Quick Start

Public MCP is an MCP server that requires no authentication: give it a Caoliao QR code and the agent learns what is behind it — the equipment, its state, its history, and what can be done with it right now.

No account, no application process. Set the URL and it works.

Service details

Item	Value
Endpoint	https://mcp.objqr.com/mcp
Transport	Streamable HTTP
Server name	im.cli/qrcode
Tools	5, all read-only
Authentication	None (public data by default; for authorized reads see Data Scope and Authorization)

Client configuration

Most MCP clients use the same configuration shape. For Claude Desktop and Cursor, add:

{
  "mcpServers": {
    "caoliao": {
      "type": "http",
      "url": "https://mcp.objqr.com/mcp"
    }
  }
}

Note: Claude Desktop's configuration file opens from Settings → Developer → Edit Config (claude_desktop_config.json); in Cursor, add it under Settings → MCP or edit .cursor/mcp.json in your project. Field names vary between other clients (some use transport, others type) — follow your client's documentation. The URL is the same either way.

Restart the client afterwards; five tools prefixed with entity_ will appear in the tool list.

Verify with curl

You can verify without installing a client. The request must accept both JSON and SSE.

Handshake:

curl -X POST https://mcp.objqr.com/mcp \
  -H 'content-type: application/json' \
  -H 'accept: application/json, text/event-stream' \
  -d '{
    "jsonrpc": "2.0",
    "id": 1,
    "method": "initialize",
    "params": {
      "protocolVersion": "2025-06-18",
      "capabilities": {},
      "clientInfo": { "name": "demo", "version": "0" }
    }
  }'

Response:

event: message
data: {"result":{"protocolVersion":"2025-06-18","capabilities":{"tools":{},"logging":{},"completions":{}},"serverInfo":{"name":"im.cli/qrcode","version":"0.1.0"}},"jsonrpc":"2.0","id":1}

Note: the actual output also has an id: line (the SSE event id) between event: and data: — you can ignore it.

Query a QR code:

curl -X POST https://mcp.objqr.com/mcp \
  -H 'content-type: application/json' \
  -H 'accept: application/json, text/event-stream' \
  -d '{
    "jsonrpc": "2.0",
    "id": 2,
    "method": "tools/call",
    "params": {
      "name": "entity_get",
      "arguments": { "code": "https://qr71.cn/okDISU/qssTnoy" }
    }
  }'

The response carries the equipment name, properties, current state, record count and available actions for that code. Note that the live service returns field values in Chinese; the examples in Tools are translated for illustration. Full field reference there.

What to ask first

Start with entity_get. It returns the whole entity in one call, including previews of actions and records. Then decide whether to go deeper:

• Need the full history → entity_records_list
• Need to know what can be done now → entity_actions_list
• Need the fields of a specific action → entity_action_get

Next

• Tools — parameters and responses for all five tools
• Data Scope and Authorization — what you read by default, and what a credential adds