Vultr 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. It states the tool retrieves details but doesn't mention whether this is a read-only operation (implied by 'Get'), authentication requirements, error handling (e.g., for invalid IDs), rate limits, or response format beyond 'Invoice details including line items'. For a tool with zero annotation coverage, this leaves significant gaps in understanding its behavior.

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 well-structured and front-loaded with the core purpose, followed by brief sections for Args and Returns. It avoids unnecessary words, though the Returns section could be more specific (e.g., mentioning fields like amount, date). Overall, it's efficient and easy to scan.

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 tool's low complexity (single parameter, no output schema, no annotations), the description is minimally adequate. It covers the basic purpose and parameter but lacks details on usage context, behavioral traits, and output specifics. For a simple read operation, this might suffice, but it doesn't fully compensate for the absence of annotations or output schema.

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 description adds meaningful context for the single parameter 'invoice_id' by specifying it as 'The invoice ID', which clarifies its purpose beyond the schema's type declaration (string). With 0% schema description coverage and only one parameter, this adequately compensates, though it doesn't detail format constraints (e.g., numeric, alphanumeric).

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 purpose with a specific verb ('Get details') and resource ('a specific invoice'), making it immediately understandable. However, it doesn't differentiate from potential siblings like 'list_invoices' or 'get_invoice_items' that might exist in the broader context, though those aren't in the provided sibling list.

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 alternatives. It doesn't mention prerequisites (e.g., needing an existing invoice ID), exclusions, or comparisons to other tools like 'list_invoices' for browsing. The agent must infer usage solely from the name and description.

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