Check a vessel (no key)

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

Annotations already cover the read-only/idempotent/open-world profile, and the description adds genuinely new behavioral facts: a 100 req/hour per-IP rate limit, no-key operation, and that only the VERDICT SUMMARY is returned. That is more than the structured fields convey.

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?

Four front-loaded sentences, each carrying distinct load: what it screens, what it scores, the no-key/rate-limit constraint, and the output scope plus sibling routing. No filler.

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 compensates by stating the return is VERDICT SUMMARY only and pointing to the tool that returns full matches. Auth, rate limit, and scope are all covered, so nothing needed to invoke it correctly is missing.

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% and the single parameter carries its own pattern and description, so the schema does the heavy lifting. The description restates 'by IMO number' but adds no format or validation detail beyond it, matching the baseline for fully-documented params.

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 (screen/check) and resource (one vessel by IMO number) and lists exactly which sanctions lists are consulted. It explicitly distinguishes itself from the sibling screen_vessel, so an agent can route without opening either schema.

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?

Gives an explicit when-to-use condition ('works with no API key') and names the alternative (screen_vessel) plus the condition that selects it (need for every match with source list and confidence class). Nothing 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.