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

With no annotations the description carries the full burden and does so well: it discloses the async human-approval flow for PayPal, that crypto payments are auto-detected on-chain with no further call, and critically that retrying with the same idempotency_key is safe. This is exactly the operational behavior an agent needs before calling a payment-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?

Purpose is front-loaded in the first sentence, followed by rail behavior and per-product requirements. It's dense but every sentence carries actionable information; no filler. Slightly monolithic with no paragraph breaks for the three distinct concerns.

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?

There is no output schema, so the description's disclosure of approve_url and next_action.amount_due is essential and present. For a 7-parameter tool with nested objects and two payment rails it is largely complete, though a note on the non-PayPal/crypto success response would close the last gap.

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 0%, so the description must compensate, and it does for most fields: payment_rail semantics (PayPal vs crypto), idempotency_key's retry-safe behavior, and the per-product mapping of shipping/delivery.wallet_address/details. items and quote_id are covered only implicitly by 'from a quote or items', leaving a small gap.

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+resource ('Create an order from a quote or items') and immediately distinguishes the two input modes plus the two payment rails. An agent can tell it apart from create_quote and create_purchase_intent because the order object and its rails are named explicitly.

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?

Clear context on which rail does what (PayPal = human approve_url, crypto = automatic) and what each product type requires (shipping, delivery.wallet_address, details), plus the follow-up step to poll get_order_status. It stops short of explicitly contrasting create_order with create_quote/create_purchase_intent, so no true when-not guidance.

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