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

Annotations already declare readOnly, idempotent, openWorld, and non-destructive, so the safety profile is covered. The description adds meaningful context beyond that: it discloses source/freshness metadata in the return and warns that empty results are not evidence of safety, though it says nothing about latency, coverage limits, or data currency beyond 'availability.'

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-loaded with purpose, then a caution, then a compact units/metadata line. Nothing is redundant, though the units line is somewhat boilerplate relative to this tool's content.

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 mention of source and freshness metadata is a useful partial substitute, and the empty-report caveat is valuable. However, the nested bbox/category parameters remain completely unexplained, leaving an agent guessing at accepted formats and values.

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% and the single parameter is a nested object with bbox and category subfields that are entirely undocumented in both schema and description. The units line ('ft, kt, s, F, mi; directions FROM') describes data conventions, not what bbox format or category values are accepted.

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: 'Reported derelict vessels from the published agency dataset,' which is distinct from siblings like find_wrecks or get_hazards. It does not explicitly contrast itself with those closest siblings, so it stops short of a 5.

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?

The caveat 'Empty reports do not establish safe conditions' implies usage context (do not use absence as proof of safety), but there is no explicit when-to-use guidance or named alternatives such as find_wrecks, get_hazards, or get_navigation_notices.

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