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

Annotations already establish readOnlyHint=true and idempotentHint=true, so the safety profile is covered. The description adds valuable behavioral context beyond annotations by listing the exact return components (history, average, percent, verdict, drop-list status) and the required input source, which is especially important given there is no output schema. No contradiction.

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 carry all essential information: the purpose, the output list, and the input source. The most critical detail (what the tool returns) is front-loaded, and there is zero filler or repetition of schema content.

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 read-only, two-parameter tool with no output schema, the description adequately covers the return value composition and input provenance. It does not define the 'verdict' logic or response format, and it omits the optional cabin parameter in prose, but the schema covers the parameter and the tool's simplicity keeps these gaps minor.

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 both id and cabin are already documented in the schema. The description reinforces that the id comes from searchCruises, which the schema example also shows, but it adds no meaning for the cabin parameter. With high schema coverage, the baseline of 3 is appropriate.

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 opens with a specific verb ('Judge') and resource ('one sailing's current fare'), then enumerates the concrete outputs: six-month history, average, percent above/below, verdict, and price-drop membership. This clearly differentiates it from sibling tools like compareSailings (multi-sailing comparison) and getPriceDrops (likely just the drop list).

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 states the input must be a sailing id from searchCruises, implying a sequential workflow. However, it gives no explicit guidance on when to choose this tool over getPriceDrops (which overlaps on the price-drop list) or compareSailings, and provides no exclusions or prerequisites beyond the id source.

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