Add uvx client

src/fastmcp/client/stdio.py

@@ -1,4 +1,6 @@
 import contextlib
+import os
+from typing import Dict, List, Optional
 
 from mcp import ClientSession, StdioServerParameters
 from mcp.client.stdio import stdio_client
@@ -39,3 +41,95 @@ class StdioClient(BaseClient):
             ) as session:
                 async with self._set_session(transport, session):
                     yield self
+
+
+class UvxClient(BaseClient):
+    """Client that uses uvx to run Python tools in isolated environments.
+
+    uvx automatically installs and manages dependencies from pyproject.toml.
+    """
+
+    def __init__(
+        self,
+        tool_name: str,
+        tool_args: Optional[List[str]] = None,
+        project_directory: Optional[str] = None,
+        python_version: Optional[str] = None,
+        with_packages: Optional[List[str]] = None,
+        from_package: Optional[str] = None,
+        env_vars: Optional[Dict[str, str]] = None,
+        **kwargs: Unpack[ClientKwargs],
+    ):
+        """Initialize a UvxClient that uses uvx to run Python tools in isolated environments.
+
+        Args:
+            tool_name: Name of the tool/command to run
+            tool_args: Arguments to pass to the tool
+            project_directory: Path to the project directory (optional)
+            python_version: Specific Python version to use (e.g., "3.10")
+            with_packages: Additional packages to include
+            from_package: Package that provides the tool if different from tool_name
+            env_vars: Environment variables to set for the process
+            **kwargs: Additional arguments for BaseClient
+        """
+        super().__init__(**kwargs)
+        self.tool_name = tool_name
+        self.tool_args = tool_args or []
+        self.project_directory = project_directory
+        self.python_version = python_version
+        self.with_packages = with_packages or []
+        self.from_package = from_package
+        self.env_vars = env_vars or {}
+
+    @contextlib.asynccontextmanager
+    async def _connect(self):
+        """Set up uvx connection and session"""
+        # Check if project directory exists if provided
+        if self.project_directory and not os.path.isdir(self.project_directory):
+            raise ValueError(
+                f"Project directory does not exist: {self.project_directory}"
+            )
+
+        # Build the uvx command arguments
+        args = []
+
+        # Add Python version if specified
+        if self.python_version:
+            args.extend(["--python", self.python_version])
+
+        # Add from package if specified
+        if self.from_package:
+            args.extend(["--from", self.from_package])
+
+        # Add with packages if specified
+        for pkg in self.with_packages:
+            args.extend(["--with", pkg])
+
+        # Add the tool name
+        args.append(self.tool_name)
+
+        # Add the tool arguments
+        args.extend(self.tool_args)
+
+        # Create environment variables dictionary
+        env = os.environ.copy()
+        env.update(self.env_vars)
+
+        # Configure the server parameters
+        server_params = StdioServerParameters(
+            command="uvx",
+            args=args,
+            env=env,
+            cwd=self.project_directory,
+        )
+
+        async with stdio_client(server_params) as transport:
+            stdio, write = transport
+
+            async with ClientSession(
+                read_stream=stdio,
+                write_stream=write,
+                **self._session_kwargs(),
+            ) as session:
+                async with self._set_session(transport, session):
+                    yield self