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

Annotations already tell the agent this is a safe, read-only, idempotent lookup, but the description adds important operational behavior beyond them: 3 credits per request regardless of result count, no charge for uncovered counties or failed requests, API-key requirement, 5,000 m radius cap, 1,000 parcel cap, nearest-first ordering, and returned fields including WKT EPSG:4326. These details materially affect whether and how to call the tool.

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?

The description is front-loaded with the core purpose and ordering, then groups billing, limits, authentication, and return fields into a compact paragraph. It repeats the radius and parcel caps already present in the schema, which keeps it from a 5, but the repetition is operational rather than verbose.

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 spatial query with no output schema, the description supplies the missing context an agent needs: cost model, coverage-related free lookups, API-key requirement, result caps, ordering, and the shape of returned parcel records. Nothing essential for correct invocation appears absent.

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 the schema already documents lat, lng, radius_m, limit, and offset with ranges and defaults. The description reinforces radius and limit caps and adds ordering and return-format context, but it does not explain parameter semantics beyond the schema, so the baseline of 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?

The first sentence states a specific verb and resource — finds every parcel — plus the spatial scope (within a radius of a point) and ordering (nearest first). This clearly separates it from siblings such as find_parcels_at_point, find_parcels_in_polygon, and find_parcels_by_apn without requiring schema inspection.

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 makes clear the tool is for center-plus-radius searches, but it gives no explicit when-to-use guidance against alternatives like find_parcels_at_point or find_parcels_in_polygon, nor does it advise running check_coverage first. The radius and page-size limits imply suitable use cases but leave routing to the agent.

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