feat(mcp): allow MCP Server --tool_name filter to reference function groups (#1093)

`nat mcp serve --tool_names` only filtered based on function names.
This should be expanded to support function group names as well.




Closes

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## Summary by CodeRabbit

* **New Features**
  * Enhanced function registration now supports group prefix-based filtering alongside exact name matching, providing more flexible organization and selection of available functions.

Authors:
  - Will Killian (https://github.com/willkill07)

Approvers:
  - Eric Evans II (https://github.com/ericevans-nv)

URL: #1093

Author: willkill07

src/nat/front_ends/mcp/mcp_front_end_config.py

@@ -37,8 +37,11 @@ class MCPFrontEndConfig(FrontEndBaseConfig, name="mcp"):
     port: int = Field(default=9901, description="Port to bind the server to (default: 9901)", ge=0, le=65535)
     debug: bool = Field(default=False, description="Enable debug mode (default: False)")
     log_level: str = Field(default="INFO", description="Log level for the MCP server (default: INFO)")
-    tool_names: list[str] = Field(default_factory=list,
-                                  description="The list of tools MCP server will expose (default: all tools)")
+    tool_names: list[str] = Field(
+        default_factory=list,
+        description="The list of tools MCP server will expose (default: all tools)."
+        "Tool names can be functions or function groups",
+    )
     transport: Literal["sse", "streamable-http"] = Field(
         default="streamable-http",
         description="Transport type for the MCP server (default: streamable-http, backwards compatible with sse)")

src/nat/front_ends/mcp/mcp_front_end_plugin_worker.py

@@ -234,6 +234,10 @@ async def add_routes(self, mcp: FastMCP, builder: WorkflowBuilder):
             filtered_functions: dict[str, Function] = {}
             for function_name, function in functions.items():
                 if function_name in self.front_end_config.tool_names:
+                    # Treat current tool_names as function names, so check if the function name is in the list
+                    filtered_functions[function_name] = function
+                elif any(function_name.startswith(f"{group_name}.") for group_name in self.front_end_config.tool_names):
+                    # Treat tool_names as function group names, so check if the function name starts with the group name
                     filtered_functions[function_name] = function
                 else:
                     logger.debug("Skipping function %s as it's not in tool_names", function_name)