What Is Tool Calling Function Calling 2026
Tool calling Anthropic's term — or function calling OpenAI's term — is the LLM ability to invoke predefined functions instead of just generating text. The Idea Without tool calling, an LLM only outputs text. With tool calling: 1. You define tools with schemas 2. LLM decides to invoke one 3. LLM outputs a JSON toolcall 4. Your code runs the function 5. You feed the result back to the LLM 6. LLM co…