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

Annotations already declare readOnly, idempotent, non-destructive, closed-world behavior, so the safety profile is covered. The description adds two useful behavioral facts beyond that: fuzzy tolerance for misspellings and acceptance of names in any language, plus the explicit note that no prices are returned. It omits failure behavior when the query matches nothing and any hint about multiple matches.

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 sentences, tightly written, with the resource definition front-loaded and the return contract second. The parenthetical example list is long but earns its place by clarifying fuzzy matching. Slightly dense with nested parentheses but no wasted sentences.

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?

An output schema exists, so the description needn't detail return values, and it correctly limits itself to the one contract that matters: slugs to feed other tools, no prices. For a two-parameter read-only lookup with full schema coverage this is largely complete; missing only what happens on no-match or ambiguous matches.

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 both parameters are already documented, and the description largely restates them (names in any language, ISO codes, misspellings, plus the locale-driven name/link language). It adds the 'cities and islands work too' nuance not obvious from the schema's 'Country, territory or region' wording, but nothing about query length limits or the default locale handling beyond what the schema states.

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+resource (find a destination) and enumerates exactly what counts as a destination: country, region like 'Europe'/'Asia', multi-country plan, plus cities and islands. It also scopes the return value ('destination slugs for the other tools; no prices'), which distinguishes it from search_plans and the checkout tools.

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 makes clear this is the lookup step that feeds 'the other tools' by producing slugs, which implies when to use it before plan_trip or search_plans. It does not name a sibling as an alternative or state exclusions (e.g. what to do when the destination isn't found), so it falls short of explicit when/when-not routing.

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