Search the Zero tool registry. Tools are named, typed operations grouped into toolboxes (entityOps, scene, appearance, lighting, …). With no arguments, returns the toolbox overview — one row per toolbox with its purpose and tool count. `toolbox` returns all of that toolbox's tools; `query` on its own searches every tool and toolbox this world can reach — its own, the builtin library, installed libraries and imports — by meaning (`mode: "semantic"`) or by words (`mode: "keyword"`), and answers the top 25 compact rows: the callable identity, whether the hit is a tool or a toolbox (drill into a toolbox with `toolbox`), and a one-line purpose. The answer names the mode and slot that ran, the worlds it covered, and its status. A `query` given with a `toolbox` searches inside that toolbox's registered tools instead. Pass `schema: true` on a `toolbox` drill-in for full signatures, args, and examples inline, or call describe_tool for one tool's full schema. Run a result with tool_exec. Answered by the attached engine, so it needs one: world.open attaches one. `guides` answers without an engine.