Recipe

Call the MCP server with JSON-RPC

Drive the public MCP server by hand with three JSON-RPC calls: initialize, tools/list, then tools/call on get_quote. No token, no SDK — just POSTs to /public/v1/mcp.

2 min read

JSON-RPC 2.0Over HTTP

3 callsinit/list/call

No tokenPublic ring

1. Initialize

curl -s -X POST https://hub.credicorp.co.uk/public/v1/mcp \
  -H 'Content-Type: application/json' \
  -d '{"jsonrpc":"2.0","id":1,"method":"initialize","params":{}}'

The result advertises the server's capabilities — see the endpoint reference.

2. List the tools

curl -s -X POST https://hub.credicorp.co.uk/public/v1/mcp \
  -H 'Content-Type: application/json' \
  -d '{"jsonrpc":"2.0","id":2,"method":"tools/list","params":{}}'

You get the six public tools with their input schemas — the catalogue.

3. Call get_quote

curl -s -X POST https://hub.credicorp.co.uk/public/v1/mcp \
  -H 'Content-Type: application/json' \
  -d '{"jsonrpc":"2.0","id":3,"method":"tools/call",
        "params":{"name":"get_quote",
          "arguments":{"product":"business_loan","amount":300,"term":30,"frequency":"weekly"}}}'

An out-of-range amount or term comes back as a JSON-RPC -32602 — see get_quote. To wrap this into an assistant, see building an application assistant.

Frequently asked questions

Do I need an MCP SDK?

No. MCP is JSON-RPC 2.0 over HTTP, so plain curl or any HTTP client works. An SDK is convenient for a real agent, but the protocol itself is just POSTing JSON.

What does the -32602 error mean?

It is the JSON-RPC invalid-params code. On get_quote it means your amount or term is out of the £50–£500 / 14–84-day range; the detail carries the bound so you can correct and retry.