A tool list is also a security surface

Dynamic tool discovery is usually framed as a way to keep irrelevant schemas out of context. It is also a policy decision. The available tool surface tells the reasoning system which classes of action are currently possible.

That makes tool design simultaneously model UX, security architecture, policy surface, and observability design. A narrow, named operation is easier to authorize, constrain, audit, simulate, rate-limit, and verify than a general shell-shaped escape hatch.

This note records a bounded architectural hypothesis, not a hands-on observation, tested environment, or claim about a released ReactorJet runtime. See Authority Compiler and Giving an agent a shell is not the same as giving it a tool.