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

Annotations already declare readOnlyHint=true and destructiveHint=false, so the description doesn't need to restate safety. It adds valuable context beyond annotations: 'no auth required' (auth requirement is not covered by annotations) and data provenance ('Data: geoBoundaries (William & Mary geoLab)'). It also lists output fields, giving behavioral insight into the return structure. No contradiction with annotations.

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 sentences with zero fluff. The core action and scope are front-loaded ('List every country's administrative boundary metadata at one level'), followed by the field list and the use-case hook. Every sentence earns its place.

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?

Given the output schema exists, the description doesn't need to explain return format. It mentions the key fields returned, the data source, auth requirement, and the intended use case. It doesn't discuss pagination or limits, but for a country list that's likely minor. Overall, complete enough for an agent to call 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 description coverage is 100% for the single adm_level parameter, with a detailed enum description and default noted. The description adds no parameter-specific information beyond what the schema already provides. Per guidelines, baseline 3 is appropriate when schema carries the full load.

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's action ('List every country's administrative boundary metadata at one level'), the resource (geoBoundaries), and the specific fields returned (ISO3, name, admin unit count, continent/region, geometry URLs). It explicitly differentiates from the sibling tool geoboundaries.boundary.detail by noting it is for discovering coverage before requesting a single country, making it 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?

The description provides explicit context: 'Useful for discovering coverage before requesting a single country with geoboundaries.boundary.detail.' This tells the agent when to use this tool (for coverage discovery) and implies not to use it for single-country details. However, it doesn't mention other alternatives like geoboundaries.boundary.available_levels or when not to use it, so it's slightly incomplete but clear.

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