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

Annotations already declare readOnlyHint=true and openWorldHint=false, so safety and locality are covered. The description adds that the payload mixes live inventory ('live discounted boats', 'five best deals') with static reference content, hinting at an aggregated, freshness-sensitive response, but says nothing about cost, latency, or how the live data behaves — and the content manifest largely duplicates what the output schema already shows.

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?

It is a single front-loaded sentence whose head phrase ('One destination in depth') frames everything that follows. The trailing comma-list is long and dense — 'the site pages' is a vague closing item — but every element conveys a real content category rather than filler.

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 an output schema, two fully documented enum parameters, and read-only annotations, the description only needs to tell the agent what class of data comes back, which the content manifest does. The remaining gap is guidance on when to prefer this aggregated call over the cheaper single-purpose siblings.

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 parameters carry enum values plus descriptions ('Destination slug', 'Language of titles, texts and stop names'). The description contributes nothing about the country slug format or the effect of the lang flag on returned stop names, so the baseline 3 applies.

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 enumerates exactly what 'one destination in depth' returns — sailing area, bases, winds, month-by-month season, deals, market prices, routes, site pages — which clearly separates it from list_destinations (a list) and from the narrow siblings like prices_by_month, get_route, or search_deals. It lacks an explicit verb and never names the siblings it supersedes, so it stops short of 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?

Usage is implied by the content manifest: an agent can infer this is the tool for a full destination profile rather than a single-fact lookup. However, there is no explicit when-to-use/when-not statement and no routing to list_destinations for discovery or to the narrower tools when only one data slice is needed.

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