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

With no annotations provided, the description fully carries the burden of behavioral transparency. It discloses data availability since 2021-08-10, that only position changes are stored (stationary gaps possible), and the constraint that 'to' must be within 30 days of 'from'. This provides essential behavioral context beyond 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?

The description is two sentences, efficiently front-loaded with the purpose, then details. Every sentence adds value without redundancy. It is well-structured and easy to parse.

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?

Given the complexity of the tool (multiple identification methods, time range options, data constraints) and the presence of an output schema, the description is complete. It covers all essential aspects: identification, time range specification, data availability, and behavioral notes on gaps. No gaps in context.

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%, but the description adds significant meaning by explaining the mutual exclusivity of identifiers (exactly one of mmsi, imo, uuid), the relationship between days and from/to (mutually exclusive), and the data availability date. This goes beyond the schema descriptions, providing critical usage logic.

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 clearly states 'Return the historical track (ordered position records) for a single vessel', specifying a specific verb and resource. It distinguishes from sibling tools by detailing unique identification methods (MMSI, IMO, UUID) and time range options (days or from/to), making it clear that this tool is for historical track retrieval.

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 provides explicit context for when to use the tool (historical track of a single vessel) and outlines specific constraints (exactly one identifier, use either days or from/to, not both, max 30-day range). While it does not explicitly state when not to use it versus siblings, the context is clear and helpful for correct invocation.

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