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

Annotations already declare readOnlyHint=true, idempotentHint=true, and openWorldHint=false, so the safety profile is fully covered. The description adds useful behavioral content by disclosing what data comes back (countries plus their venue counts), but says nothing about ordering, completeness, or whether the set is cached. Adequate but not rich.

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 sentence, front-loaded with the verb and resource and ending with the distinguishing detail (counts per country). No filler, no repetition of the title.

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 carries nearly all the burden and does so competently by stating the result shape. Minor gap: it does not say whether results are exhaustive or how they are ordered, but for a simple listing endpoint nothing essential is missing.

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 the baseline of 4 applies. There is nothing for the description to clarify beyond the scope of the result set, which it already does by naming 'published' venues.

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 specific verb (Lists) and resource (countries), plus the exact scope: countries with published wedding venues on Aisle and per-country venue counts. This is far more precise than a sibling like list_vendor_categories would imply. It doesn't explicitly contrast itself with search_venues, but the purpose is unambiguous on its own.

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 its role as a browse/facet lookup, but never says when to use this versus search_venues or get_venue_details, nor any precondition. Usage is inferable from the stated output (country + count), which is the minimum-viable level.

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