MCP JSON Sanitizer

Remote MCP server on Cloudflare Workers that repairs malformed JSON strings into valid JSON for agent workflows.

What It Does

json_sanitizer accepts a string that is supposed to be JSON but may have common LLM formatting issues. The Worker applies deterministic cleanup steps and returns valid JSON when recovery succeeds.

Handled fixes include:

• code fence removal
• smart quote normalization
• extraction of the JSON body from surrounding prose
• quoting bare object keys
• conversion of single-quoted strings
• trailing comma removal
• closing missing } and ]

Tool

json_sanitizer

Input:

• input: malformed JSON-like string
• pretty?: pretty-print output JSON, defaults to true

Output:

• repaired JSON text
• structured metadata with applied fixes and parsed JSON value

Transport

• MCP endpoint: https://<your-worker>.workers.dev/mcp
• Well-known manifest: https://<your-worker>.workers.dev/.well-known/mcp/server.json
• Health check: https://<your-worker>.workers.dev/health

Monetization

Only actual tool execution requires payment:

• free: GET /mcp, tools/list, initialize, ping
• paid: tools/call for json_sanitizer

Payment settings:

• network: eip155:8453 (Base)
• asset: USDC
• price: 0.001
• payTo: 0x4505A361611DebB4928Db488ad7E345cD5821cD4

Deploy

1. Install dependencies with npm install.
2. Authenticate Wrangler with npx wrangler login.
3. Set the settlement signer privately with npx wrangler secret put EVM_PRIVATE_KEY.
4. Update PUBLIC_BASE_URL in wrangler.toml to your final Worker URL.
5. Deploy with npm run deploy.