Chrome and Edge built a syllabus for your coding agent

What it does

Modern Web Guidance packages 103 web platform features—from container queries and the Popover API to scheduler.yield and cross-document view transitions—into a skill set consumed by coding agents. The guides are deliberately token-efficient and vetted through evals that prune content the models already know, aiming to close the gap between an LLM’s outdated training data and the current browser landscape. It is backed by the Google Chrome and Microsoft Edge teams.

The interesting bit

Instead of trusting an LLM to hallucinate the correct way to use anchor positioning or View Transitions, you feed it a curated guideline at query time. The project treats agent context windows as a scarce resource and optimizes for density, not comprehensiveness—favoring production-ready patterns over encyclopedic documentation.

Key highlights

• Covers 103 modern web features across CSS, HTML, DOM, performance, accessibility, and built-in AI.
• Guides are token-efficient and filtered by evals to avoid wasting context on patterns models already know.
• Supported by both the Google Chrome and Microsoft Edge teams.
• Includes responsible fallback strategies rather than defaulting to heavy polyfills or legacy libraries.
• Currently a preview release with active community contributions.

Caveats

• This is explicitly a preview release, so the content library and eval coverage are still expanding.

Verdict

Worth a look if you use coding agents and are tired of pull requests that polyfill native dialog behavior or reinvent scroll-driven animations with third-party libraries. If you do not use agent-assisted coding, the value proposition is largely moot despite the public guide files.