update mcp definition example

etc.jl

@@ -1,5 +1,41 @@
-check my understand:
-1) if LLM didn't use tool calls, assistantMessage get pushed into agent._state.messages and 
-it will be the latest message in agent._state.messages. then _agentLoop() can pick it as 
-the output to outputChannel
-2) if LLM use tool calls but toolResultBatch.terminate is false, assistantMessageToolCall
+# "tools/list" input:
+mcpServer("tools/list")
+# sending out payload before smart packed by msghandler
+Dict(
+  "method"=> "tools/list"
+)
+# expected return after smart unpacked by msghandler
+Dict("tools" => [
+  Dict("toolName" => "getWeather",
+    "title" => "Weather Lookup",
+    "description" => "Fetch current weather for a city.",
+    "inputSchema" => Dict("type"=>"object",
+                          "properties" => Dict("city"=>Dict("type"=>"string", "description"=>"City name"),
+                                              "units"=>Dict("type"=>"string", "enum"=>["celsius","fahrenheit"], "default"=>"celsius")),
+                          "required" => ["city"])
+  )
+])
+
+# "tools/call" input:
+mcpServer("tools/call", "getWeather", Dict("city"=>"Tokyo", "units"=>"celsius"))
+# sending out payload before smart packed by msghandler
+Dict(
+  "method"=> "tools/call",
+  "tools"=> Dict("toolName"=>"getWeather", "arguments"=>Dict("city"=>"Tokyo", "units"=>"celsius"))
+)
+# expected return after smart unpacked by msghandler
+Dict(
+  "toolName"=>"getWeather",
+  "content": [{"type": "text", "text": "Weather in Tokyo: Sunny, 22°C"}],
+  "isError": false
+)
+
+# If an error occurs, mcpServer returns after smart unpacked by msghandler:
+Dict(
+  "toolName"=>"getWeather",
+  "content": [],
+  "error": Dict("code"=>1, "message"=>"City not found"),
+  "isError": true
+)
+
+