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

Annotations already declare readOnlyHint, openWorldHint, idempotentHint, and non-destructive behavior. The description adds meaningful context beyond annotations by specifying exactly what data is included (AIS self-reported data, neural-network-inferred gear/ship types, official registry records, AIS coverage stats) and noting the inference source. This helps the agent set expectations about data provenance without contradicting 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?

The description is efficiently written, front-loaded with the core purpose, and every sentence contributes information. The parenthetical list of data categories is dense but clear, and the final sentence about UUID provenance is essential guidance. No filler or redundancy.

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 the input provenance, the full scope of returned data, and the inference method. An output schema exists to document return format, so the description does not need to explain response structure. Nothing needed for correct invocation 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 for the single parameter vessel_id is 100%, including a detailed description and example. The description adds value by clarifying that the UUID is the Global Fishing Watch vessel UUID and that it comes from gfw.vessel.search, reinforcing correct parameter sourcing beyond the schema.

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 states a specific verb ('Retrieve') and resource (complete identity and activity profile for a specific vessel) and distinguishes itself from gfw.vessel.search by explicitly noting the input is a vessel UUID obtained from that search tool. The data categories are enumerated, leaving no ambiguity about what the tool does.

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 clear context for when to use the tool: when you have a vessel UUID and need a complete identity/activity profile. It explicitly directs users to gfw.vessel.search for obtaining UUIDs, which is a useful dependency guideline. It does not explicitly exclude alternatives like gfw.vessel.fishing_events, but the scope is unambiguous.

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