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

Annotations already declare a safe, idempotent read, so the bar is lower; the description adds real value with dataset scale (~394,495 vessels), category coverage, and an explicit 'zero PII' constraint (no owner names or addresses). With no output schema, listing the returned fields also carries behavioral weight, though pagination behavior is left to the schema.

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 tight sentences, front-loaded with the action and lookup keys, then dataset scope, then return fields and the PII caveat. No filler sentences.

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 two-parameter dataset search with no output schema, the description supplies the domain, scale, returned fields, and an important PII limitation. Nothing an agent needs to call 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 description coverage is 100%, so the schema already documents both q and limit; the description's 'by name or official number' merely paraphrases q and adds nothing for limit. Baseline 3 applies when the schema does the heavy lifting.

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 (Search) and resource (USCG documented vessels) plus the two lookup keys (name or official number), which is a precise, distinguishable purpose among the many dataset-search siblings. An agent can tell this retrieves US vessel documentation data without opening the 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?

The description implies usage through the lookup keys and dataset scope, but never states when to prefer this tool or which sibling to use instead. There are no exclusions or prerequisite conditions, leaving routing to inference.

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