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Web Vitals & Chrome DevTools Profiler

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Created by WebPerf Lab•fullstack Workflow

10,500

Optimize Largest Contentful Paint (LCP), Cumulative Layout Shift (CLS), and Interaction to Next Paint (INP).

Supported Runtimes:codexclaude-codecursorwindsurf
Universal 1-Click Installer
npx askills install performance-profiler
Installs automatically to ~/.agents/skills or ~/.codex/skills
•Raw Endpoint

Overview & Problem Solved

When modern frontier LLMs (like Claude 3.7, GPT-4o, or deep reasoning agents) execute complex domain tasks without standard operating procedures, they frequently suffer from context drift, incorrect CLI arguments, or non-standard file hierarchies. Web Vitals & Chrome DevTools Profiler eliminates probabilistic guessing by supplying the Agent with an authoritative, sandboxed execution specification.

By packaging verified workflows into a structured SKILL.md manifest, this skill establishes deterministic boundaries, verifies dependencies, and executes tasks using proven engineering conventions.

Core Capabilities & Guarantees

Deterministic SOP Enforcement

Follows pre-tested instructions and step-by-step algorithms, avoiding experimental or hallucinated flags.

Multi-Runtime Isolation

Runs with identical behavioral fidelity across OpenAI Codex, Claude Code, Cursor IDE, and Windsurf Cascade.

Sandbox-Scoped Boundaries

Enforces workspace-scoped file mutations and shields environment secrets against accidental prompt leakage.

Self-Healing QA Verification

Automates test verification, linter checks, and syntax validation before completing any user turn.

Agent Execution Pipeline

1

Intent Matching & Context Ingestion

The agent scans the user request against the skill's YAML frontmatter triggers and loads the verified instructions into active working memory.

2

Toolchain & Dependency Validation

The runtime verifies that necessary tools, interpreters, and environment configurations exist within the workspace sandbox before proceeding.

3

Deterministic Execution & Delivery

The agent executes the codified SOP, runs verification checks, and outputs high-fidelity deliverables without extraneous narration.

Validated Prompt Templates

(Click to copy)

“Analyze our Next.js bundle trace and eliminate duplicate dependencies from First Load JS.”

“Fix layout shifts caused by web fonts by configuring font-display: swap and size-adjust.”

“Optimize image loading by converting hero images to WebP/AVIF with priority preloading.”

Automated Security & Audit Report

Score:98/100 (SAFE)
Filesystem

Workspace Scoped

Cannot escape workspace root
Shell Execution

Instruction Only

Zero system subprocesses
Network Access

Offline Sandbox

No internet egress
API Keys Required

None Required

Runs fully standalone
Audited and verified safe for local agent execution.

Enterprise & Production Use Cases

Autonomous Development SprintsEnables coding agents to independently build features, run lint tests, and author PR descriptions that strictly conform to organizational coding rules.
Batch Automation & CI/CD PipelinesAutomates repetitive transformations such as document generation, schema migrations, or test-suite updates inside containerized CI runners.
Standardized Engineering OnboardingDistributes unified development playbooks across all engineering team members using Cursor, Codex, or Claude Code.

Frequently Asked Questions

Q: What makes Web Vitals & Chrome DevTools Profiler different from a standard MCP server?

MCP (Model Context Protocol) provides external protocol connections to databases or APIs. In contrast, Web Vitals & Chrome DevTools Profiler is a high-level operational skill (SKILL.md) that teaches AI Agents procedural intelligence, deterministic step-by-step SOPs, parameter constraints, and self-correction workflows.

Q: Is Web Vitals & Chrome DevTools Profiler compatible with frontier models like Claude 3.7 Sonnet, GPT-4o, and DeepSeek-R1?

Yes. The skill is packaged with standard markdown instructions (SKILL.md) and YAML frontmatter, adhering to the universal agent skill standard natively supported across Codex, Claude Code, Cursor, and Windsurf.

Q: What permissions does Web Vitals & Chrome DevTools Profiler require in agent mode?

Every listed skill undergoes automated static analysis scoring 98/100. It strictly adheres to workspace-scoped filesystem boundaries and does not execute untrusted remote code.

Q: Can our team customize or extend the rules in this SKILL.md?

Yes. Once installed in your project root (.skills/performance-profiler/SKILL.md or ~/.agents/skills/performance-profiler/), you can customize the instructions to include internal team guidelines, custom linters, or proprietary APIs.

SKILL.md Source Specification

View Raw
---
name: "performance-profiler"
description: "Optimize Largest Contentful Paint (LCP), Cumulative Layout Shift (CLS), and Interaction to Next Paint (INP)."
---

# Web Vitals & Chrome DevTools Profiler

Diagnoses long JavaScript tasks, unoptimized web fonts, excessive DOM node counts, and React re-renders.

## Instructions and Rules
1. Read existing repository patterns before making modifications.
2. Adhere strictly to the workspace directory boundaries.
3. Verify changes with unit or integration tests before concluding.