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

With only readOnlyHint available, the description carries real behavioral nuance: unattributed voyages count only under 'all' and surface as `unattributedTripsCount`, and `ownedTripsCount`/`sharedTripsCount` split the log regardless of `role`. These are non-obvious semantics an agent could not infer from the annotation.

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-loads scope and return shape, then the role filter, then units. Dense but nearly every clause earns its place; the closing unit/type/ID-format reminders are slightly repetitive but useful given no output schema.

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 no output schema, the description compensates by enumerating every returned figure, its units (meters/seconds/knots-null), ordering rules (newest-first years, largest-first boats), ID format, and timestamp conventions. Nothing needed to interpret the result 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% in prose, but the description fully specifies `role`: default 'all', with 'skipper'/'crew' filtering every figure by the caller's role on each trip. That is meaning well beyond the bare const enum in the schema.

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+resource: computes the caller's lifetime logbook statistics over owned and shared trips, with totals, per-year, and per-boat breakdowns. Siblings (trip_read, leg_read, etc.) are entity CRUD tools, so this aggregate tool is unmistakably distinct.

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?

Gives clear context for use — whole-log aggregation including trips shared as linked crew, with the default role of 'all' — but never explicitly names when to prefer it over siblings like trip_read or states exclusions.

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