React and Next.js performance optimization guidelines from Vercel Engineering. This skill should be used when writing, reviewing, or refactoring React/Next.js code to ensure optimal performance patterns. Triggers on tasks involving React components, Next.js pages, data fetching, bundle optimization, or performance improvements.
The same skill appears in 2 more places: ClawHub, ClawHub
How to improve
For the model run — optional
Your own cases (evals/evals.json, 4–6 real requests with expected answers): the full check would then run those instead of a model-drafted suite.
A spec.yaml with trigger phrases and assertions — a behaviour contract for CI; `skilltest init` writes a template.
Guard findings · 0
✓ No critical or high findings
Files scanned: 69. Evidence is masked. Grey chips explain why severity was lowered.
Against the Agent Skills spec
✓ No remarks against the Agent Skills spec
Process rating: all ten parameters 55/100
0Result and completion. Does not say what the result is
0Inputs and preconditions. Does not say what the process needs to start
0Failures and branches. Linear process with no failure handling
0Progress reporting. Says nothing while it works
40Consistency. Frontmatter name (vercel-react-best-practices) differs from the folder (react-best-practices-2)
70When it triggers. States when to use, but not when not to
100Tools and files. No external tools needed
100Steps. 71 steps
100Execution cost. Instruction body is 1522 tokens
100Running it twice. No mutating operations
Everything here is measured from the skill text rather than judged by a model, so the numbers are checkable. A parameter weighs more when it is a more common reason for the process to stall.
Quality signals
+5Description has no quoted example phrases that should trigger the skill
+4Description does not say when NOT to use the skill (false activations)
+3Output format is not stated: the model decides each time
+2Single-language instructions
+3Description length 329: enough signal without eating the budget
+4Structure: 14 headings
+3Step-by-step instructions: 71 items
+4Has examples (1 code blocks)
+4Reference files are cited in the instructions (2 of 64)
+1License stated
Quality base 70; lint remarks subtract, signals add up to 100. Result: 89.
External checks
ClawHub: suspicious
This is a documentation-only React performance skill, but some examples promote risky handling of session cookies, inline scripts, and cross-request user-data caching without enough guardrails.
LLM: suspicious (high) · VirusTotal: · 29 May 2026