fix: align timeout params between sse_client and streamable_http_client

Fixes #936

- sse_client: replace hardcoded timeout defaults (5.0/300.0) with shared
  constants MCP_DEFAULT_TIMEOUT and MCP_DEFAULT_SSE_READ_TIMEOUT
- streamable_http_client: add headers, timeout, sse_read_timeout, and auth
  parameters to match sse_client's interface
- Both transports now use consistent defaults from _httpx_utils.py

Author: mritunjaypratapsingh

src/mcp/client/sse.py

@@ -12,7 +12,12 @@
 from httpx_sse._exceptions import SSEError
 
 from mcp import types
-from mcp.shared._httpx_utils import McpHttpClientFactory, create_mcp_http_client
+from mcp.shared._httpx_utils import (
+    MCP_DEFAULT_SSE_READ_TIMEOUT,
+    MCP_DEFAULT_TIMEOUT,
+    McpHttpClientFactory,
+    create_mcp_http_client,
+)
 from mcp.shared.message import SessionMessage
 
 logger = logging.getLogger(__name__)
@@ -31,8 +36,8 @@ def _extract_session_id_from_endpoint(endpoint_url: str) -> str | None:
 async def sse_client(
     url: str,
     headers: dict[str, Any] | None = None,
-    timeout: float = 5.0,
-    sse_read_timeout: float = 300.0,
+    timeout: float = MCP_DEFAULT_TIMEOUT,
+    sse_read_timeout: float = MCP_DEFAULT_SSE_READ_TIMEOUT,
     httpx_client_factory: McpHttpClientFactory = create_mcp_http_client,
     auth: httpx.Auth | None = None,
     on_session_created: Callable[[str], None] | None = None,

src/mcp/client/streamable_http.py

@@ -16,7 +16,7 @@
 from pydantic import ValidationError
 
 from mcp.client._transport import TransportStreams
-from mcp.shared._httpx_utils import create_mcp_http_client
+from mcp.shared._httpx_utils import MCP_DEFAULT_SSE_READ_TIMEOUT, MCP_DEFAULT_TIMEOUT, create_mcp_http_client
 from mcp.shared.message import ClientMessageMetadata, SessionMessage
 from mcp.types import (
     INTERNAL_ERROR,
@@ -513,16 +513,26 @@ def get_session_id(self) -> str | None:
 async def streamable_http_client(
     url: str,
     *,
+    headers: dict[str, str] | None = None,
+    timeout: float = MCP_DEFAULT_TIMEOUT,
+    sse_read_timeout: float = MCP_DEFAULT_SSE_READ_TIMEOUT,
+    auth: httpx.Auth | None = None,
     http_client: httpx.AsyncClient | None = None,
     terminate_on_close: bool = True,
 ) -> AsyncGenerator[TransportStreams, None]:
     """Client transport for StreamableHTTP.
 
+    `sse_read_timeout` determines how long (in seconds) the client will wait for a new
+    event before disconnecting. All other HTTP operations are controlled by `timeout`.
+
     Args:
         url: The MCP server endpoint URL.
-        http_client: Optional pre-configured httpx.AsyncClient. If None, a default
-            client with recommended MCP timeouts will be created. To configure headers,
-            authentication, or other HTTP settings, create an httpx.AsyncClient and pass it here.
+        headers: Optional headers to include in requests.
+        timeout: HTTP timeout for regular operations (in seconds).
+        sse_read_timeout: Timeout for SSE read operations (in seconds).
+        auth: Optional HTTPX authentication handler.
+        http_client: Optional pre-configured httpx.AsyncClient. If provided, `headers`,
+            `timeout`, `sse_read_timeout`, and `auth` are ignored.
         terminate_on_close: If True, send a DELETE request to terminate the session when the context exits.
 
     Yields:
@@ -542,7 +552,11 @@ async def streamable_http_client(
 
     if client is None:
         # Create default client with recommended MCP timeouts
-        client = create_mcp_http_client()
+        client = create_mcp_http_client(
+            headers=headers,
+            timeout=httpx.Timeout(timeout, read=sse_read_timeout),
+            auth=auth,
+        )
 
     transport = StreamableHTTPTransport(url)