Function calling

The wiring underneath a tool call. The AI can't actually do anything itself. All it can do is write out a precisely formatted request — send an email, to this address, with this subject — and the software around it reads that request and carries it out. The AI asks. The software acts.

Three words for one shelf again: the tool is the drill, the tool call is one hole, and function calling is the wiring that makes the trigger do something when you pull it.

Why it matters: worth knowing precisely because the AI never truly does anything — it only ever requests. Every real safety control lives in that software layer, in the decision about whether to honour the request. So "can your AI send emails on its own?" is really a question about what the software around it has been allowed to say yes to.

Related: Tool / tool call · Guardrail