MCP vs Function Calling vs LangChain: Which Wins in 2026?
Three approaches dominate how AI agents call external tools in 2026: the Model Context Protocol (MCP), OpenAI Function Calling, and LangChain Tools. MCP is an open protocol for runtime tool discovery across any AI provider. OpenAI Function Calling is a proprietary API feature tightly integrated with OpenAI models. LangChain Tools is a framework abstraction that wraps tool definitions for orchestration pipelines. They solve different problems, operate at different layers, and can coexist in the same architecture.
