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

Annotations already declare readOnly, idempotent, non-destructive and closed-world, so the safety profile is covered. The description adds genuinely new behavioral context beyond that: only countries with *published* venues are included, and venues lacking a price band are counted separately rather than dropped. It omits pagination/ordering and what the price bands actually are, so not a 5.

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 with no filler; the scope constraint and the three counting dimensions all earn their place. It is somewhat dense and comma-heavy, which slightly hurts parseability, but nothing is wasted.

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 output schema and no parameters, the description carries the return-value burden and does so well, spelling out every count it returns. Minor gaps remain (no ordering, no definition of the price bands, no indication of result size), but an agent has enough to call it correctly.

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 and the schema is empty, so there is nothing for the description to clarify. Per the baseline for 0-param tools, this is a 4.

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 and resource ('Lists countries with published wedding venues') and goes further to specify the aggregation granularity: counts per country broken down by venue type, by searchable price band, and a no-price-band count. That result shape cleanly distinguishes it from siblings like search_venues or list_vendor_categories, so an agent knows this is a directory/aggregation endpoint, not a lookup.

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?

No explicit when-to-use, when-not-to-use, or named alternative is given. The intent is inferable from the purpose (browse venue distribution by country), which is adequate but leaves the agent to decide on its own whether to call this or search_venues for discovery.

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