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

Annotations already declare readOnlyHint=true and destructiveHint=false, and the description goes well beyond them: it discloses corpus coverage limits (national but not complete, not live), how to read an empty result, that a corpus_coverage block is returned, and that the call is free of token cost.

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?

Front-loaded with the core behaviour and the sibling routing in the first two sentences. The coverage paragraph is long but each sentence carries non-obvious operational guidance; only the trailing 'Free' note is slightly expendable.

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?

No output schema exists, so the description correctly takes on the burden of describing what comes back (district, area, GPS coordinates, corpus_coverage block). Combined with the coverage caveat and the fallback to resolve_parcel, an agent has everything needed to call and interpret it 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 the baseline is 3, but the description adds real meaning the schema does not: the match is on the ID PREFIX only, never on an area, plus a concrete example prefix. The limit parameter is left entirely to the schema.

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 (search) and resource (land parcels) and immediately constrains the match semantics to ID prefix. It names the two sibling tools it is not (list_parcels_in_area, resolve_parcel), letting an agent distinguish it without opening any schema.

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?

Explicit when-to-use ('finding exact parcel IDs', 'searching transactions nearby') and when-not, with a named alternative for each wrong case: list_parcels_in_area for places/shapes and resolve_parcel for address/coordinate/locality lookups. Also covers how to interpret an empty result.

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