Describe available vessel-registry datasets

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

With no annotations, the description carries the full burden of behavioral disclosure. It does disclose what information the tool provides (data source names, freshness, record counts, available fields), which gives the agent a clear sense of the output content. However, it does not explicitly state that the operation is read-only, nor does it mention any side effects or error conditions. For a metadata tool with no parameters, this is reasonably transparent but not exhaustive.

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 a single, concise sentence that front-loads the core purpose and enumerates the key metadata elements. It contains no filler or redundancy, making it highly efficient for an agent 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?

For a zero-parameter tool with no output schema and no annotations, the description is fairly complete. It tells the agent exactly what kind of information is returned (data source names, freshness, record counts, fields). One could argue it could also mention the structure or how to interpret the output, but given the simplicity of the tool, the description provides sufficient context for an agent to make an informed call.

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 tool accepts zero parameters, and the schema reflects that with 100% coverage (an empty schema). Since there are no parameters to document, the baseline of 4 applies. The description adds no parameter-related semantics because none are needed.

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 the tool's action ('Describes') and its resource ('available data sources'), and enumerates the specific kinds of metadata it returns (freshness, record counts, available fields). This is more specific than a generic statement, though it does not explicitly differentiate itself from the sibling tools (e.g., search_vessel_registries). However, the purpose is distinct enough that an agent can infer it is for obtaining dataset metadata rather than querying records.

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 no guidance on when to use this tool versus the siblings (search_vessel_registries, lookup_vessel, get_registry_stats) or when not to use it. There is no mention of prerequisites, context, or alternatives, so an agent must infer the appropriate use case from the purpose alone.

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