Support for proxy in SSE and Streamable client.

Author: DebajitKumarPhukan

src/mcp/client/sse.py

@@ -1,6 +1,6 @@
 import logging
 from contextlib import asynccontextmanager
-from typing import Any
+from typing import Any, Optional
 from urllib.parse import urljoin, urlparse
 
 import anyio
@@ -28,6 +28,7 @@ async def sse_client(
     sse_read_timeout: float = 60 * 5,
     httpx_client_factory: McpHttpClientFactory = create_mcp_http_client,
     auth: httpx.Auth | None = None,
+    proxy: Optional[str] = None
 ):
     """
     Client transport for SSE.
@@ -55,7 +56,7 @@ async def sse_client(
         try:
             logger.debug(f"Connecting to SSE endpoint: {remove_request_params(url)}")
             async with httpx_client_factory(
-                headers=headers, auth=auth, timeout=httpx.Timeout(timeout, read=sse_read_timeout)
+                headers=headers, auth=auth, timeout=httpx.Timeout(timeout, read=sse_read_timeout), proxy=proxy
             ) as client:
                 async with aconnect_sse(
                     client,

src/mcp/client/streamable_http.py

@@ -11,6 +11,7 @@
 from contextlib import asynccontextmanager
 from dataclasses import dataclass
 from datetime import timedelta
+from typing import Optional
 
 import anyio
 import httpx
@@ -448,6 +449,7 @@ async def streamablehttp_client(
     terminate_on_close: bool = True,
     httpx_client_factory: McpHttpClientFactory = create_mcp_http_client,
     auth: httpx.Auth | None = None,
+    proxy: Optional[str] = None
 ) -> AsyncGenerator[
     tuple[
         MemoryObjectReceiveStream[SessionMessage | Exception],
@@ -481,6 +483,7 @@ async def streamablehttp_client(
                 headers=transport.request_headers,
                 timeout=httpx.Timeout(transport.timeout, read=transport.sse_read_timeout),
                 auth=transport.auth,
+                proxy=proxy
             ) as client:
                 # Define callbacks that need access to tg
                 def start_get_stream() -> None:

src/mcp/shared/_httpx_utils.py

@@ -1,6 +1,6 @@
 """Utilities for creating standardized httpx AsyncClient instances."""
 
-from typing import Any, Protocol
+from typing import Any, Optional, Protocol
 
 import httpx
 
@@ -13,13 +13,15 @@ def __call__(
         headers: dict[str, str] | None = None,
         timeout: httpx.Timeout | None = None,
         auth: httpx.Auth | None = None,
+        proxy: Optional[str] | None = None
     ) -> httpx.AsyncClient: ...
 
 
 def create_mcp_http_client(
     headers: dict[str, str] | None = None,
     timeout: httpx.Timeout | None = None,
     auth: httpx.Auth | None = None,
+    proxy: Optional[str] | None = None
 ) -> httpx.AsyncClient:
     """Create a standardized httpx AsyncClient with MCP defaults.
 
@@ -80,4 +82,8 @@ def create_mcp_http_client(
     if auth is not None:
         kwargs["auth"] = auth
 
+    # Configure proxy if applied
+    if proxy is not None:
+        kwargs["proxy"] = proxy
+
     return httpx.AsyncClient(**kwargs)