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

Annotations already declare non-read-only, non-idempotent, open-world, non-destructive. The description adds genuinely new behavior: creation triggers a customer checkout flow that collects the shipping address, and requires a documented terms acknowledgement gate. What it does not state is whether repeated calls create duplicate links or what the tool itself returns (a URL?), which matters given idempotentHint=false.

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?

Front-loaded with the action, then the flow, then the gating condition. The quoted terms text is long but is verbatim-required content, so it earns its space; the structure is tight overall.

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 checkout-creation tool with no output schema and partial param coverage, the prerequisite gate and customer-facing flow are well covered. The missing piece is the return value (presumably a checkout URL) and duplicate-call behavior, which an agent calling a non-idempotent creation tool would want.

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?

With only 40% schema description coverage, description needs to compensate. It does explain customer_accepted_terms precisely by quoting the exact sentence the customer must agree to, which adds real value beyond the schema. However, quote_id is undocumented anywhere and the description adds no detail on color, qty, or how the options map to the link's charges.

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 ("Create a payment link for a quote") and immediately explains the customer-facing effect: they pay and enter their shipping address on the linked page. An agent can distinguish this from sibling tools like price_quote or quote_file without opening the schema.

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?

Gives an explicit precondition (show the price, get explicit agreement to the exact terms sentence) and names the alternative when the condition is not met: "Otherwise give them the order_url from quote_file instead." This is textbook when/when-not with a named sibling.

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