Marlo MCP

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

No annotations are provided, so the description carries the full burden of behavioral disclosure. The description 'create a new vessel' implies a write/mutation operation, but provides no information about permissions required, whether this is a destructive operation, what happens on success/failure, or any rate limits. For a creation tool with zero annotation coverage, this is completely inadequate.

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 extremely concise at just three words. While this conciseness comes at the expense of completeness, the description is front-loaded and contains zero wasted words. Every word in 'create a new vessel' contributes directly to the core purpose statement.

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 input schema (with 1 parameter that contains over 100 nested properties, 8 of which are required), no annotations, and no output schema, the description is completely inadequate. A creation tool with such a complex schema needs much more context about what data is required, what happens after creation, and any behavioral constraints.

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 schema description coverage is 0%, meaning none of the parameters have descriptions in the schema. The tool description provides no information about parameters whatsoever, not even mentioning that a complex 'vessel' object is required. With 0% schema coverage and no parameter information in the description, this fails to compensate for the documentation gap.

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 'create a new vessel' is a tautology that essentially restates the tool name. It provides a verb ('create') and resource ('vessel'), but lacks any specificity about what creating a vessel entails in this context or how it differs from other vessel-related operations. It doesn't distinguish from sibling tools like 'get_vessels' or 'get_vessel_details'.

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 absolutely no guidance on when to use this tool versus alternatives. There's no mention of prerequisites, when this operation is appropriate, or what other tools might be used for related operations. Given the complex schema with many required fields, this lack of usage guidance is particularly problematic.

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