ha-mcp-worker

Cloudflare Worker that serves inline JS/CSS as hosted resources for Home Assistant AI integrations.

Why?

Browser CORS restrictions prevent data: URIs from working with ES6 modules. This worker provides a workaround by converting base64-encoded code to proper HTTPS URLs.

Usage

https://ha-mcp-resources.rapid-math-bbad.workers.dev/{base64_content}?type=module|js|css

Example

// Original code
const code = `export default class MyCard extends HTMLElement { }`;

// Encode to URL-safe base64
const encoded = btoa(code).replace(/\+/g, '-').replace(/\//g, '_');

// Use as module URL
const url = `https://ha-mcp-resources.rapid-math-bbad.workers.dev/${encoded}?type=module`;

Resource Types

Type	Content-Type	Use Case
module	application/javascript	ES6 modules (default)
js	application/javascript	Plain JavaScript
css	text/css	Stylesheets

Constraints

• Max size: ~24KB of source code (32KB base64-encoded URL path limit)
• Immutable: Content is cached for 1 year (URL = content)
• Public: No authentication, content is accessible to anyone with the URL

Privacy

• No logging: Worker logs and observability are disabled
• No storage: Content is never stored - decoded on-the-fly from URL
• No analytics: No tracking or telemetry

Local Development

# Install dependencies
pnpm install

# Run locally (http://localhost:8787)
pnpm dev

# Run tests
pnpm test

# Type check
pnpm typecheck

# Deploy
pnpm publish:worker

Deployment

Automatic deployment on push to main via GitHub Actions.

Required Secrets

Secret	Description
CLOUDFLARE_API_TOKEN	API token with Workers edit permission
CLOUDFLARE_ACCOUNT_ID	Your Cloudflare account ID

Related

• ha-mcp - Home Assistant MCP server
• Issue #266 - Feature request