Vultr MCP

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

No annotations are provided, so the description carries full burden. It mentions pagination info, which is useful, but lacks details on permissions, rate limits, sorting, filtering, or error handling. For a list operation with zero annotation coverage, this is insufficient behavioral 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 front-loaded with the core purpose, followed by structured sections for args and returns. It's efficient with minimal waste, though the 'Args' and 'Returns' labels could be integrated more smoothly into the flow.

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 no annotations, 0% schema coverage, and no output schema, the description is incomplete. It covers basic purpose and one parameter but lacks details on behavior, full parameters, output structure, and sibling differentiation, making it inadequate for a list tool in this 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 description coverage is 0%, but the description adds meaning by explaining 'per_page' as 'Number of items per page' and noting the default. However, it doesn't cover constraints like min/max values or other potential parameters (e.g., page number, filters), leaving gaps in 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 clearly states the verb ('List') and resource ('invoices'), making the purpose specific and understandable. However, it doesn't differentiate from potential siblings like 'get_invoice' (singular) or 'list_invoice_items', which are present in the sibling list, so it misses full distinction.

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. The sibling list includes 'get_invoice' (likely for a single invoice) and 'list_invoice_items', but the description doesn't mention these or any context for selection, leaving usage unclear.

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