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/project-maintenance/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/project-maintenance)<a href="https://agentmods.dev/skills/googlechrome/modern-web-guidance-src/project-maintenance"><img src="https://agentmods.dev/badge/skills/googlechrome/modern-web-guidance-src/project-maintenance/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/project-maintenance"><img src="https://agentmods.dev/badge/skills/googlechrome/modern-web-guidance-src/project-maintenance.svg" alt="Reviewed on agentmods" width="80" height="20"></a>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 | $0.00025 | $0.00329 |
| Opus 5.5 | $0.00010 | $0.00132 |
| Sonnet 5.5 | $0.00005 | $0.00066 |
| Haiku 4.5 | $0.00003 | $0.00033 |
Grade A, and why
project-maintenance 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 18d 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
Repository Maintenance
Things that should happen with some regularity across the repository:
Vendored Dependencies
Check if upstream packages have newer releases than what we vendored:
echo "Upstream: $(npm info @vercel/detect-agent version)" && echo "Vendored: $(grep -o 'detect-agent@[0-9.]*' src/cli/telemetry/detect-agent.ts)"
If updated, sync changes to src/cli/telemetry/detect-agent.ts, bump the version comment, and run node --test src/cli/telemetry/detect-agent.test.ts src/cli/telemetry/clearcut-logger.test.ts.
Web Standards & Compatibility Datasets
web-features: Automated via.github/workflows/update-web-features.yml(Mon/Thu). Can also be run manually withpnpm update web-features, followed bysrc/ci/generate-feature-to-groups.tsandsrc/ci/validate-after-web-feature-update.ts.- Compat & WebRef: Periodically bump
@mdn/browser-compat-data,@webref/css,@webref/elements,@webref/idl,caniuse-lite, andmdn-data.
Document Coherence & Link Integrity
node .agents/skills/coherence-auditor/scripts/coherence-audit.ts
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.
- 18d ago Changed c93c3f19abc9
- 24d ago First seen · 25 lines · 25 tokens per session scan A 49b11da05ddd
project-maintenance 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 25 tokens to every session and 329 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 2026-10-03.
Other skills, from other repositories
story-readiness
Checks whether a story is ready to implement: clear acceptance criteria, no open questions, valid ADR and dependencies. Use when the user asks if a story, or the sprint's stories, are ready to start or build.
recipe-create-meet-space
Create a Google Meet meeting space and share the join link.
workthreads
SpecStory Workthreads - a weekly work-thread rollup across a team's repos from SpecStory coding histories (any agent - Claude Code, Codex, Cursor, Gemini, and more). It groups the window's sessions into threads of work per project and labels each new / open / recently closed, so a lead sees what shipped, what is still…
atmos-config
Atmos root configuration: atmos.yaml discovery, precedence, deep merging, basepath, imports, minimal bootstrap, and routing to narrower Atmos skills.
qa-project-bootstrap
Onboard a new QA engineer to an existing codebase, or audit an existing test architecture. Produces a 30-day ramp plan: codebase orientation, framework walkthrough, test architecture audit, mentorship pairing, and first-test guidance. Use when: "QA onboarding," "new tester," "ramp up," "test architecture audit,"…
remove
Remove a deployed framework or addon from the current workspace.