The MCP Dynamic Tool Groups project demonstrates how to create and manage ToolGroups on an MCP server at runtime using annotated Java interfaces/classes. It uses McpTool and McpToolParam annotations to embed tool metadata directly in the interface (example ToolGroup: add, multiply, asyncAdd, asyncMultiply). The ExampleToolGroup interface is registered on the server via the ToolGroupComponent OSGi component, which injects SyncMcpToolGroupServer and AsyncMcpToolGroupServer and registers the group with addToolGroups during activation. Tools can be listed, invoked with input, and output retrieved; the server supports both synchronous and asynchronous operations. Tool specs are generated on activation and collected in syncSpecifications and asyncSpecifications; on deactivate, they are removed from the server via removeTools. The approach relies on reflection to derive tool definitions from the interface, ensuring metadata is part of the API contract. The README notes that this approach can be duplicated in other languages and that Nested ToolGroups can be created or added via other data sources or tooling, enabling flexible organization and testing, including red-teaming use cases.