MotionSpec — web animation accessibility MCP Server

Static motion-a11y checker: fetches a URL's HTML + linked stylesheets (up to 12 sheets, 2 MB per response, 8 s timeout) and scans the CSS for (1) animation/transition that moves without an effective (cascade-aware) prefers-reduced-motion guard, (2) animated non-transform/opacity properties, (3) infinite animations with no pause path, (4) <marquee>/autoplay >5s. Colour/opacity-only transitions are not motion (WCAG 2.3.3). Uses scoring v2. Same engine and scoring as the free site check at https://motionspec.dev/motion-check. Returns structuredContent {ok, url, status, score, scoring, scoring_doc, findings, groups, summary, badge, disclosures, coverage} plus a Markdown report in text content, or {ok:false, error} with isError:true on failure. Read status first: pages without CSS motion return status 'not-measurable' with score null; runtime motion such as WAAPI/GSAP/WebGL is not audited. Loading indicators are reported as 'review', not as violations; verify them manually. The 'reduced-motion-safe' badge requires a measurable page with zero findings and no detected runtime motion library. Does network I/O (openWorldHint).

Returns the catalog of verified motion primitives (names, purpose, parameter schemas, defaults) plus the authoring rules for writing a MotionSpec. Call this FIRST, then write the spec yourself, check it with motion_validate and compile it with motion_compile. Free motion check: https://motionspec.dev/motion-check · paid Motion Report (9 USD, one-time): https://motionspec.dev/pricing?src=mcp-motion_catalog#p-report.

Validates (fail-closed) and deterministically compiles a MotionSpec into vanilla-GSAP JavaScript and CSS, with prefers-reduced-motion enabled by default and a performance-budget report. Same spec always yields identical code. Returns {ok:true, js, css, warnings, report, catalogVersion} or {ok:false, errors, catalogVersion}; css may be null when no CSS is emitted. Read warnings before shipping: explicitly disabling reduced-motion or loop pause controls can compile with accessibility warnings. Does not write files or execute the emitted code.

Operator telemetry of the hosted service (not your own usage); needs the operator key (header x-motionspec-key). This unauthenticated call returns access information only; it does not compile code, fetch URLs, run an audit or read usage data. Arguments are optional and unused. Returns isError:true with structuredContent {ok:false, error:'KEY_REQUIRED', tool, freeLocalAlternative} and text guidance. For your own local activity use 'npx -p motionspec motion stats' (MIT). It reads this machine's local activity, not hosted usage.

Checks a MotionSpec against the schema, the primitive allow-list, parameter bounds and injection rules. Fail-closed: returns ok=false with precise errors. Returns {ok, errors, warnings, deprecations, catalogVersion}. IMPORTANT: warnings[] carries the WCAG 2.2.2 / reduced-motion findings and can be non-empty while ok=true — a spec that compiles is not automatically accessible. Use to pre-check a spec before compiling.