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

With no annotations, the description carries the full behavioral burden. It discloses that no key is needed and that plans include hourly/daily USD prices, plus a deployment URL. However, it doesn't state whether the optional type parameter filters results, what the default response includes, or return format/pagination.

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?

Two sentences with no filler: the first states the core purpose, the second adds auth and deployment context. Every sentence earns its place.

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?

For a one-parameter list tool, the description covers the resource and auth, but the optional type parameter's effect and default behavior are left unstated. Without an output schema, the description should clarify what the agent can expect in the response.

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 names VPS and GPU, which map to the enum values, but it doesn't explicitly connect the type parameter to filtering or explain behavior when omitted. This is partial compensation only.

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 identifies the resource ('Singularity Cloud machine plans') and its content (VPS/GPU types, hourly and daily USD prices). It lacks an explicit verb, but the tool name 'cloud_list_plans' supplies it. It doesn't explicitly differentiate from sibling list tools, but the resource type 'plans' distinguishes it from instances, pods, and processors.

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 when-to-use guidance or alternatives are mentioned. 'No key needed' hints at public access, but there is no guidance about choosing this over cloud_list_pods, cloud_pod_catalog, or browse_marketplace. An agent would have to infer when this tool is appropriate.

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