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

Annotations already declare readOnly, idempotent, closed-world and non-destructive, so the safety profile is covered. The description adds one genuinely useful behavioral fact — that counts are of *visible* properties only — but says nothing about freshness or how the counts are scoped (per atoll vs. global).

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 front-loaded sentence that carries the resource, the scope qualifier, and the two metrics with zero filler. Nothing could be removed without losing meaning.

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 parameterless aggregate, the description effectively names the return values, and annotations handle the safety profile; no output schema is needed. The only omission is whether the counts are global to the catalog or filterable, but with zero parameters global is the safe reading.

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 takes zero parameters, so there is nothing to disambiguate and no schema semantics to compensate for. Baseline 4 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?

States a concrete resource (catalog coverage) and the exact metrics returned: visible property count and atoll count. It is distinguishable from the sibling list_* tools, which enumerate entities rather than summarize totals, though it doesn't name an alternative explicitly.

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?

Usage is only implied: an agent can infer this is for gauging dataset completeness before/after searching. There is no explicit when-to-use, no exclusion, and no pointer to list_atolls or search_resorts as the detailed counterparts.

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