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

Annotations only declare readOnlyHint=true, destructiveHint=false, openWorldHint=false; the description adds the decisive operational facts that no payment is triggered and no contract is concluded, and that price, T&C and payment are deferred to the customer's own checkout. This is exactly the behavior an agent could not infer from the hints, and it is consistent with readOnlyHint rather than contradicting it.

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, front-loaded with what the tool does and immediately followed by the legal/behavioral constraint. No filler; every clause carries information.

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 two-parameter tool with no output schema, the description covers the action, the returned artifact (cart link), and the transactional limits. Nothing an agent needs to select and call it correctly is missing, and the missing output schema is compensated by naming the return artifact.

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% (product_id references get_hosting_packages, billing_cycle documents the cheapest-available fallback), so the schema carries the parameter burden. The description adds no additional parameter meaning, which is the baseline-3 case.

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?

Specific verb+resource ('Bereitet eine Hosting-Bestellung vor') plus the concrete artifact produced ('liefert einen fertigen Warenkorb-Link'). The hosting scope inherently separates it from the sibling prepare_domain_order without needing to be spelled out.

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 clearly frames the workflow boundary — it is the preparation step, and the customer completes the order themselves in the normal WHMCS checkout. It does not explicitly name alternatives or exclusion conditions (e.g. when to prefer a direct invoice flow), so it stops short of full when/when-not guidance.

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