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

Annotations already declare readOnlyHint, idempotentHint, openWorldHint and destructiveHint=false, so safety is covered. The description adds quota and freshness context — 24-hour lag on free accounts, a 1 square degree box, 1,000 credits a month, live on paid plans — but it is ambiguous whether these limits describe this tool's output or the data platform generally, and it never says whether the listing itself consumes credits.

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?

The first sentence is a long stacked clause that front-loads content but reads awkwardly. The 'Free. Free accounts too:' fragment and the pricing paragraph are informative but sit oddly in a tool description and read more like account_usage material.

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 burden of describing the return shape, and it does so explicitly (licence, credit to show, coverage, history depth). The tier/limit paragraph is a partial detour, but an agent has enough to call this no-argument tool correctly.

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 there is no parameter semantics to add beyond the empty schema; baseline 4 applies. Nothing in the description misleads about inputs.

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 identifies a specific resource — the data sources behind the answers — and enumerates what each entry contains (licence, credit line, coverage, history depth). It lacks an explicit verb and never contrasts itself with the vessel/port siblings, but an agent can tell this is a provenance/attribution lookup rather than a query tool.

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?

There is no when-to-use guidance, no statement of prerequisites, and no exclusions or alternatives named. The reader must infer that this is for attribution/licensing lookups from the content of the returned fields alone.

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