@25xcodes/llmfeed-signer

Ed25519 key generation and LLMFeed signing tool for the WebMCP ecosystem.

Installation

npm install @25xcodes/llmfeed-signer

Or use directly with npx:

npx @25xcodes/llmfeed-signer keygen

CLI Usage

Generate Keypair

Generate a new Ed25519 keypair for feed signing:

# Generate keys in ./keys directory
llmfeed-sign keygen

# Custom output directory and name
llmfeed-sign keygen --output ./my-keys --name mysite

This creates:

• mysite.private.pem - Private key (keep secret!)
• mysite.public.pem - Public key (publish to your server)
• mysite.private.base64 - Base64 key for environment variables

Sign a Feed

Sign an LLMFeed JSON file:

# Basic signing
llmfeed-sign sign mcp.llmfeed.json --key ./keys/mysite.private.pem

# With public key URL (recommended)
llmfeed-sign sign mcp.llmfeed.json \
  --key ./keys/mysite.private.pem \
  --public-url https://example.com/.well-known/public.pem

# Sign specific blocks only
llmfeed-sign sign feed.json \
  --key private.pem \
  --blocks metadata,capabilities,agent_guidance

# Modify in place
llmfeed-sign sign feed.json --key private.pem --in-place

Verify a Signature

Verify a signed feed:

# With local public key
llmfeed-sign verify signed.json --key ./keys/mysite.public.pem

# Auto-fetch from public_key_hint in feed
llmfeed-sign verify signed.json

# JSON output for scripting
llmfeed-sign verify signed.json --json

Library Usage

import {
  generateKeyPair,
  signFeed,
  verifyFeed,
} from '@25xcodes/llmfeed-signer'

// Generate keypair
const keyPair = await generateKeyPair()
console.log(keyPair.publicKeyPem)  // PEM for publishing
console.log(keyPair.privateKey)    // Base64 for env vars

// Sign a feed
const feed = {
  feed_type: 'mcp',
  metadata: {
    title: 'My API',
    origin: 'https://example.com',
    description: 'My awesome API'
  },
  capabilities: [/* ... */]
}

const signed = await signFeed(feed, keyPair.privateKey, {
  publicKeyUrl: 'https://example.com/.well-known/public.pem',
  signedBlocks: ['metadata', 'capabilities'],
  trustLevel: 'self-signed'
})

console.log(signed.feed)           // Feed with trust & signature blocks
console.log(signed.signature)      // Base64 Ed25519 signature
console.log(signed.payloadHash)    // SHA-256 of canonical payload

// Verify a feed
const result = await verifyFeed(signed.feed, keyPair.publicKey)
console.log(result.valid)          // true
console.log(result.signedBlocks)   // ['metadata', 'capabilities']

CI/CD Integration

GitHub Actions

name: Sign LLMFeed

on:
  push:
    paths:
      - 'mcp.llmfeed.json'

jobs:
  sign:
    runs-on: ubuntu-latest
    steps:
      - uses: actions/checkout@v4
      
      - name: Setup Node.js
        uses: actions/setup-node@v4
        with:
          node-version: '20'
      
      - name: Sign feed
        env:
          MCP_PRIVATE_KEY: ${{ secrets.MCP_PRIVATE_KEY }}
        run: |
          npx @25xcodes/llmfeed-signer sign mcp.llmfeed.json \
            --key <(echo "$MCP_PRIVATE_KEY") \
            --public-url https://example.com/.well-known/public.pem \
            --in-place
      
      - name: Commit signed feed
        run: |
          git config user.name "github-actions[bot]"
          git config user.email "github-actions[bot]@users.noreply.github.com"
          git add mcp.llmfeed.json
          git commit -m "chore: re-sign LLMFeed" || exit 0
          git push

Cloudflare Workers

// Sign at request time
import { signFeed } from '@25xcodes/llmfeed-signer'

export default {
  async fetch(request: Request, env: Env) {
    const manifest = buildManifest()
    
    const signed = await signFeed(manifest, env.MCP_PRIVATE_KEY, {
      publicKeyUrl: 'https://example.com/.well-known/public.pem'
    })
    
    return new Response(JSON.stringify(signed.feed, null, 2), {
      headers: { 'Content-Type': 'application/json' }
    })
  }
}

Security Notes

1. Never commit private keys - Use environment variables or secrets management
2. Rotate keys periodically - Generate new keypairs and update signatures
3. Verify before trusting - Always verify signatures before consuming feed data
4. Use HTTPS - Host public keys only over HTTPS

API Reference

generateKeyPair(): Promise<KeyPair>

Generate a new Ed25519 keypair.

signFeed(feed, privateKey, options?): Promise<SignedFeed>

Sign an LLMFeed with Ed25519.

Options:

• signedBlocks?: string[] - Blocks to include (default: all except trust/signature)
• publicKeyUrl?: string - URL for public_key_hint
• trustLevel?: string - Trust level descriptor
• addTimestamp?: boolean - Add created_at (default: true)

verifyFeed(feed, publicKey): Promise<VerificationResult>

Verify a signed feed's signature.

deepSortObject(obj): unknown

Deep sort object keys for canonical JSON.

License

MIT