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

With no annotations, the description carries the burden and does well: it discloses the server-side cart seeding, the returned checkoutUrl, human payment, that no payment is taken and no order placed, and that prices exclude VAT. It does not cover idempotency/duplicate-call behavior, cart lifetime, or auth requirements, which are meaningful gaps for a cart-mutating 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?

Two dense sentences that are front-loaded with the primary action and then the critical disambiguation (human pays, no order placed). Every clause carries information; nothing is wasted.

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?

With no annotations and no output schema, the description covers the essential return value (checkoutUrl) and the safety profile (no payment, no order). It is nearly complete for a 7-parameter tool, though it leaves cart persistence/expiry and repeat-invocation behavior unstated.

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, and it does reasonably: it explains packageKey (plan key), siteDomain (the hostname the hosting runs on), and names the remaining concepts (billing cycle, config options, add-ons, optional domain registration). It stops short of key formats, currency codes, or the distinction between 'siteDomain' and the optional 'domain' registration.

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?

States a specific verb and resource ('Start an order for a configured hosting plan') and immediately scopes it as cart-seeding rather than order placement. This clearly distinguishes it from siblings like quote, get_plan, and order_status.

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 makes clear this is the commit-to-checkout step that follows configuration ('for a configured hosting plan') and that a human completes payment. However, it never explicitly names alternatives (e.g., use quote to preview pricing before committing, order_status to track an existing checkout), leaving that routing to inference.

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