billing_createPurchaseOrderV1

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

With no annotations, the description carries full burden. It discloses that the endpoint only places orders and uses default payment method if none provided. It does not mention idempotency, rate limits, or error handling, which are important for a mutation tool.

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 multiple sentences but each adds meaning: purpose, catalog reference, default behavior, and separation of concerns. It is front-loaded and not verbose.

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 3-parameter tool with no output schema, the description covers purpose, parameter sources, default behavior, and post-order actions. It lacks response format details but is adequate for agent use.

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 coverage is 100% with descriptions, but the description adds value by explaining how to find item_id via the catalog endpoint and clarifying payment_method_id optionality and default behavior.

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 it creates a purchase order for any Hostinger product, distinguishing it from product-specific purchase endpoints among siblings (e.g., VPS_purchaseNewVirtualMachineV1, domains_purchaseNewDomainV1). It uses specific verbs and 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 explicitly says to use this endpoint to purchase any product and provides context: it only places the order, not provisioning. It references the catalog endpoint for item IDs. However, it does not explicitly exclude specific scenarios or name alternatives.

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