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

Annotations already declare readOnlyHint, idempotentHint, openWorldHint and destructiveHint=false, so the safety profile is covered. The description adds value beyond that: omitted filters fall back to Sorted's defaults rather than being disabled, passport values are normalized against the visa table (aliases like United States accepted), and destination lists must never be invented. It does not discuss result ordering or pagination, but with an output schema present that omission 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?

The purpose is front-loaded in one line, followed by a compact block of imperative rules that are each actionable. It is slightly long and mildly repetitive (both 'Never invent a destination list' and 'Do not use this for live flight tickets' guard against the same failure mode), but every sentence carries operational meaning.

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 25-parameter, zero-required tool with rich annotations and an output schema, the description covers the highest-risk failure modes: accidental filter setting, implicit false values, and passport value formats. The main residual gap is that the dependent flag pairs (e.g. max_price paired with is_price_filter_enabled) are only implied in the schema rather than explained here, but that is a narrow miss given the schema already documents each field.

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%, so the baseline is 3, but the description adds meaning the schema does not: the omit-don't-set-false convention that governs all 25 optional arguments, and the passport naming normalization rule (visa-table names, aliases normalized) that prevents enum-mismatch failures. That is real semantic content beyond the field-level descriptions.

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 ('Recommend') and resource ('destinations') with a scoping constraint ('from a departure airport'). It also draws a boundary against out-of-scope use ('Do not use this for live flight tickets'), so an agent can separate it from destinations.info, destinations.resolve, and visa.check without opening any schema.

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?

Explicitly says when to use it ('Use this whenever the traveler asks where to go') and when not to, plus a concrete rule set for filter handling: only set filters the traveler explicitly asked for, omit everything else so defaults apply, never set a filter false by implication, and don't enable direct flights unprompted. This is exactly the when/when-not/alternative guidance the dimension asks for.

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