vessel_track

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

With no annotations provided, the description takes full responsibility for disclosing behavior. It explicitly states that the track is a list of actual AIS reports with no interpolation, gaps are real, history exists only from server start, and an empty track means nothing was heard (not that the vessel didn't move). These details go far beyond the schema and give the agent crucial interpretive context.

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 three short paragraphs, each serving a distinct purpose: the purpose, the return structure and data authenticity, and the retention/empty-track nuance. It is front-loaded with the main purpose and contains zero filler. Every sentence adds value without being overly verbose.

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?

An output schema exists, and the description still clarifies the structure (data block, track list, oldest first). It covers edge cases like empty track and history retention. While it doesn't address error conditions or authentication, for a data-retrieval tool this is fairly complete. A minor gap is that it doesn't mention the query can be MMSI or name, but that is in the schema.

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?

The input schema already documents both parameters (hours, query) with full descriptions and constraints. The tool description does not add additional meaning about parameters; it focuses on the returned track. Given the 100% schema coverage, the baseline of 3 is appropriate; the description neither enhances nor detracts from parameter understanding.

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 opens with 'Where a vessel has been over the last few hours,' clearly indicating the tool returns historical positions for a single vessel. However, it limits the time range to 'a few hours' when the schema allows up to 90 days, creating a slight inconsistency. It does not explicitly distinguish from fleet_track, but the singular 'vessel' makes the scope obvious enough.

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?

There is no explicit statement about when to use this tool versus alternatives like fleet_track or vessel_details. The usage context is implied by the description and schema (exact MMSI or partial name), but no exclusions or alternative tool names are given, leaving the agent to infer when this is the appropriate choice.

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