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

Annotations already declare readOnlyHint=true, destructiveHint=false, and openWorldHint=true, so the safety profile is covered. The description adds value beyond that: the data source ('live site map, so it is comprehensive and always current') and the two-mode response shape. It does not discuss pagination or rate limits, but for a read-only lookup that is minor.

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?

Front-loaded with the core purpose and scoping behavior, which is the right ordering. It is somewhat long, since the trailing proper-noun and price-preservation rules read as response-formatting policy rather than tool selection guidance, but each sentence does carry usable instruction.

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?

There is no output schema, and the description compensates by describing the shape of results (countries each with a city count, or cities within a country). Combined with the annotations covering safety, an agent has enough to call it correctly; only the exact response envelope is unspecified.

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 description coverage is 100%, and both fields (locale, country) are documented in the schema itself. The description reinforces the country parameter's behavioral meaning (country in → cities out, omit → all countries), but adds no syntax, format, or validation detail beyond the schema. Baseline 3 applies when the schema does the heavy lifting.

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 states a specific verb and resource — 'List all destinations where DayPass is live' — and defines the two resolution modes (all countries with city counts, or cities within a given country). This is clearly distinguishable from siblings like search_experiences or check_availability.

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?

It gives an explicit trigger condition: 'Use when the user has not named a place, or names a large country and you need to ask which city.' That is strong context. It stops short of naming an alternative tool for the case where the user has named a specific place, so routing is implied rather than fully specified.

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