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

With no annotations, the description carries the full burden. It usefully discloses output formats and country-code coverage, including the UK coordinates-only exception. But it does not state read-only nature, permission requirements, or error behavior; for a read tool this is adequate but not rich.

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 dense sentences with no waste. The purpose and outputs come first, followed by input compatibility constraints, making it well front-loaded and easy to scan.

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?

The tool is simple, has full schema coverage, and no output schema. The description appropriately explains return values (GeoJSON, ring, centroid, area) and input coverage. Minor gaps like coordinate reference system or precision are not critical for selection.

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. The description adds meaning by clarifying that references use the same 30 codes as get_parcel and that the UK is coordinates-only, which goes beyond the schema's generic 'Official cadastral reference' and country auto-detect notes.

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 description gives a specific verb (get) and resource (parcel boundaries) and states the exact outputs: outline as GeoJSON and/or [lat, lng] ring, plus centroid and area. It clearly distinguishes the tool from get_parcel by focusing on geometry rather than parcel attributes.

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?

It provides clear context for use ('for mapping and GIS work') and specifies input compatibility with get_parcel references, including the UK exception. However, it stops short of explicitly saying when to choose this tool over alternatives like get_parcel or compare_parcels.

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