diff --git a/src/typed.jl b/src/typed.jl
index e080d81e..22dc030b 100644
--- a/src/typed.jl
+++ b/src/typed.jl
@@ -59,10 +59,24 @@ function dispatch_msg(x::JSONRPCEndpoint, dispatcher::MsgDispatcher, msg::Reques
     dispatcher._currentlyHandlingMsg = true
     try
         method_name = msg.method
+        is_request = msg.id !== nothing
         handler = get(dispatcher._handlers, method_name, nothing)
         if handler !== nothing
             param_type = get_param_type(handler.message_type)
-            params = param_type === Nothing ? nothing : param_type <: NamedTuple ? convert(param_type,(;(Symbol(i[1])=>i[2] for i in msg.params)...)) : param_type(msg.params)
+            params = try
+                if param_type === Nothing
+                    nothing
+                elseif param_type <: NamedTuple
+                    convert(param_type,(;(Symbol(i[1])=>i[2] for i in msg.params)...))
+                else
+                    param_type(msg.params)
+                end
+            catch err
+                if is_request
+                    send_error_response(x, msg, INVALID_PARAMS, "Failed to parse parameters.", nothing)
+                end
+                rethrow(err)
+            end
 
             if handler.message_type isa RequestType
                 res = handler.func(x, params, msg.token)
@@ -82,6 +96,9 @@ function dispatch_msg(x::JSONRPCEndpoint, dispatcher::MsgDispatcher, msg::Reques
                 end
             end
         else
+            if is_request
+                send_error_response(x, msg, METHOD_NOT_FOUND, "Unknown method '$method_name'.", nothing)
+            end
             error("Unknown method $method_name.")
         end
     finally
@@ -95,13 +112,27 @@ macro message_dispatcher(name, body)
     quote
         function $(esc(name))(x, msg::Request, context=nothing)
             method_name = msg.method
+            is_request = msg.id !== nothing
 
             $(
                 (
                     :(
                         if method_name == $(esc(i.args[2])).method
                             param_type = get_param_type($(esc(i.args[2])))
-                            params = param_type === Nothing ? nothing : param_type <: NamedTuple ? convert(param_type,(;(Symbol(i[1])=>i[2] for i in msg.params)...)) : param_type(msg.params)
+                            params = try
+                                if param_type === Nothing
+                                    nothing
+                                elseif param_type <: NamedTuple
+                                    convert(param_type,(;(Symbol(i[1])=>i[2] for i in msg.params)...))
+                                else
+                                    param_type(msg.params)
+                                end
+                            catch err
+                                if is_request
+                                    send_error_response(x, msg, INVALID_PARAMS, "Failed to parse parameters.", nothing)
+                                end
+                                rethrow(err)
+                            end
 
                             if context===nothing
                                 if $(esc(i.args[2])) isa RequestType
@@ -135,6 +166,10 @@ macro message_dispatcher(name, body)
                 )...
             )
 
+            if is_request
+                send_error_response(x, msg, METHOD_NOT_FOUND, "Unknown method '$method_name'.", nothing)
+            end
+            
             error("Unknown method $method_name.")
         end
     end