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

Annotations only supply readOnlyHint=true, so the description carries the real behavioral burden and does: newest-first ordering, the unattributedTripsCount treatment of voyages where the caller is not crew, the caveat that figures are self-logged and unverified, ID format, and total aggregation scope. This is well beyond what the annotation declares.

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?

Everything is front-loaded and every clause earns its place, but it is delivered as one dense run-on paragraph mixing purpose, field semantics, filtering, and caveats. Slight structural grouping would improve scanability without cutting 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?

There is no output schema, so the description must describe the return shape and it does exhaustively: field-by-field (loaCm, ISO 3166-1 alpha-2 countries, sea areas in voyage order, distances in meters, durations in seconds), plus totals scope and ordering. Nothing needed to call or interpret the tool is missing.

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 0% and the description compensates fully for all three parameters: role accepts 'all'/'skipper'/'crew' and filters rows, while from/to are YYYY-MM-DD and bound rows inclusively by start date. The meaning the schema cannot express (inclusive, start-date-based, row filtering) is stated.

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+resource framing ('The caller's sailing résumé') and immediately scopes it against the sibling read tools: it is one row per voyage the caller sailed, not the general trip/track/leg readers. An agent can tell it apart from trip_read or stats 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?

It gives clear usage context ('the record a charter company asks for before handing over a boat') and explains what happens under each filter, but never explicitly names an alternative sibling (e.g. trip_read, stats) or states when NOT to use it. Context is clear; exclusions are absent.

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