Merge pull request #19 from jlowin/cli

Update cli file spec

examples/desktop.py

@@ -23,7 +23,3 @@ def desktop() -> list[str]:
 def add(a: int, b: int) -> int:
     """Add two numbers"""
     return a + b
-
-
-if __name__ == "__main__":
-    mcp.run()

examples/echo.py

@@ -15,16 +15,17 @@ def echo_tool(text: str) -> str:
     return text
 
 
+@mcp.resource("echo://static")
+def echo_resource() -> str:
+    return "Echo!"
+
+
 @mcp.resource("echo://{text}")
-def echo_resource(text: str) -> str:
+def echo_template(text: str) -> str:
     """Echo the input text"""
     return f"Echo: {text}"
 
 
 @mcp.prompt("echo")
 def echo_prompt(text: str) -> str:
     return text
-
-
-if __name__ == "__main__":
-    mcp.run()

examples/screenshot.py

@@ -26,7 +26,3 @@ def take_screenshot() -> Image:
     # if the file exceeds ~1MB, it will be rejected by Claude
     screenshot.convert("RGB").save(buffer, format="JPEG", quality=60, optimize=True)
     return Image(data=buffer.getvalue(), format="jpeg")
-
-
-if __name__ == "__main__":
-    mcp.run()

examples/simple_echo.py

@@ -13,7 +13,3 @@
 def echo(text: str) -> str:
     """Echo the input text"""
     return text
-
-
-if __name__ == "__main__":
-    mcp.run()

src/fastmcp/cli/claude.py

@@ -25,8 +25,8 @@ def get_claude_config_path() -> Path | None:
 
 
 def update_claude_config(
-    file: Path,
-    server_name: Optional[str] = None,
+    file_spec: str,
+    server_name: str,
     *,
     with_editable: Optional[Path] = None,
     with_packages: Optional[list[str]] = None,
@@ -35,9 +35,8 @@ def update_claude_config(
     """Add the MCP server to Claude's configuration.
 
     Args:
-        file: Path to the server file
-        server_name: Optional custom name for the server. If not provided,
-                    defaults to the file stem
+        file_spec: Path to the server file, optionally with :object suffix
+        server_name: Name for the server in Claude's config
         with_editable: Optional directory to install in editable mode
         with_packages: Optional list of additional packages to install
         force: If True, replace existing server with same name
@@ -55,46 +54,49 @@ def update_claude_config(
         if "mcpServers" not in config:
             config["mcpServers"] = {}
 
-        # Use provided server_name or fall back to file stem
-        name = server_name or file.stem
-        if name in config["mcpServers"]:
+        if server_name in config["mcpServers"]:
             if not force:
                 logger.warning(
-                    f"Server '{name}' already exists in Claude config. "
+                    f"Server '{server_name}' already exists in Claude config. "
                     "Use `--force` to replace.",
                     extra={"config_file": str(config_file)},
                 )
                 return False
             logger.info(
-                f"Replacing existing server '{name}' in Claude config",
+                f"Replacing existing server '{server_name}' in Claude config",
                 extra={"config_file": str(config_file)},
             )
 
         # Build uv run command
-        args = ["run"]
+        args = ["run", "--with", "fastmcp"]
 
         if with_editable:
             args.extend(["--with-editable", str(with_editable)])
 
-        # Always include fastmcp
-        args.extend(["--with", "fastmcp"])
-
-        # Add additional packages
         if with_packages:
             for pkg in with_packages:
                 if pkg:
                     args.extend(["--with", pkg])
 
-        args.append(str(file))
+        # Convert file path to absolute before adding to command
+        # Split off any :object suffix first
+        if ":" in file_spec:
+            file_path, server_object = file_spec.rsplit(":", 1)
+            file_spec = f"{Path(file_path).resolve()}:{server_object}"
+        else:
+            file_spec = str(Path(file_spec).resolve())
+
+        # Add fastmcp run command
+        args.extend(["fastmcp", "run", file_spec])
 
-        config["mcpServers"][name] = {
+        config["mcpServers"][server_name] = {
             "command": "uv",
             "args": args,
         }
 
         config_file.write_text(json.dumps(config, indent=2))
         logger.info(
-            f"Added server '{name}' to Claude config",
+            f"Added server '{server_name}' to Claude config",
             extra={"config_file": str(config_file)},
         )
         return True

src/fastmcp/cli/cli.py

@@ -24,11 +24,11 @@
 
 
 def _build_uv_command(
-    file: Path,
+    file_spec: str,
     with_editable: Optional[Path] = None,
     with_packages: Optional[list[str]] = None,
 ) -> list[str]:
-    """Build the uv run command."""
+    """Build the uv run command that runs a FastMCP server through fastmcp run."""
     cmd = ["uv"]
 
     cmd.extend(["run", "--with", "fastmcp"])
@@ -41,7 +41,8 @@ def _build_uv_command(
             if pkg:
                 cmd.extend(["--with", pkg])
 
-    cmd.append(str(file))
+    # Add fastmcp run command
+    cmd.extend(["fastmcp", "run", file_spec])
     return cmd
 
 
@@ -89,15 +90,17 @@ def _import_server(file: Path, server_object: Optional[str] = None):
     module = importlib.util.module_from_spec(spec)
     spec.loader.exec_module(module)
 
-    # If no object specified, try __main__ block
+    # If no object specified, try common server names
     if not server_object:
         # Look for the most common server object names
         for name in ["mcp", "server", "app"]:
             if hasattr(module, name):
                 return getattr(module, name)
 
         logger.error(
-            f"No server object found in {file}. Please specify the object name with file:object syntax.",
+            f"No server object found in {file}. Please either:\n"
+            "1. Use a standard variable name (mcp, server, or app)\n"
+            "2. Specify the object name with file:object syntax",
             extra={"file": str(file)},
         )
         sys.exit(1)
@@ -178,7 +181,7 @@ def dev(
     )
 
     try:
-        uv_cmd = _build_uv_command(file, with_editable, with_packages)
+        uv_cmd = _build_uv_command(file_spec, with_editable, with_packages)
         # Run the MCP Inspector command
         process = subprocess.run(
             ["npx", "@modelcontextprotocol/inspector"] + uv_cmd,
@@ -229,7 +232,12 @@ def run(
         ),
     ] = None,
 ) -> None:
-    """Run a FastMCP server."""
+    """Run a FastMCP server.
+
+    The server can be specified in two ways:
+    1. Module approach: server.py - runs the module directly, expecting a server.run() call
+    2. Import approach: server.py:app - imports and runs the specified server object
+    """
     file, server_object = _parse_file_path(file_spec)
 
     logger.debug(
@@ -338,7 +346,7 @@ def install(
             name = file.stem
 
     if claude.update_claude_config(
-        file,
+        file_spec,
         name,
         with_editable=with_editable,
         with_packages=with_packages,
@@ -348,7 +356,3 @@ def install(
     else:
         print(f"Failed to install {name} in Claude app")
         sys.exit(1)
-
-
-if __name__ == "__main__":
-    app()