Invalid protocol request

A message does not satisfy JSON-RPC framing or the host's object-parameter requirement, so the request is rejected. This code also represents a refused non-local browser origin, or wraps an external RPC error that supplied no structured Ara diagnostics; read its message for that underlying failure.

#Common causes

• A missing jsonrpc: "2.0", invalid message shape or non-object method parameters.
• An HTTP request has a browser origin outside the allowed loopback hosts.
• A transport or foreign server returned an error without data.diagnostics.

#Fixes

• Send a JSON-RPC 2.0 object with a method name and object params, using rpc.discover for the method's schema.

• Use ara mcp or the supported authenticated local endpoint for local clients; diagnose the underlying transport message when this code wraps another error.

• Code: ARA1801

• Constant: INVALID_REQUEST

• Reported by: ara-proto, ara-host, ara-rpc