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

Annotations already declare readOnlyHint=true and destructiveHint=false. Beyond that, the description adds useful behavioral context: what fields are returned, that company queries return every vessel under that company, and that it is part of the Maritime Reports add-on. No contradiction with annotations.

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 focused sentences with no filler. The primary outcome is front-loaded, the two lookup modes are clearly separated, and the add-on note is brief but relevant.

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?

The description covers purpose, output fields, and query modes, and an output schema exists. However, it does not state whether the seven optional parameters are mutually exclusive or can be combined, which is a meaningful gap for a tool with multiple query modes. Pagination or result limits for company-wide queries are also not mentioned.

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%, so the schema already documents each parameter. The description adds value by grouping parameters into two semantic modes (vessel lookup vs company reverse-lookup) and clarifying what company-name parameters return. It does not add new format details, but supplements the schema meaningfully.

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 names a specific verb and resource: reveal the commercial control behind a vessel, listing beneficial owner, operator, technical manager, commercial manager, P&I club, and flag. This clearly distinguishes it from sibling tools like get_vessel_info or intel_companies by focusing on the ownership/management chain.

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 gives explicit usage patterns: look up by imo or name, or reverse-lookup by company name to list controlled vessels. It clearly explains when each parameter mode is appropriate, though it does not explicitly compare against alternatives such as get_vessel or intel_companies.

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