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

With no annotations, the description does real work: it discloses that creation returns an approve URL and order id, and that a separate capture call is required after human approval. It does not say whether the order expires or what failure modes look like, but the human-in-the-loop payment semantics are clear.

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?

Three short sentences, front-loaded with the purpose and followed by return behavior and the required next step. Every sentence earns its place with no repetition.

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 one-parameter creation tool with no output schema, the description covers the return values and the essential follow-up call. The remaining gap is minor: no mention of order expiry or account prerequisites, but an agent has enough to invoke it correctly.

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 already 100%, and the single pack enum documents each option, its price and the default. The description adds only the phrase 'high-res figure credits' and does not restate or enrich the pack semantics, so this is the baseline 3.

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?

It states a specific verb, resource and domain: create a PayPal Checkout order for high-res figure credits. That scope clearly separates it from create_usdc_order and build_usdc_solana_tx without the reader opening any 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?

The two-step flow is explicit: create the order, hand the approve URL to the human, then call capture_paypal_purchase after approval. It does not explain when to choose PayPal over the USDC siblings, but the payment-rail distinction is implied by the name and the follow-up instruction.

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