Remove deprecated WSTransport (#2826)

docs/development/upgrade-guide.mdx

@@ -10,6 +10,10 @@ This guide provides migration instructions for breaking changes and major update
 
 ## v3.0.0
 
+### WSTransport Removed
+
+The deprecated `WSTransport` client transport has been removed. Use `StreamableHttpTransport` instead.
+
 ### Provider Architecture
 
 FastMCP v3 introduces a unified provider architecture for sourcing components. All tools, resources, and prompts now flow through providers:

docs/development/v3-notes/v3-features.mdx

@@ -304,6 +304,10 @@ The `tool_serializer` parameter on `FastMCP` is deprecated. Return `ToolResult`
 
 ## Breaking Changes
 
+### WSTransport Removed
+
+The deprecated `WSTransport` client transport has been removed. Use `StreamableHttpTransport` instead.
+
 ### Component Enable/Disable Moved to Server/Provider
 
 The `enabled` field and `enable()`/`disable()` methods removed from component objects:

src/fastmcp/client/__init__.py

@@ -1,18 +1,17 @@
+from .auth import OAuth, BearerAuth
 from .client import Client
 from .transports import (
     ClientTransport,
-    WSTransport,
+    FastMCPTransport,
+    NodeStdioTransport,
+    NpxStdioTransport,
+    PythonStdioTransport,
     SSETransport,
     StdioTransport,
-    PythonStdioTransport,
-    NodeStdioTransport,
-    UvxStdioTransport,
-    UvStdioTransport,
-    NpxStdioTransport,
-    FastMCPTransport,
     StreamableHttpTransport,
+    UvStdioTransport,
+    UvxStdioTransport,
 )
-from .auth import OAuth, BearerAuth
 
 __all__ = [
     "BearerAuth",
@@ -28,5 +27,4 @@ __all__ = [
     "StreamableHttpTransport",
     "UvStdioTransport",
     "UvxStdioTransport",
-    "WSTransport",
 ]

src/fastmcp/client/transports.py

@@ -119,45 +119,6 @@ class ClientTransport(abc.ABC):
             raise ValueError("This transport does not support auth")
 
 
-class WSTransport(ClientTransport):
-    """Transport implementation that connects to an MCP server via WebSockets."""
-
-    def __init__(self, url: str | AnyUrl):
-        # we never really used this transport, so it can be removed at any time
-        if fastmcp.settings.deprecation_warnings:
-            warnings.warn(
-                "WSTransport is a deprecated MCP transport and will be removed in a future version. Use StreamableHttpTransport instead.",
-                DeprecationWarning,
-                stacklevel=2,
-            )
-        if isinstance(url, AnyUrl):
-            url = str(url)
-        if not isinstance(url, str) or not url.startswith("ws"):
-            raise ValueError("Invalid WebSocket URL provided.")
-        self.url = url
-
-    @contextlib.asynccontextmanager
-    async def connect_session(
-        self, **session_kwargs: Unpack[SessionKwargs]
-    ) -> AsyncIterator[ClientSession]:
-        try:
-            from mcp.client.websocket import websocket_client
-        except ImportError as e:
-            raise ImportError(
-                "The websocket transport is not available. Please install fastmcp[websockets] or install the websockets package manually."
-            ) from e
-
-        async with websocket_client(self.url) as transport:
-            read_stream, write_stream = transport
-            async with ClientSession(
-                read_stream, write_stream, **session_kwargs
-            ) as session:
-                yield session
-
-    def __repr__(self) -> str:
-        return f"<WebSocketTransport(url='{self.url}')>"
-
-
 class SSETransport(ClientTransport):
     """Transport implementation that connects to an MCP server via Server-Sent Events."""