The ANTLR4 MCP Server is designed to enable AI assistants, such as Claude and Cursor, to directly interact with ANTLR4 grammars. It provides a comprehensive set of tools for grammar development, offering instant validation, parsing, and deep analysis capabilities via natural language. Users can paste grammars into conversations to receive quick feedback on syntax, detect ambiguities, generate parse trees, and even compile grammars for various target languages, significantly streamlining the grammar creation and debugging process.