When a proto file is loaded with @grpc/proto-loaded the method names are UpperCamelCase and a property called originalName is added to the method definition that has the lowerCamelCase name.

The client constructor in the grpc module creates a method alias using the originalName.

The problem is the alias is created before the methods are patched, so you can use both to make gRPC calls but only the UpperCamelCase method is traced.

import { loadSync } from "@grpc/proto-loader";
import grpc from "grpc";

const credentials = grpc.credentials.createInsecure();

const packageDefinition = loadSync("myservice.proto");
const descriptor = grpc.loadPackageDefinition(packageDefinition);
const client = new descriptor.mypackage.ApiTokenService("0.0.0.0:50051", credentials);

console.log(client.MyMethod);
console.log(client.myMethod);

Only client.MyMethod uses clientMethodTrace.