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

Annotations already declare readOnlyHint=true, destructiveHint=false, openWorldHint=true, so the safety profile is covered. With no output schema, the description carries the burden of the return shape and does so concretely (in_service_area plus matching/other/closest territories), which is meaningful added context. It omits auth needs, rate limits, and error/geocoding-failure behavior.

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?

Two tight sentences: the return-value behavior is front-loaded and the input options follow immediately, with the GET path appended as a compact reference. Nothing is padded, though the raw endpoint string is marginal for agents that never see the API surface.

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 read-only, four-parameter lookup with full schema coverage but no output schema, the description supplies what the schema cannot: the response fields and the closest-territory fallback when the location is outside all areas. It lacks only failure-mode and authentication context.

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 description coverage is 100%, and the schema already states that lat must be sent with lng and that address is only needed absent a postal code or coordinates. The description's 'postal code, address, or lat + lng' phrasing loosely implies these are alternative input modes, but adds no syntax, format, or precedence detail beyond the schema, so the baseline 3 applies.

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?

States a specific verb+resource ('Check whether a location is inside the business's service area') and enumerates the exact return fields (in_service_area, matching territory, other territories, closest territory when outside). This is clearly distinguishable from siblings like zenbooker_get_territory and zenbooker_list_territories, which retrieve territory data rather than testing a location against coverage.

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?

The description gives the accepted input forms ('Give a postal code, an address, or lat + lng'), which tells the agent how to invoke it, but never states when this tool should be chosen over get_territory/list_territories or any exclusion conditions. Usage is implied rather than explicit.

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