Purchase new virtual machine

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

Annotations already declare this is not read-only and not destructive, so the description adds useful behavioral context beyond that: a setup-failure fallback via hPanel and the automatic use of the default payment method. It does not disclose cost implications, irreversibility, or asynchronous behavior, but the additional details meaningfully inform the agent.

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 compact and front-loaded with the core purpose, followed by actionable fallback and payment behavior. Every sentence earns its place; the final sentence reinforces the tool's scope without bloating the text.

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 purchase operation with no output schema, the description covers important edge behavior (manual setup fallback, default payment) but omits what the response contains, whether the operation is asynchronous, and what the required 'setup' parameter should contain. The agent has enough to begin, but meaningful gaps remain for a reliable call.

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 100%, so the baseline is 3. The description's payment-method default line duplicates what the schema already says, and it adds no clarifying detail about the ambiguous 'setup' parameter or how to obtain item_id. It neither hurts nor significantly improves 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 states a specific verb and resource: 'Purchase and setup a new virtual machine' and explicitly says 'Use this endpoint to create new VPS instances.' This distinguishes it from sibling tools like VPS_setupPurchasedVirtualMachineV1 and domains_purchaseNewDomainV1 by clarifying it creates VPS instances rather than merely performing setup or purchasing other resources.

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 clear usage context with 'Use this endpoint to create new VPS instances' and gives practical guidance about what to do if setup fails. It does not explicitly state when not to use it or contrast it with related billing/setup tools, but the purpose statement is strong enough for an agent to select it appropriately.

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