list_plans

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

Annotations already declare readOnlyHint, openWorldHint, idempotentHint, and destructiveHint false, so the safety profile is clear. The description adds that listing can be filtered by allowed_only, which provides behavioral context beyond annotations. It does not contradict annotations.

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 two sentences with no redundant words. The purpose is front-loaded in the first sentence, and the additional parameter guidance is placed immediately after.

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 simplicity of the tool (no output schema, two optional parameters, and clear annotations), the description covers the main action and one filter. However, the missing explanation of the type parameter and lack of alternative tool guidance make it somewhat incomplete for an agent to use confidently.

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%, so the description must compensate. It explains the allowed_only parameter ('to see plans permitted by policy') but completely omits the type parameter. This leaves one parameter undocumented, which is a significant gap for a two-parameter tool.

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 states 'List Vultr plans' which is a clear verb+resource pair. The resource 'plans' is distinct from sibling tools like list_instances or list_regions, providing implicit differentiation. However, it does not explicitly state that this tool is for listing available subscription plans, which might assume domain knowledge.

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 mentions setting allowed_only to true for policy-permitted plans, giving some usage context. However, it lacks explicit guidance on when to use this tool versus alternatives, such as list_os or list_regions, and does not include any when-not-to-use conditions.

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