Shelf four · Agents, tools & reinforcement
Tools & MCP
Kitchen table
On its own, the machine can only talk. Tools give it hands: now it can actually look up today's weather, do the sum on a real calculator, or send the permission slip, instead of just describing how one might. Each tool is like a button it is allowed to press, with a label explaining what the button does. Choose the buttons carefully. You would not give the class hamster the fire-alarm button, however clever the hamster.
Whiteboard
Function calling with schemas, and MCP emerging as the standard for exposing tools across vendors – write once, plug into any model. What actually decides whether the model uses a tool correctly is craft, not protocol: names that say what they do, descriptions written for a reader with no context, arguments that resist misuse, error messages that teach, idempotency so a retry is safe. A tool's interface is a prompt. Design it with the same care.
Boardroom
This is the integration layer – how AI reaches your actual systems: the CRM, the ledger, the scheduler. Standardisation here is good news commercially (less bespoke plumbing, less lock-in) but the strategic point is sharper: every tool is a capability grant, and the tool boundary is exactly where access control must live. The model will improvise. The tools must not let improvisation become damage. Review an agent's tool list the way you review a new hire's system access, because that is what it is.
Related concepts