Flutter Motion Kit

A collection of previewable Flutter animations, each annotated with its pitfalls (with sources and confidence), and reusable from Claude Code / Cursor in one click (MCP).

🎛 Live interactive playground: motion.markxian.cn · 📚 Verified catalog: motion.markxian.cn/gallery

Claude Code — one line:

claude mcp add --transport http flutter-motion https://mcp.markxian.cn/mcp

One-click connect (remote MCP · zero install)

Hosted on a Cloudflare Worker — add one URL and go, content updates take effect instantly:

Claude Code

claude mcp add --transport http flutter-motion https://mcp.markxian.cn/mcp

Cursor / VS Code — import with one button:

Prefer offline/local (npx, no hosting)? See Connect Claude Code (local) below.

One structured source, three outputs:

content/animations/<id>/{meta.yaml, main.dart, bad.dart}   ← single source of truth
        │  scripts/build-catalog.mjs (schema validation + aggregation)
        ▼
   catalog.json
   ├──▶ Site (Astro): real running Flutter web previews (self-hosted) + code + pitfalls + [Copy for AI]
   └──▶ MCP server: search / get / list_pitfalls, callable directly by AI coding assistants

Why this isn't just another snippet blog

"Best practices" shouldn't rest on someone's word — they should be provable + sourced + machine-verified:

• Every pitfall carries a source + confidence (official-docs / measured / author-experience …) — an honest signal of how strong the basis is, returned to the AI alongside the code.
• CI gate: every main.dart must pass dart format + flutter analyze (very_good_analysis) + flutter build web; if it doesn't, it isn't included.
• Reproducible: every entry self-hosts a real running Flutter web preview (compiled by npm run previews, not a screen recording); bad.dart demonstrates the wrong way for side-by-side comparison.
• Anti-rot: every entry records verifiedOn, and CI re-runs monthly to catch deprecations in new Flutter releases.

Quick start

npm install

# 1) Build the catalog (validate schema → catalog.json)
npm run catalog

# 2) Build the self-hosted previews (compile each main.dart into runnable Flutter web)
#    Requires a local Flutter (auto-detects fvm; outputs to site/public/preview/, gitignored)
npm run previews

# 3) Run the site locally (embeds the running previews + copy buttons)
npm run site:dev

# 4) Build and connect the MCP server
npm run mcp:build

Connect Claude Code (one-click reuse)

Once published to npm, anyone can connect with zero install:

claude mcp add flutter-motion -- npx -y flutter-motion-mcp

Local dev build:

npm run mcp:build
claude mcp add flutter-motion -- node /abs/path/to/flutter-motion-kit/mcp/dist/index.js

Then, right in Claude Code: "find a Flutter list-entrance animation and add it to my page" — it calls search_flutter_animation → get_animation and lands the verified code + pitfalls.

MCP tools

Tool	Purpose
search_flutter_animation	Search animations by keyword/category (returns summaries)
get_animation	Return full code + pitfalls + sources by id
list_pitfalls	Pull the pitfall list for an AI to self-check after writing
list_categories	Browse categories

Deploy the remote MCP (Cloudflare Worker)

cd worker
npm i -g wrangler && wrangler login

cp wrangler.toml.example wrangler.toml   # real config stays out of the repo (gitignored)

# Create the KV namespace (connection counter) and put the printed id into your local wrangler.toml
wrangler kv namespace create STATS
wrangler kv namespace create STATS --preview

npm run deploy        # rebuilds the catalog and bundles + deploys

After deploy: /stats shows the live connection count, /mcp is the MCP endpoint, / shows connect hints.

On the site side: cp site/.env.example site/.env and set PUBLIC_MCP_ORIGIN to your Worker endpoint (this .env is also kept out of the repo).

Private deploy config: worker/wrangler.toml, site/.env, and .dev.vars are all gitignored — your KV id / account / subdomain never appear in the public repo, which only keeps *.example placeholders. To avoid exposing even the account subdomain, bind a custom domain to the Worker (see the comments in wrangler.toml.example).

Stats: each initialize counts one connection (an approximate KV counter — good enough for a live badge). For exact de-duplication, upgrade to a Durable Object / Analytics Engine.

Layout

content/animations/   # single source of truth (one directory per animation)
schema/               # JSON Schema for meta.yaml
scripts/              # build-catalog (aggregate) / build-previews (self-hosted previews) / sync-gists (DartPad, optional)
site/                 # interactive playground at / + verified gallery at /gallery (Astro)
mcp/                  # MCP server (TypeScript)
.github/workflows/    # verify: schema + analyze + format + build

Contributing

Please run through the quality checklist in CONTRIBUTING.md before adding a new animation. Corrections via issue/PR are welcome — being publicly correctable is exactly what makes this more trustworthy than a blog.

License

MIT