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

No annotations are provided, so the description carries the full burden. It states the tool is 'computed live' and lists return values, implying a read-only operation. It does not disclose rate limits or performance characteristics, but the information given is sufficient for typical use.

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 sentences long, front-loading the key idea ('Headline statistics computed live'), and every word adds value. No redundancy or verbosity.

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?

Despite lacking an output schema, the description comprehensively lists the types of statistics returned (totals, top countries, fame tiers, etc.) and gives example questions. This is complete for a no-parameter, read-only tool.

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?

With zero parameters and 100% schema coverage (by default), the baseline is 4. The description adds no parameter info because there are none, but that is appropriate.

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 is specific and informative: it states the tool computes 'headline statistics' from the atlas, listing categories like totals by kind, top countries, etc. It provides examples of questions it answers, clearly distinguishing it from siblings that handle individual places, lists, or spatial queries.

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 implies usage for aggregate claims ('how many castles') but does not explicitly state when to use this tool over siblings or when not to use it. No direct comparison or exclusion criteria are provided, leaving the agent to infer context.

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