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 the return type ('List of CDN zones with details') but lacks critical behavioral details: whether this is a read-only operation, if it requires authentication, potential rate limits, pagination handling, or what 'details' include. For a list operation with zero annotation coverage, this is a significant gap in transparency.

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 two brief sentences that are front-loaded: the first states the action, the second clarifies the return value. There is zero wasted text, and both sentences earn their place by providing essential information without redundancy.

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 simplicity (0 parameters, no output schema, no annotations), the description is minimal but incomplete. It lacks behavioral context (e.g., safety, auth needs) and doesn't specify the format or structure of the returned 'details'. For a list operation that might return sensitive or complex data, more guidance would help the agent use it correctly.

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 has 0 parameters with 100% schema description coverage (empty schema). The description doesn't need to explain parameters, and it correctly avoids mentioning any. It focuses on the action and return value, which is appropriate for a parameterless tool. Baseline is 4 when no parameters exist.

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 ('List') and resource ('all CDN zones'), making it immediately understandable. It distinguishes from siblings like 'get_cdn_zone' (singular) and 'get_cdn_zone_summary' by indicating it returns multiple zones. However, it doesn't explicitly differentiate from other list tools like 'list_domains' or 'list_kubernetes_clusters' beyond the resource name.

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, context for usage, or compare with sibling tools like 'get_cdn_zone' (for single zone details) or 'get_cdn_zone_summary' (for aggregated data). The agent must infer usage from the tool name alone.

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