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

Beyond the annotations (readOnly, idempotent, non-destructive, non-open-world), the description discloses billing (1 credit per request regardless of result count), the 1,000-parcel ceiling, API key requirement, non-charging failure/uncovered-county behavior, and the shape and CRS of the return payload. These are exactly the operational facts annotations cannot carry.

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?

Six short sentences, front-loaded with what the tool does, then cost, then constraints, then return shape. Dense and readable; the only minor waste is restating the 1,000-parcel cap that the limit parameter already enforces.

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 point lookup with four fully described parameters and no output schema, the description covers action, geometry, cost model, auth, coverage caveats, and returned fields. An agent has everything needed to decide and invoke correctly.

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%, so lat/lng/limit/offset semantics are already fully documented in the schema, establishing a baseline of 3. The description adds a modest amount beyond that by tying the 1,000-parcel cap to billing behavior and noting results come back in EPSG:4326, but it does not explain offset paging beyond what the schema says.

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?

"Finds the parcels that contain a latitude and longitude" gives a specific verb (finds), resource (parcels) and geometric scope (containment of a point). That scope cleanly separates it from the siblings find_parcels_in_polygon, find_parcels_in_radius and find_parcels_by_apn without needing to name them.

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 costs-and-coverage sentences imply when the call is cheap or free (uncovered counties, failed requests) and hint that coverage should be verified first, which points at check_coverage/preview_area. But there is no explicit statement of when to choose this over find_parcels_in_radius or find_parcels_in_polygon, so routing is left to inference.

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