css-noop-checker
Chrome DevTools extension (and MCP tool server) that detects CSS declarations that have no visible effect on the selected DOM element or across the full page. It uses computed styles plus heuristics, and reports actionable warnings with fix suggestions. The MCP server exposes the rules engine for AI-assisted analysis using Playwright.
Score Breakdown
⚙ Agent Friendliness
🔒 Security
No hosting/security posture is described (appears local/devtools/MCP with Playwright). Primary risks are typical for tooling that runs a headful/headless browser against provided pages: untrusted page content could affect the browsing session; secrets are not discussed, but there is no indication that secrets are used. TLS/rate-limits/scoping not applicable from provided docs.
⚡ Reliability
Best When
You are developing web UI in Chromium-based browsers and want fast feedback on CSS declarations that are silently ignored due to layout context, optionally via an MCP-enabled agent workflow.
Avoid When
You need deterministic, spec-perfect linting independent of the browser engine; or you cannot run Playwright/Chromium to evaluate computed styles.
Use Cases
- • Linting/debugging CSS by identifying no-op properties for a specific element in Chrome DevTools
- • Automated auditing of pages (selected element or full-page scan) to find ineffective CSS
- • AI-assisted layout/CSS reviews by calling MCP tools to run the same detection rules programmatically
- • Regression checks for style changes by re-running computed-style-based heuristics in end-to-end tests
Not For
- • Server-side CSS linting unrelated to browser layout behavior
- • Cases where DOM structure/layout context is not available (since effectiveness depends on context)
- • Strict standards-only interpretation of CSS (project emphasizes Chromium behavior and browser coverage)
- • Production runtime monitoring in end-user environments (it is a DevTools extension / analysis tool)
Interface
Authentication
No authentication model is described; MCP/extension usage appears local/devtools-oriented rather than a hosted service.
Pricing
No pricing information provided; appears to be free/open-source tooling.
Agent Metadata
Known Gotchas
- ⚠ Results depend on Chromium behavior and page layout context; the same CSS may produce different warnings across browsers or dynamic DOM states.
- ⚠ Full-page scans can be more expensive than selected-element mode; agents should manage workload/timeouts when calling the MCP tools.
- ⚠ Rule correctness relies on computed styles/heuristics and Playwright coverage; treat detections as guidance rather than formal proof.
Alternatives
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Scores are editorial opinions as of 2026-03-30.