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

Annotations already declare readOnlyHint, idempotentHint, openWorldHint=false and destructiveHint=false, so the safety profile is covered; the description's 'Read-only, no sign-in' largely restates it but adds the useful auth detail of no sign-in required. It also discloses the return payload contents, which the annotations do not.

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 tightly packed sentences with the trigger condition front-loaded, followed by the return shape and the filter behavior. No filler or restatement 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?

For a zero-required-parameter, single-filter list tool with full annotation coverage and no output schema, the description supplies everything needed: when to call it, what it returns, and how the optional parameter changes scope.

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 coverage is 100%, so the baseline is 3, but the description adds genuine value beyond the schema's 'Country name to filter by' by stating that passing country restricts output to one country — clarifying the unfiltered default. It doesn't add format nuances (e.g., exact-match vs partial name), keeping it from a 5.

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 ('which destinations OKstays covers', 'Returns every destination we score') plus the returned fields (country, slug, hotel count), so the agent knows exactly what comes back. It does not explicitly contrast itself with the nearest sibling, get_city_overview, which prevents a 5.

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?

Gives clear triggering conditions: 'when the user asks which destinations OKstays covers' and 'before planning a trip through a country', which implicitly routes the agent here ahead of plan_trip. It also explains the filter/no-filter choice, but names no explicit exclusion or alternative tool for detail-level city data.

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