rpc_call
Call any JSON-RPC method on a server with parameters. A user would prompt: Call method <method> on <server url> with params <params>
LABSCO SUMMARY
A JSON-RPC endpoint becomes callable without a wrapper written for it first.
rpc_discover is what makes the pair worth installing: an OpenRPC-compliant server describes its own methods, so the next call is composed from that answer instead of from a README. Against a server that does not implement rpc.discover you are left with rpc_call and the method names you already knew.
What it is
A two-tool JSON-RPC client: rpc_discover for the method list a server describes about itself, rpc_call for any method on it.
What you get
- rpc_discover calling rpc.discover from the OpenRPC specification, so the method list comes from the server rather than from documentation
- rpc_call against any method on any reachable server URL, with params passed straight through
- The two in order — discover the surface, then work it — without a client library written for that particular API
Requirements
The URL of a JSON-RPC server you can reach, and for the discovery call, one that implements rpc.discover. Apache-2.0 licensed.
Setup effort
One command — npx -y openrpc-mcp-server
USE CASES
01
Working against an RPC endpoint you have never called
Ask the server what it exposes, then call the method that looks right with the parameters its own description gave you — no client library in between.
02
Checking what a node exposes before writing any code
Point discovery at the endpoint and read the method list, which settles whether the integration is worth starting before a line of it exists.
2 tools
Counted once with only startup setup. Other versions, modes or optional credentials may expose a different list.
rpc_discover
This uses JSON-RPC to call rpc.discover which is part of the OpenRPC Specification for discovery for JSON-RPC servers. A user would prompt: What JSON-RPC methods does this server have? <server url>
BEFORE YOU INSTALL
What to know first
Tools you get
2 tools when we connected.
Requires
npx on PATH
CONTEXT COST
Light Standing cost
Rated by the size of the 2 tool definitions that ride along on every turn, not by how many there are
INSTALLATION
Connect your client
Add the block to your client, or run the command directly.
Server setup
Configuration file
JSON
{
"mcpServers": {
"openrpc-mcp-server": {
"command": "npx",
"args": [
"-y",
"openrpc-mcp-server"
]
}
}
}npx
TERMINAL
npx -y openrpc-mcp-server
