Modern Web Guidance is a source repository for coding-agent skills that provide web-platform guidance, recommended practices, and browser compatibility information. It helps coding agents choose newer web APIs and patterns when generating web applications. The catalogue skills are the guidance produced and maintained by this project.
Borrowing it
Nothing to install: this file belongs to GoogleChrome/modern-web-guidance-src. Take a copy, put it at the same path in your own repository, and replace the rules that are about this project with yours.
curl -O https://raw.githubusercontent.com/GoogleChrome/modern-web-guidance-src/main/.agents/skills/web-baseline/SKILL.mdgit clone --depth 1 https://github.com/GoogleChrome/modern-web-guidance-srcWrote this? Show the measurements
A badge with what this costs and how it scanned, read live from this page, so it follows the numbers instead of freezing them. Markdown for a README, HTML for a documentation site or a project page.
[](https://agentmods.dev/skills/googlechrome/modern-web-guidance-src/web-baseline)<a href="https://agentmods.dev/skills/googlechrome/modern-web-guidance-src/web-baseline"><img src="https://agentmods.dev/badge/skills/googlechrome/modern-web-guidance-src/web-baseline/github.svg" alt="Measured on agentmods" height="20"></a>Or the 80×15 button, for a site that already has a row of RSS and ATOM ones. Only the verdict fits; the numbers stay here.
<a href="https://agentmods.dev/skills/googlechrome/modern-web-guidance-src/web-baseline"><img src="https://agentmods.dev/badge/skills/googlechrome/modern-web-guidance-src/web-baseline.svg" alt="Reviewed on agentmods" width="80" height="20"></a>- NVIDIA SkillSpector pass
What it costs to keep this loaded
Counted locally with the o200k_base tokenizer, which is exact for GPT models; Claude uses its own tokenizer and its counts differ. Treat this as one consistent yardstick across the catalogue rather than a bill. Prices are per million input tokens.
| Model | Per session | Once invoked |
|---|---|---|
| Fable 5.1 | $0.00019 | $0.00209 |
| Opus 5.5 | $0.00008 | $0.00084 |
| Sonnet 5.5 | $0.00004 | $0.00042 |
| Haiku 4.5 | $0.00002 | $0.00021 |
Grade A, and why
baseline-status scanned grade A with 0 findings against 26 rules in 11 categories — prompt injection, anti-refusal, data exfiltration, privilege escalation, supply chain, agent snooping, system-prompt leakage, SSRF and excessive agency — measured 1mo ago.
A static scan of the body, not an audit. Every finding is printed with the line that produced it so you can judge whether it matters here. A mod is markdown that instructs an agent; that is exactly why what it instructs is worth reading.
Nothing flagged
None of the 26 patterns this scan looks for appear in this file: no shell pipes, no recursive deletes, no credential paths, no hidden text, no instruction-override or anti-refusal phrasing, no agent-config snooping. That is not a guarantee, it is the absence of the things that are checkable.
What it actually says
Web Baseline Status Skill
Use this skill when you need to verify if a web feature is ready for use or when you need browser support data for specific features.
Tool Usage
Basic Search: To search for features by ID or description:
pnpm baselinestatus <query>
Example: pnpm baselinestatus over
JSON Output: To get structured output for easier parsing:
pnpm baselinestatus <query> --json
Example: pnpm baselinestatus over --json
Baseline Status Mapping
The output maps internal status codes to human-readable terms:
- Widely (
high): Supported by all major browsers for a significant time. - Newly (
low): Recently supported by all major browsers. - Limited (
false): Not yet supported by all major browsers.
What this file has done since we first saw it
Hashed on every crawl. A supply-chain change to an agent config is a question of when, not whether, so the history is kept rather than the latest state alone.
- 1mo ago First seen · 34 lines · 19 tokens per session scan A 971ded5d51e5
baseline-status is a skill published in the GitHub repository GoogleChrome/modern-web-guidance-src (1,202 stars, last pushed today), licensed Apache-2.0. It adds 19 tokens to every session and 209 once invoked, about $0.0001 per session on Opus 5.5. A static security scan graded it A with 0 findings. No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-30.
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