Merge branch 'main' into decorators

docs/docs.json

@@ -12,7 +12,7 @@
         "decoration": "windows"
     },
     "banner": {
-        "content": "FastMCP Cloud is coming. [Claim your server](https://fastmcp.link/x0Kyhy2) today!"
+        "content": "[FastMCP Cloud](https://fastmcp.link/x0Kyhy2) is coming!"
     },
     "colors": {
         "dark": "#f72585",

pyproject.toml

@@ -11,7 +11,6 @@ dependencies = [
     "openapi-pydantic>=0.5.1",
     "rich>=13.9.4",
     "typer>=0.15.2",
-    "websockets>=14.0",
     "authlib>=1.5.2",
 ]
 requires-python = ">=3.10"
@@ -67,6 +66,9 @@ Homepage = "https://gofastmcp.com"
 Repository = "https://github.com/jlowin/fastmcp"
 Documentation = "https://gofastmcp.com"
 
+[project.optional-dependencies]
+websockets = ["websockets>=15.0.1"]
+
 
 [build-system]
 requires = ["hatchling", "uv-dynamic-versioning>=0.7.0"]

src/fastmcp/client/transports.py

@@ -27,10 +27,6 @@ from mcp.client.session import (
     MessageHandlerFnT,
     SamplingFnT,
 )
-from mcp.client.sse import sse_client
-from mcp.client.stdio import stdio_client
-from mcp.client.streamable_http import streamablehttp_client
-from mcp.client.websocket import websocket_client
 from mcp.server.fastmcp import FastMCP as FastMCP1Server
 from mcp.shared.memory import create_connected_server_and_client_session
 from pydantic import AnyUrl
@@ -141,6 +137,13 @@ class WSTransport(ClientTransport):
     async def connect_session(
         self, **session_kwargs: Unpack[SessionKwargs]
     ) -> AsyncIterator[ClientSession]:
+        try:
+            from mcp.client.websocket import websocket_client
+        except ImportError:
+            raise ImportError(
+                "The websocket transport is not available. Please install fastmcp[websockets] or install the websockets package manually."
+            )
+
         async with websocket_client(self.url) as transport:
             read_stream, write_stream = transport
             async with ClientSession(
@@ -188,6 +191,8 @@ class SSETransport(ClientTransport):
     async def connect_session(
         self, **session_kwargs: Unpack[SessionKwargs]
     ) -> AsyncIterator[ClientSession]:
+        from mcp.client.sse import sse_client
+
         client_kwargs: dict[str, Any] = {}
 
         # load headers from an active HTTP request, if available. This will only be true
@@ -255,6 +260,8 @@ class StreamableHttpTransport(ClientTransport):
     async def connect_session(
         self, **session_kwargs: Unpack[SessionKwargs]
     ) -> AsyncIterator[ClientSession]:
+        from mcp.client.streamable_http import streamablehttp_client
+
         client_kwargs: dict[str, Any] = {}
 
         # load headers from an active HTTP request, if available. This will only be true
@@ -350,6 +357,8 @@ class StdioTransport(ClientTransport):
             return
 
         async def _connect_task():
+            from mcp.client.stdio import stdio_client
+
             async with contextlib.AsyncExitStack() as stack:
                 try:
                     server_params = StdioServerParameters(

uv.lock

@@ -437,6 +437,10 @@ dependencies = [
     { name = "python-dotenv" },
     { name = "rich" },
     { name = "typer" },
+]
+
+[package.optional-dependencies]
+websockets = [
     { name = "websockets" },
 ]
 
@@ -473,8 +477,9 @@ requires-dist = [
     { name = "python-dotenv", specifier = ">=1.1.0" },
     { name = "rich", specifier = ">=13.9.4" },
     { name = "typer", specifier = ">=0.15.2" },
-    { name = "websockets", specifier = ">=14.0" },
+    { name = "websockets", marker = "extra == 'websockets'", specifier = ">=15.0.1" },
 ]
+provides-extras = ["websockets"]
 
 [package.metadata.requires-dev]
 dev = [