Yes more debug logging.

src/node-capnp/capnp.cc

@@ -2456,6 +2456,17 @@ v8::Handle<v8::Value> enableVerboseDebugLogging(const v8::Arguments& args) {
   });
 }
 
+v8::Handle<v8::Value> methodName(const v8::Arguments& args) {
+  // methodName(method) -> string
+
+  KJV8_UNWRAP(CapnpContext, context, args.Data());
+  KJV8_UNWRAP(capnp::InterfaceSchema::Method, method, args[0]);
+
+  return liftKj([&]() -> v8::Handle<v8::Value> {
+    return v8::String::NewSymbol(method.getProto().getName().cStr());
+  });
+}
+
 // -----------------------------------------------------------------------------
 
 void init(v8::Handle<v8::Object> exports) {
@@ -2502,6 +2513,7 @@ void init(v8::Handle<v8::Object> exports) {
     mapFunction("throw_", throw_);
 
     mapFunction("enableVerboseDebugLogging", enableVerboseDebugLogging);
+    mapFunction("methodName", methodName);
 
     return emptyHandle;
   });

src/node-capnp/capnp.js

@@ -153,12 +153,23 @@ function makeMethod(cap, method) {
     v8capnp.fromJs(req, Array.prototype.slice.call(arguments, 0), LocalCapWrapper);
     var pipeline;
     var promise = new Promise(function (resolve, reject) {
-      pipeline = v8capnp.send(req, resolve, reject, Capability);
+      pipeline = v8capnp.send(req, function (x) {
+        if (verboseDebugLogging) console.log("capnp.js: returned to JS 1", v8capnp.methodName(method));
+        resolve(x);
+      }, function (x) {
+        if (verboseDebugLogging) console.log("capnp.js: threw to JS 1", v8capnp.methodName(method), x);
+        reject(x);
+      }, Capability);
     }).then(function (response) {
+      if (verboseDebugLogging) console.log("capnp.js: returned to JS 2", v8capnp.methodName(method));
       var result = v8capnp.toJs(response, Capability);
       v8capnp.release(response);
       settleCaps(pipeline, result);
+      if (verboseDebugLogging) console.log("capnp.js: returned to JS 3", v8capnp.methodName(method));
       return result;
+    }, function (err) {
+      if (verboseDebugLogging) console.log("capnp.js: threw to JS 2", v8capnp.methodName(method));
+      throw err;
     });
     makeRemotePromise(promise, pipeline);
     return promise;
@@ -276,4 +287,8 @@ exports.bytesToPreorder = function(schema, buf) {
   return v8capnp.toBytes(builder);
 }
 
-exports.enableVerboseDebugLogging = v8capnp.enableVerboseDebugLogging;
+var verboseDebugLogging = false;
+exports.enableVerboseDebugLogging = function (flag) {
+  verboseDebugLogging = flag;
+  v8capnp.enableVerboseDebugLogging(flag);
+}