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

Annotations already declare readOnly, idempotent, non-destructive, and closed-world, so safety needs no restating. The description adds useful output composition (service-area providers, sub-region providers, headquarters providers, worldwide count), but says nothing about ordering, pagination, or how the optional country filter changes scope.

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 the output breakdown front-loaded and the use case trailing. Dense but every clause carries information; only the semicolon-heavy listing slightly slows parsing.

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?

With an output schema, rich annotations, and one optional parameter, the definition is nearly sufficient: the agent knows what the returned coverage categories mean and the safety profile. The remaining gap is scoping behavior when the country parameter is omitted versus supplied.

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% and the single optional parameter is documented there as "just this country." The description only implies the default all-countries behavior via "For each country," adding marginal meaning beyond the schema, so baseline 3 applies.

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 states precisely what the tool returns: per-country breakdowns of three provider categories plus a worldwide count. That's a clear resource and output shape, though it never explicitly contrasts with siblings like find_providers or compare_providers, so an agent must infer the difference.

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?

"Use to tell the buyer honestly how well their country is covered" gives a use case, so usage is implied rather than left blank. But no alternative is named and no when-not-to-use condition is stated, so routing between this and find_providers is left to inference.

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