Fetched per request
webstatus.dev
Baseline status, the browser versions a feature shipped in, Web Platform Tests scores and usage share. Cached at the edge for an hour, so the answer is never more than an hour behind the dashboard.
Model Context Protocol server
Know what CSS you
can actually ship.
Your agent guesses at browser support from whatever it read in training. This server gives it the real answer — live Baseline status from webstatus.dev, and MDN browser-compat-data for every property, selector and at-rule.
No key, no account, no rate limit. Read-only.
audit_css
Ready
Five tools, five questions
Each one answers something a developer actually asks mid-task. The agent picks by question, not by guessing at names.
-
“Which features exist for this, and are they safe yet?”
search_css_features
Search every CSS feature by keyword, Baseline status and the date it became interoperable.
Live · webstatus.dev
-
“What can I start using that I couldn't before?”
whats_new
Everything that reached Baseline in a date window, newest first, grouped by month.
Live · webstatus.dev
-
“Tell me everything about this one feature.”
get_feature
Baseline dates, shipping versions per browser, spec links, usage share, and the reference prose straight from MDN.
Live · webstatus.dev + mdn/content
-
“Which browser versions support this exactly?”
check_support
Per-browser versions for any property, value, selector, at-rule or function — including vendor prefixes and partial implementations.
Bundled · browser-compat-data
-
“Does this stylesheet work for my users?”
audit_css
Scans real CSS and reports every feature that misses your target, with the line it's on, what's wrong, and the minimum version that would work. Target a Baseline level or an explicit browser list.
Bundled · browser-compat-data
Connect it
Any MCP client that speaks Streamable HTTP. Pick yours.
Then ask: “audit src/styles.css for baseline-widely”.
Add to claude_desktop_config.json, then restart the app.
Cloudflare's AI Playground is a hosted MCP client. Paste the endpoint, connect, and the five tools appear.
Set transport to Streamable HTTP and connect to the endpoint above.
Where the answers come from
Two sources, split by how fast they change. Nothing is inferred, and nothing is remembered from training.
Compiled into the Worker
browser-compat-data
The CSS slice of MDN's compat dataset, plus the web-features catalog that
maps compat keys to Baseline features. Twenty megabytes upstream, compacted to
about 120 KB at build time — so support lookups and audits
answer with no network call at all.
Fetched per request
mdn/content
Reference prose, read from the Markdown source. The canonical slug is resolved through MDN first, because compat data records the URL a page had when the entry was written and MDN reorganises.