Fix stdio bugs (#608)

1. Updates `arcade configure claude --from-local` to create a valid json
config for claude desktop. NOTE: The `arcade configure` command needs
some re-work. It's fragile.
2. Fixes bug where stdio servers were sending logs to the wrong sink.
3. Disabled colorized logs for stdio.
4. Added missing dependency `httpx` for servers created with `arcade
new`

## Claude Desktop json configuration for stdio
Personally I like option 1 because the configuration looks the simplest
### Option 1:
Equivalent to `python server.py stdio`
```
{
  "globalShortcut": "Alt+Ctrl+Space",
  "mcpServers": {
    "my_server": {
      "command": "/path/to/my/mcp/server/directory/.venv/bin/python",
      "args": [
        "/path/to/my/mcp/server/directory/server.py",
        "stdio"
      ]
    }
  }
}
```
### Option 2:
Equivalent to `uv run server.py stdio`
```
{
  "mcpServers": {
    "my_server": {
      "command": "uv",
      "args": [
        "run",
        "--directory",
        "/path/to/my/mcp/server/directory",
        "python",
        "server.py",
        "stdio"
      ]
    }
  }
}
```
### Option 3:
Equivalent to `python -m arcade_mcp_server stdio --cwd ./`
```
{
  "mcpServers": {
    "my_server": {
      "command": "/path/to/my/mcp/server/directory/.venv/bin/python",
      "args": [
        "-m",
        "arcade_mcp_server",
        "stdio",
        "--cwd",
        "/path/to/my/mcp/server/directory"
      ]
    }
  }
}
```

libs/arcade-cli/arcade_cli/configure.py

@@ -56,6 +56,26 @@ def configure_claude_local(server_name: str, port: int = 8000, path: Path | None
     config_path = path or get_claude_config_path()
     config_path.parent.mkdir(parents=True, exist_ok=True)
 
+    # Assume server.py is the entry point for the server
+    server_file = Path.cwd() / "server.py"
+
+    # Find the Python interpreter in the virtual environment
+    venv_python = None
+    # Check for .venv first (uv default)
+    if (Path.cwd() / ".venv").exists():
+        system = platform.system()
+        if system == "Windows":
+            venv_python = Path.cwd() / ".venv" / "Scripts" / "python.exe"
+        else:
+            venv_python = Path.cwd() / ".venv" / "bin" / "python"
+
+    # Fall back to system python if no venv found
+    if not venv_python or not venv_python.exists():
+        console.print("[yellow]Warning: No .venv found, using system python[/yellow]")
+        import sys
+
+        venv_python = Path(sys.executable)
+
     # Load existing config or create new one
     config = {}
     if config_path.exists():
@@ -66,10 +86,10 @@ def configure_claude_local(server_name: str, port: int = 8000, path: Path | None
     if "mcpServers" not in config:
         config["mcpServers"] = {}
 
+    # Claude Desktop uses stdio transport
     config["mcpServers"][server_name] = {
-        "command": "python",
+        "command": str(venv_python),
-        "args": ["-m", "arcade_mcp_server", "stream"],
+        "args": [str(server_file), "stdio"],
-        "url": f"http://localhost:{port}/mcp",
     }
 
     # Write updated config
@@ -82,7 +102,8 @@ def configure_claude_local(server_name: str, port: int = 8000, path: Path | None
     )
     config_file_path = config_path.as_posix().replace(" ", "\\ ")
     console.print(f"   MCP client config file: {config_file_path}", style="dim")
-    console.print(f"   MCP Server URL: http://localhost:{port}/mcp", style="dim")
+    console.print(f"   Server file: {server_file}", style="dim")
+    console.print(f"   Python interpreter: {venv_python}", style="dim")
     console.print("   Restart Claude Desktop for changes to take effect.", style="yellow")
 
 

libs/arcade-cli/arcade_cli/new.py

@@ -19,14 +19,14 @@ try:
     ARCADE_MCP_MAX_VERSION = str(int(ARCADE_MCP_MIN_VERSION.split(".")[0]) + 1) + ".0.0"
 except Exception as e:
     console.print(f"[red]Failed to get arcade-mcp version: {e}[/red]")
-    ARCADE_MCP_MIN_VERSION = "1.0.0"  # Default version if unable to fetch
+    ARCADE_MCP_MIN_VERSION = "1.1.0"  # Default version if unable to fetch
     ARCADE_MCP_MAX_VERSION = "2.0.0"
 
 ARCADE_TDK_MIN_VERSION = "3.0.0"
 ARCADE_TDK_MAX_VERSION = "4.0.0"
 ARCADE_SERVE_MIN_VERSION = "3.0.0"
 ARCADE_SERVE_MAX_VERSION = "4.0.0"
-ARCADE_MCP_SERVER_MIN_VERSION = "1.0.1"
+ARCADE_MCP_SERVER_MIN_VERSION = "1.1.1"
 ARCADE_MCP_SERVER_MAX_VERSION = "2.0.0"
 
 

libs/arcade-cli/arcade_cli/templates/minimal/{{ toolkit_name }}/pyproject.toml

@@ -9,6 +9,7 @@ description = "MCP Server created with Arcade.dev"
 requires-python = ">=3.10"
 dependencies = [
     "arcade-mcp-server>={{ arcade_mcp_server_min_version }},<{{ arcade_mcp_server_max_version }}",
+    "httpx>=0.28.0,<1.0.0",
 ]
 
 [project.optional-dependencies]

libs/arcade-mcp-server/arcade_mcp_server/__main__.py

@@ -54,7 +54,7 @@ def setup_logging(level: str = "INFO", stdio_mode: bool = False) -> None:
     # Remove existing handlers
     logger.remove()
 
-    # Configure output destination
+    # In stdio mode, use stderr (stdout is reserved for JSON-RPC)
     sink = sys.stderr if stdio_mode else sys.stdout
 
     # Add handler with appropriate format
@@ -69,7 +69,7 @@ def setup_logging(level: str = "INFO", stdio_mode: bool = False) -> None:
         sink,
         format=format_str,
         level=level,
-        colorize=True,
+        colorize=(not stdio_mode),
         diagnose=(level == "DEBUG"),
     )
 

libs/arcade-mcp-server/arcade_mcp_server/mcp_app.py

@@ -103,7 +103,8 @@ class MCPApp:
         self.server: MCPServer | None = None
 
         self._load_env()
-        self._setup_logging()
+        if not logger._core.handlers:  # type: ignore[attr-defined]
+            self._setup_logging(transport == "stdio")
 
     # Properties (exposed below initializer)
     @property
@@ -128,17 +129,21 @@ class MCPApp:
             load_dotenv(env_path, override=False)
             logger.info(f"Loaded environment from {env_path}")
 
-    def _setup_logging(self) -> None:
+    def _setup_logging(self, stdio_mode: bool = False) -> None:
         logger.remove()
+
+        # In stdio mode, use stderr (stdout is reserved for JSON-RPC)
+        sink = sys.stderr if stdio_mode else sys.stdout
+
         if self.log_level == "DEBUG":
             format_str = "<level>{level: <8}</level> | <green>{time:HH:mm:ss}</green> | <cyan>{name}:{line}</cyan> | <level>{message}</level>"
         else:
             format_str = "<level>{level: <8}</level> | <green>{time:HH:mm:ss}</green> | <level>{message}</level>"
         logger.add(
-            sys.stdout,
+            sink,
             format=format_str,
             level=self.log_level,
-            colorize=True,
+            colorize=(not stdio_mode),
             diagnose=(self.log_level == "DEBUG"),
         )
 
@@ -209,10 +214,13 @@ class MCPApp:
             logger.error("No tools added to the server. Use @app.tool decorator or app.add_tool().")
             sys.exit(1)
 
-        logger.info(f"Starting {self.name} v{self.version} with {len(self._catalog)} tools")
-
         host, port, transport = MCPApp._get_configuration_overrides(host, port, transport)
 
+        # Since the transport could have changed since __init__, we need to setup logging again
+        self._setup_logging(transport == "stdio")
+
+        logger.info(f"Starting {self.name} v{self.version} with {len(self._catalog)} tools")
+
         if transport in ["http", "streamable-http", "streamable"]:
             run_arcade_mcp(
                 catalog=self._catalog,

libs/arcade-mcp-server/pyproject.toml

@@ -4,7 +4,7 @@ build-backend = "hatchling.build"
 
 [project]
 name = "arcade-mcp-server"
-version = "1.1.0"
+version = "1.1.1"
 description = "Model Context Protocol (MCP) server framework for Arcade.dev"
 readme = "README.md"
 authors = [{ name = "Arcade.dev" }]

pyproject.toml

@@ -1,6 +1,6 @@
 [project]
 name = "arcade-mcp"
-version = "1.0.2"
+version = "1.1.0"
 description = "Arcade.dev - Tool Calling platform for Agents"
 readme = "README.md"
 license = {file = "LICENSE"}
@@ -21,7 +21,7 @@ requires-python = ">=3.10"
 
 dependencies = [
     # CLI dependencies
-    "arcade-mcp-server>=1.1.0,<2.0.0",
+    "arcade-mcp-server>=1.1.1,<2.0.0",
     "arcade-core>=3.0.0,<4.0.0",
     "typer==0.10.0",
     "rich==13.9.4",
@@ -42,7 +42,7 @@ all = [
     "pytz>=2024.1",
     "python-dateutil>=2.8.2",
     # mcp
-    "arcade-mcp-server>=1.1.0,<2.0.0",
+    "arcade-mcp-server>=1.1.1,<2.0.0",
     # serve
     "arcade-serve>=3.0.0,<4.0.0",
     # tdk