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

Annotations already declare readOnly=false, idempotent=true, destructive=false, so the safety profile is covered; the description earns credit for adding what they don't say — that the caller must hold a Gillby account and have given explicit consent, and that the operation deliberately does not assess navigation safety. The retry/requestId idempotency note restates the idempotentHint but adds the concrete mechanism.

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?

Three short sentences plus one unit line, with the core action and idempotency instruction front-loaded and no filler. The dense final unit line is information-packed and arguably should be attached to the fields it governs, but nothing is redundant.

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 write tool with annotations covering safety and no output schema, the description closes the remaining gaps an agent needs: auth/consent prerequisites, retry semantics, the navigation-safety scope boundary, field units and direction convention, and a note that the response includes data plus source/freshness metadata.

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 0%, so the description carries the burden, and it delivers the two conventions the schema cannot express: units (ft, kt, s, F, mi) and that directions are FROM, which disambiguates draftFt/ukcFt/speedKt and the from/to waypoints. It still says nothing about the meaning of optional fields such as via, status, activity, or notes, leaving self-explanatory enums and range bounds to 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 and resource ("Save a trip") that plainly maps to the create side of trip persistence, cleanly distinct from read siblings like get_my_trip and list_my_trips. It never names update_my_trip or save_my_place, so the create-vs-update boundary is left for the agent to infer from the name alone.

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?

"Supply a unique requestId and reuse it on retry" is genuine operational guidance for retry behavior, and the explicit account/consent prerequisite tells the agent what must be true before calling. What is missing is routing guidance: no statement of when to prefer update_my_trip over this tool, or that this is not the tool for route planning (check_route_conditions/plan_my_route).

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