diff --git a/src/mcp/server/streamable_http_manager.py b/src/mcp/server/streamable_http_manager.py
index 3213eceff..964c52b6f 100644
--- a/src/mcp/server/streamable_http_manager.py
+++ b/src/mcp/server/streamable_http_manager.py
@@ -281,10 +281,7 @@ async def run_server(*, task_status: TaskStatus[None] = anyio.TASK_STATUS_IGNORE
             error_response = JSONRPCError(
                 jsonrpc="2.0",
                 id="server-error",
-                error=ErrorData(
-                    code=INVALID_REQUEST,
-                    message="Session not found",
-                ),
+                error=ErrorData(code=INVALID_REQUEST, message="Session not found"),
             )
             response = Response(
                 content=error_response.model_dump_json(by_alias=True, exclude_none=True),
diff --git a/src/mcp/server/validation.py b/src/mcp/server/validation.py
index 192b9d492..cfd663d43 100644
--- a/src/mcp/server/validation.py
+++ b/src/mcp/server/validation.py
@@ -50,12 +50,7 @@ def validate_sampling_tools(
     """
     if tools is not None or tool_choice is not None:
         if not check_sampling_tools_capability(client_caps):
-            raise McpError(
-                ErrorData(
-                    code=INVALID_PARAMS,
-                    message="Client does not support sampling tools capability",
-                )
-            )
+            raise McpError(ErrorData(code=INVALID_PARAMS, message="Client does not support sampling tools capability"))
 
 
 def validate_tool_use_result_messages(messages: list[SamplingMessage]) -> None:
diff --git a/src/mcp/shared/session.py b/src/mcp/shared/session.py
index e01167956..d00fd764c 100644
--- a/src/mcp/shared/session.py
+++ b/src/mcp/shared/session.py
@@ -7,7 +7,6 @@
 from typing import Any, Generic, Protocol, TypeVar
 
 import anyio
-import httpx
 from anyio.streams.memory import MemoryObjectReceiveStream, MemoryObjectSendStream
 from pydantic import BaseModel, TypeAdapter
 from typing_extensions import Self
@@ -18,6 +17,7 @@
 from mcp.types import (
     CONNECTION_CLOSED,
     INVALID_PARAMS,
+    REQUEST_TIMEOUT,
     CancelledNotification,
     ClientNotification,
     ClientRequest,
@@ -272,7 +272,7 @@ async def send_request(
             except TimeoutError:
                 raise McpError(
                     ErrorData(
-                        code=httpx.codes.REQUEST_TIMEOUT,
+                        code=REQUEST_TIMEOUT,
                         message=(
                             f"Timed out while waiting for response to {request.__class__.__name__}. "
                             f"Waited {timeout} seconds."
diff --git a/src/mcp/types/__init__.py b/src/mcp/types/__init__.py
index 25e821cc9..c4df66f8d 100644
--- a/src/mcp/types/__init__.py
+++ b/src/mcp/types/__init__.py
@@ -191,6 +191,7 @@
     INVALID_REQUEST,
     METHOD_NOT_FOUND,
     PARSE_ERROR,
+    REQUEST_TIMEOUT,
     URL_ELICITATION_REQUIRED,
     ErrorData,
     JSONRPCError,
@@ -402,6 +403,7 @@
     "INVALID_REQUEST",
     "METHOD_NOT_FOUND",
     "PARSE_ERROR",
+    "REQUEST_TIMEOUT",
     "URL_ELICITATION_REQUIRED",
     "ErrorData",
     "JSONRPCError",
diff --git a/src/mcp/types/jsonrpc.py b/src/mcp/types/jsonrpc.py
index eae3fc949..86066d80d 100644
--- a/src/mcp/types/jsonrpc.py
+++ b/src/mcp/types/jsonrpc.py
@@ -42,7 +42,7 @@ class JSONRPCResponse(BaseModel):
 
 # SDK error codes
 CONNECTION_CLOSED = -32000
-# REQUEST_TIMEOUT = -32001  # the typescript sdk uses this
+REQUEST_TIMEOUT = -32001
 
 # Standard JSON-RPC error codes
 PARSE_ERROR = -32700