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

Annotations already indicate read-only, idempotent, and non-destructive behavior. The description adds the returned attributes and the time/area constraint but does not disclose behavioral nuances like AIS data coverage gaps, coordinate order requirements, maximum result limits, or units for speed/heading. It supplements the annotations modestly without contradicting them.

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?

Two sentences, front-loaded with verb and scope, followed by a compact return-field list. No redundant phrasing or reiteration of the tool name; every clause adds 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?

The description covers the core query semantics and output fields, which compensates for the lack of an output schema. However, it omits important context such as coordinate format, units (e.g., knots, degrees), bounding-box ordering expectations, and any limits on the look-back window. For a moderate-complexity query tool this is adequate but not comprehensive.

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?

Only 1 of 5 parameters (hours) has a schema description, leaving lat_min/lat_max/lon_min/lon_max as bare numbers. The description mentions 'geographic area and time window' but does not clarify bounding-box semantics, coordinate format, units, or that all four bounds are required. The hours default conveyed by the schema is not restated. Schema coverage is only 20%, so the description should carry more parameter meaning; it largely fails to.

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 uses a specific verb ('Query'), names the exact resource ('AIS vessel positions'), and scopes it by geography and time window. It also enumerates the returned fields, making the purpose unambiguous. Among siblings like query_aircraft and query_ports, the resource and scope clearly set this tool apart.

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 no guidance on when to choose this tool versus related sibling tools (e.g., query_ports, query_aircraft), nor any conditions or exclusions. It only states the operational scope (bounding box and look-back window), which falls short of explicit usage direction.

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