session_id added to message

src/mcp/server/lowlevel/server.py

@@ -221,8 +221,8 @@ def list_prompts(self):
         def decorator(func: Callable[[], Awaitable[list[types.Prompt]]]):
             logger.debug("Registering handler for PromptListRequest")
 
-            async def handler(_: Any):
-                prompts = await func()
+            async def handler(request: types.ListPromptsRequest):
+                prompts = await func(request)
                 return types.ServerResult(types.ListPromptsResult(prompts=prompts))
 
             self.request_handlers[types.ListPromptsRequest] = handler
@@ -251,8 +251,8 @@ def list_resources(self):
         def decorator(func: Callable[[], Awaitable[list[types.Resource]]]):
             logger.debug("Registering handler for ListResourcesRequest")
 
-            async def handler(_: Any):
-                resources = await func()
+            async def handler(request: types.ListResourcesRequest):
+                resources = await func(request)
                 return types.ServerResult(
                     types.ListResourcesResult(resources=resources)
                 )
@@ -266,8 +266,8 @@ def list_resource_templates(self):
         def decorator(func: Callable[[], Awaitable[list[types.ResourceTemplate]]]):
             logger.debug("Registering handler for ListResourceTemplatesRequest")
 
-            async def handler(_: Any):
-                templates = await func()
+            async def handler(request: types.ListResourceTemplatesRequest):
+                templates = await func(request)
                 return types.ServerResult(
                     types.ListResourceTemplatesResult(resourceTemplates=templates)
                 )
@@ -383,8 +383,8 @@ def list_tools(self):
         def decorator(func: Callable[[], Awaitable[list[types.Tool]]]):
             logger.debug("Registering handler for ListToolsRequest")
 
-            async def handler(_: Any):
-                tools = await func()
+            async def handler(request: types.ListToolsRequest):
+                tools = await func(request)
                 return types.ServerResult(types.ListToolsResult(tools=tools))
 
             self.request_handlers[types.ListToolsRequest] = handler

src/mcp/server/sse.py

@@ -32,6 +32,7 @@ async def handle_sse(request):
 """
 
 import logging
+import json
 from contextlib import asynccontextmanager
 from typing import Any
 from urllib.parse import quote
@@ -160,7 +161,11 @@ async def handle_post_message(
         logger.debug(f"Received JSON: {body}")
 
         try:
-            message = types.JSONRPCMessage.model_validate_json(body)
+            message_with_session_id = {
+                **json.loads(body),
+                'session_id': str(session_id),
+            }
+            message = types.JSONRPCMessage.model_validate_json(json.dumps(message_with_session_id))
             logger.debug(f"Validated client message: {message}")
         except ValidationError as err:
             logger.error(f"Failed to parse message: {err}")