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

With readOnlyHint true, the description adds valuable context beyond the annotation: it lists return contents (metadata, vintage, centroid, bounding box, optional polygon) and mentions 'No payment required.' It also discloses a limitation (does not explain hierarchy). These are useful behavioral insights without contradicting the annotation.

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 two focused sentences, front-loaded with the core purpose ('Shape retrieval for exact loc_ids'). Every clause earns its place: scope, return values, alternative tool, usage preference, and payment note. No redundancy.

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 tool with complete schema descriptions and readOnlyHint annotation, the description covers the essential aspects: what it retrieves, what it returns (including optional polygon), its limitations, and when to use alternatives. No output schema exists, but the description sufficiently outlines return components. It is contextually complete.

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 minimal parameter-specific semantics beyond the schema: it references 'optional GeoJSON polygon' (tied to include_polygon) and advises preferring bbox/centroid, but does not elaborate on batch behavior or format. This is sufficient but not additive beyond 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?

The description clearly states the tool retrieves geometry ('Shape retrieval') for specific loc_ids, and explicitly distinguishes it from loc_id_info by noting it does not explain hierarchy or crosswalks. It also specifies the scope (exact loc_ids and resolve_point chain levels), making its purpose unambiguous.

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?

Explicitly provides when to use alternatives: 'It does not explain hierarchy or crosswalks; use loc_id_info for those details.' Also gives a clear preference rule: 'Prefer bbox/centroid unless exact rendering or clipping requires the polygon.' This is strong usage guidance.

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