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

Annotations already declare readOnlyHint, idempotentHint, non-destructive and closed-world, so the safety profile is covered. The description adds value beyond that by disclosing the shape of the payload (counts, main pages, sister sites), which matters since there is no output schema. It stops short of format/volume details.

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?

One sentence, front-loaded with the resource identity, then a terse action directive ("Call it first"). No filler and every clause contributes return-value 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?

With no parameters, no output schema and full annotation coverage, the description's main job is to describe what comes back, which it does thoroughly. Minor gaps remain (structure of "main pages" and "sister sites", any caching/pagination), but these are low-stakes for a zero-arg metadata 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?

The tool takes no parameters, so the baseline is 4. Nothing in the description needs to compensate for a schema gap, and there are no parameter semantics to clarify.

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 enumerates precisely what the tool returns about the site itself (name, country, language, currency, shop and live-offer counts, main pages, sister sites), which is a clearly distinct resource from every sibling (get_shop, list_categories, list_coupons, list_events, search_shops), all of which deal with shops/coupons rather than site metadata.

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?

"Call it first" is an explicit, unambiguous usage directive that tells the agent when to reach for this tool. It does not name alternatives or state exclusions, but the sequencing guidance is concrete rather than implied.

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