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

Annotations already declare readOnlyHint, idempotentHint, and destructiveHint, so the safety profile is known. The description adds useful context: it is account-scoped, summary-level, and enumerates the metrics included. No contradictions or hidden behaviors are apparent.

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?

A single well-structured sentence packs the resource, metrics, use case, and positioning relative to next-step suggestions. Every clause adds value, with no repetition of schema or annotation information.

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 zero-parameter, read-only summary tool, the description fully covers invocation context. It names the returned metric categories and the primary use case, so an agent can decide to call it without needing an output schema.

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?

The tool has zero parameters, making the schema trivially complete at 100% coverage. Per the 0-param baseline, the description is not required to explain parameters, and it doesn't need to; there is nothing to document.

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 returns a summary of the account's map: countries, territories, regions, places, Explorer score, and world explored. This distinguishes it from siblings like get_badges, get_rank, and list_visited, which serve different reporting purposes.

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 explicitly tells the agent when to use this tool: to answer 'how many countries have I been to' and as the quickest way to assess user standing before suggesting additions. It does not explicitly name excluded alternatives, but the use-case framing is clear enough.

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