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

Annotations already declare read-only, idempotent, non-destructive, closed-world behavior, and the description goes well beyond that: US-only open-data coverage, owner names and values explicitly excluded, boundary lines approximate and not a survey-grade, and data-retention implications on paid plans. These are exactly the operational caveats an agent cannot infer from structured fields.

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 purpose and return payload are front-loaded in one dense sentence, which is good. The trailing 'Growth plans and up; counts 1 address lookup' and the storage-retention sentence are billing/plan boilerplate that dilutes the operational content and slightly muddies what the agent should act on.

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?

With no output schema, the description carries the return-value burden and does so by naming the returned fields and their units. Coverage limits and disclaimers are present; what is missing is behavior on no-match or ambiguous points and any hint of response shape, which matters for a geospatial lookup.

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%, including lat/lon pairing rules, the geometry enum values, and the parcel_id example format, so the schema already does the heavy lifting. The description only restates the two mutually exclusive input modes and adds no syntax or constraint detail beyond the schema, making 3 the appropriate baseline.

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?

Opens with a specific verb and resource ('Get the property parcel (lot)') and enumerates exactly what comes back: boundary, APN, area in m²/acres, source and date. It also names the two lookup modes (lat/lon or parcel_id). It never contrasts itself with siblings such as reverse_geocode or district_lookup, so it falls short of a 5.

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?

Usage is only implied through input-mode phrasing ('at a latitude/longitude, or by parcel_id'). Coverage constraints ('US coverage from open government data only', county list pointer) act as a de facto when-not, but there is no explicit guidance on choosing this over reverse_geocode or district_lookup for the same coordinates.

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