Screen up to 50 vessels (API key)

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

Goes well past what the annotations convey: it is a blocking call ('wait for the results, up to two minutes'), it consumes quota ('each hull spends one screening unit'), that consumption is waived for hulls already screened today (explaining idempotentHint), and it requires ARCNAUTICAL_API_KEY. This is exactly the billing and latency context an agent must know before invoking.

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 sentences, zero filler, and front-loaded: what it does, what comes back, then the two constraints (auth key, unit cost). Each sentence carries distinct information.

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 still tells the agent the return shape (one verdict per hull plus batch status) and the timeout bound. Auth, cost, and idempotency behavior are all covered, leaving nothing material for correct invocation 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 description coverage is 100%, so the imos array and include_vetting toggle are already documented with patterns and semantics. The description reinforces per-hull cost and one-verdict-per-hull but adds no syntax or format detail beyond the schema, so the baseline 3 applies.

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 ('Batch-screen a list of IMO numbers') and pins the scope ('up to 50', one verdict per hull), which cleanly separates it from the singular sibling screen_vessel. The API-key qualifier in the title matches the description's key requirement.

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?

Batch framing implies you reach for this instead of the single-vessel screen_vessel when you have many hulls, and the 50-item cap is a usable boundary. However, it never explicitly names screen_vessel, get_screening or check_vessel as alternatives, nor states when this tool is the wrong choice.

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