Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

The annotations already declare this as a read-only, open-world, idempotent, non-destructive lookup. The description goes beyond them with cost (1 unit), an auth prerequisite (API key or connected account), and the fact that results are ids to feed into get_boundary. That is meaningful operational context, though it doesn't specify rate limits or result ordering guarantees in detail.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Is the description appropriately sized, front-loaded, and free of redundancy?

Four short sentences, front-loaded with what the tool returns and the hierarchy it returns it in. Each sentence adds distinct information: output content, use case, cost, auth, and chaining to get_boundary, with no filler.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

For a two-parameter lookup with no output schema, the description covers what comes back (ids), cost, auth, and the natural next call, which is enough to invoke it correctly. It could say more about the shape of each returned boundary entry, but the essential calling information is present.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Schema coverage is 100% and both lat and lon carry range and unit descriptions, so the input side is fully documented structurally. The description adds nothing beyond implying a single 'point', which is the expected baseline when the schema does all the work.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Does the description clearly state what the tool does and how it differs from similar tools?

The description states a specific operation on a specific resource: every administrative boundary containing a point, ordered country down to smallest district plus postcode areas. That wording distinguishes it from siblings like contains_points and search_boundaries without the agent needing to open their schemas.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Does the description explain when to use this tool, when not to, or what alternatives exist?

It gives a concrete use case (tag an address, store, or delivery with country, state, county, city in one call), which tells the agent the scenario this tool is for. It stops short of explicitly naming when to prefer contains_points or search_boundaries instead, so it is strong context rather than a full routing rule.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.