Marlo MCP

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

With no annotations provided, the description carries full burden but offers no behavioral details. It does not disclose whether this is a read-only operation, if it requires authentication, how results are returned (e.g., pagination), or any rate limits, making it inadequate for safe and effective use.

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 with three words, which is front-loaded but under-specified. While not verbose, it lacks necessary detail, making brevity a detriment rather than a strength in this context.

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 (12 parameters, no output schema, no annotations), the description is severely incomplete. It does not address parameter usage, return values, error handling, or behavioral traits, leaving critical gaps for a tool with significant input requirements.

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 description coverage is 0%, and the description provides no information about parameters. The input schema includes 12 parameters (e.g., client_status, page, filter), but the description does not explain their purposes, formats, or how they affect the listing, failing to compensate for the lack of schema descriptions.

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 'list all invoices' restates the tool name with minimal elaboration, making it a tautology. While it indicates the verb 'list' and resource 'invoices', it lacks specificity about scope or differentiation from sibling tools like 'get_invoice_details' or other list tools, falling short of clear purpose definition.

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?

No guidance is provided on when to use this tool versus alternatives. It does not mention prerequisites, context for filtering invoices, or comparisons to sibling tools like 'list_all_bills' or 'get_invoice_details', leaving the agent without usage direction.

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