risk.	5 / 5
	Total	18 / 20 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/ttfb/SKILL.md
Commit: 30756a7

Reviewed: 20 days ago

Table of Contents

Discovery Implementation Validation

Is this your skill?

If you maintain this skill, you can claim it as your own. Once claimed, you can manage eval scenarios, bundle related skills, attach documentation or rules, and ensure cross-agent compatibility.