feat: google/adk-python#479 support for streamable http MCP servers for MCPToolset

Copybara import of the project:

--
c5b9d49d7b6d858ff0a93bd690e6d653b7c32221 by Omar BENHAMID <omar.benhamid@smart-gts.com>:

feat: google/adk-python#479 support for streamable http MCP servers for MCPToolset

--
9431bc19e6538c1b814aba0b24ff564acf046075 by Omar BENHAMID <omar.benhamid@smart-gts.com>:

feat: google/adk-python#479 streamable http added to right package

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8b4aabed45a6f0dc828beb61f12985dc7b14f3d0 by Omar BENHAMID <omar.benhamid@smart-gts.com>:

feat: google/adk-python#479 streamable http : review feedbacks + sample agent
COPYBARA_INTEGRATE_REVIEW=https://github.com/google/adk-python/pull/650 from omarbenhamid:feature/mcp-streamable-http 625f028784c216401d45cb1b5d4d998535ebcb00
PiperOrigin-RevId: 764419586

src/google/adk/tools/mcp_tool/mcp_session_manager.py

@@ -17,10 +17,10 @@ from contextlib import AsyncExitStack
 import functools
 import logging
 import sys
+from datetime import timedelta
 from typing import Any
 from typing import Optional
 from typing import TextIO
-
 import anyio
 from pydantic import BaseModel
 
@@ -29,6 +29,7 @@ try:
   from mcp import StdioServerParameters
   from mcp.client.sse import sse_client
   from mcp.client.stdio import stdio_client
+  from mcp.client.streamable_http import streamablehttp_client
 except ImportError as e:
   import sys
 
@@ -56,6 +57,19 @@ class SseServerParams(BaseModel):
   sse_read_timeout: float = 60 * 5
 
 
+class StreamableHTTPServerParams(BaseModel):
+  """Parameters for the MCP SSE connection.
+
+  See MCP SSE Client documentation for more details.
+  https://github.com/modelcontextprotocol/python-sdk/blob/main/src/mcp/client/streamable_http.py
+  """
+  url: str
+  headers: dict[str, Any] | None = None
+  timeout: float = 5
+  sse_read_timeout: float = 60 * 5
+  terminate_on_close: bool = True
+
+
 def retry_on_closed_resource(async_reinit_func_name: str):
   """Decorator to automatically reinitialize session and retry action.
 
@@ -123,13 +137,13 @@ class MCPSessionManager:
 
   def __init__(
       self,
-      connection_params: StdioServerParameters | SseServerParams,
+      connection_params: StdioServerParameters | SseServerParams | StreamableHTTPServerParams,
       errlog: TextIO = sys.stderr,
   ):
     """Initializes the MCP session manager.
 
     Args:
-        connection_params: Parameters for the MCP connection (Stdio or SSE).
+        connection_params: Parameters for the MCP connection (Stdio, SSE or Streamable HTTP).
         errlog: (Optional) TextIO stream for error logging. Use only for
           initializing a local stdio MCP session.
     """
@@ -163,6 +177,14 @@ class MCPSessionManager:
             timeout=self._connection_params.timeout,
             sse_read_timeout=self._connection_params.sse_read_timeout,
         )
+      elif isinstance(self._connection_params, StreamableHTTPServerParams):
+        client = streamablehttp_client(
+            url=self._connection_params.url,
+            headers=self._connection_params.headers,
+            timeout=timedelta(seconds=self._connection_params.timeout),
+            sse_read_timeout=timedelta(seconds=self._connection_params.sse_read_timeout),
+            terminate_on_close=self._connection_params.terminate_on_close,
+        )
       else:
         raise ValueError(
             'Unable to initialize connection. Connection should be'
@@ -171,8 +193,10 @@ class MCPSessionManager:
         )
 
       transports = await self._exit_stack.enter_async_context(client)
+      # The streamable http client returns a GetSessionCallback in addition to the read/write MemoryObjectStreams
+      # needed to build the ClientSession, we limit then to the two first values to be compatible with all clients.
       session = await self._exit_stack.enter_async_context(
-          ClientSession(*transports)
+          ClientSession(*transports[:2])
       )
       await session.initialize()
 

src/google/adk/tools/mcp_tool/mcp_toolset.py

@@ -26,6 +26,7 @@ from ..base_toolset import ToolPredicate
 from .mcp_session_manager import MCPSessionManager
 from .mcp_session_manager import retry_on_closed_resource
 from .mcp_session_manager import SseServerParams
+from .mcp_session_manager import StreamableHTTPServerParams
 
 # Attempt to import MCP Tool from the MCP library, and hints user to upgrade
 # their Python version to 3.10 if it fails.
@@ -82,17 +83,18 @@ class MCPToolset(BaseToolset):
   def __init__(
       self,
       *,
-      connection_params: StdioServerParameters | SseServerParams,
+      connection_params: StdioServerParameters | SseServerParams | StreamableHTTPServerParams,
       tool_filter: Optional[Union[ToolPredicate, List[str]]] = None,
       errlog: TextIO = sys.stderr,
   ):
     """Initializes the MCPToolset.
 
     Args:
-        connection_params: The connection parameters to the MCP server. Can be:
-            `StdioServerParameters` for using local mcp server (e.g. using `npx` or
-            `python3`); or `SseServerParams` for a local/remote SSE server.
-        tool_filter: Optional filter to select specific tools. Can be either:
+      connection_params: The connection parameters to the MCP server. Can be:
+        `StdioServerParameters` for using local mcp server (e.g. using `npx` or
+        `python3`); or `SseServerParams` for a local/remote SSE server; or
+        `StreamableHTTPServerParams` for local/remote Streamable http server.
+      tool_filter: Optional filter to select specific tools. Can be either:
             - A list of tool names to include
             - A ToolPredicate function for custom filtering logic
         errlog: TextIO stream for error logging.
@@ -110,6 +112,7 @@ class MCPToolset(BaseToolset):
         connection_params=self._connection_params,
         errlog=self._errlog,
     )
+
     self._session = None
 
   @retry_on_closed_resource("_reinitialize_session")