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

Annotations already declare readOnly/idempotent/non-destructive, so the safety bar is lower; the description still adds value by disclosing null semantics for missing vessel measurements, the auth/consent precondition, the unit conventions, and that freshness metadata accompanies the payload. It stops short of saying whether settings can be absent entirely or how the three setting groups are keyed.

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, front-loaded with the purpose and scoping behavior. The units line is compact and genuinely useful rather than filler, though it reads as a bolted-on convention block rather than part of a single narrative.

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 zero-parameter read with no output schema, the description covers what is returned ('data and source/freshness metadata'), the null case, units, and auth requirements. The shape of the returned settings object and the distinction from the narrower vessel/notification getters remain unspecified.

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?

The tool takes zero parameters, so the baseline is 4 and there is no schema surface the description needs to compensate for. The unit and direction conventions it does state are output-side context rather than parameter meaning.

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: reading saved vessel, preference and notification settings. However, the sibling set contains get_my_vessel and get_my_notification_settings, and the description never clarifies how this aggregate read differs from those narrower tools, so the agent must guess which to call.

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?

Prerequisites are given ('Requires your Gillby account and explicit account consent'), which is real guidance about when the call will succeed. But there is no explicit when-to-use versus get_my_vessel, get_my_notification_settings or update_my_settings, so selection among the settings siblings is left to inference.

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