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

Annotations already declare readOnly, idempotent, non-destructive, and closed-world, so the safety profile is covered. The description adds genuine context beyond that: newest-first ordering, the 168-hour cap, the source-page field for imported rows, and the explicit 'missing hours are never interpolated' data-quality guarantee.

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 tight sentences with the core payload and ordering front-loaded, followed by the field list and the no-interpolation caveat. The home-page-map sentence is mildly tangential but does convey the typical window of interest.

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 carries the return-value burden and does so by enumerating the fields returned plus the imported-source-page exception. What remains uncovered – pagination, empty results, ordering ties – is minor for a small read-only two-parameter tool.

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 100%, so both ship and hours are already documented, and the description adds only the 'newest first' ordering and confirms the 168-hour ceiling. It does not explain the UUID vs slug distinction or how hours interacts with the stored data beyond what the schema states.

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 names a specific resource (a ship's saved hourly positions) with scope and ordering (up to 168 hours, newest first), which an agent can distinguish from list_ship_tracking or get_ship_metrics. It stops short of naming a sibling or stating a verb, but the payload is unambiguous.

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 only implied: the mention that the home page map draws each ship's last 3 days from these signals a typical retrieval use case. There is no explicit when-to-use, when-not, or routing to alternatives such as get_ship_metrics or list_ship_tracking.

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