MCP in agentic AI wins against plain function calling for any team whose agents need to outlive a single model, framework or application. Function calling is a contract you re-implement inside every app you ship; the Model Context Protocol is a standard protocol layer, so one server integration works across the clients that already speak it, including Claude, Cursor, VS Code, Microsoft Copilot, Gemini and ChatGPT ( Linux Foundation ). The exception is narrow and real: if you are one developer co...