> I never really understood why you have to stuff all the tools in the context.

You probably don't for... like, trivial cases?

...but, tool use is the most fine grained point, usually, in an agent's step-by-step implementation plan; So when planning, if you don't know what tool definitions exist, an agent might end up solving a problem naively step-by-step using primitive operations, when a single tool already exists that does that, or does part of it.

Like, it's not quite as simple as "Hey, do X"

It's more like: "Hey, make a plan to do X. When you're planning, first fetch a big list of the tools that seem vaguely related to the task and make a step-by-step plan keeping in mind the tools available to you"

...and then, for each step in the plan, you can do a tool search to find the best tool for x, then invoke it.

Without a top level context of the tools, or tool categories, I think you'll end up in some dead-ends with agents trying to use very low level tools to do high level tasks and just spinning.

The higher level your tool definitions are, the worse the problem is.

I've found this is the case even now with MCP, where sometimes you have to explicitly tell an agent to use particular tools, not to try to re-invent stuff or use bash commands.