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

Annotations already disclose destructiveHint and openWorldHint. The description adds that CNY WeChat Pay and Alipay return a one-time device-aware payment link, which is useful behavior. However, it does not explain Stripe behavior, potential side effects, or lifecycle of the payment request. No contradiction with annotations.

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, with the purpose front-loaded. No filler or repetition. Every word adds value, earning the highest score.

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?

Given the 3-parameter tool with full schema coverage, output schema, and annotations, the description covers the core operation and a key per-method nuance. It is concise but missing explicit notes about Stripe behavior or prerequisites beyond ownership. Still sufficient for an agent to invoke 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 description coverage is 100% with each parameter clearly described. The description adds a nuance about payment methods returning a link, but does not go beyond the schema for parameter formats or constraints. Baseline 3 is appropriate given full schema coverage.

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?

Clearly states the action: 'Create a payment request for a booking owned by the user_key account.' This is a specific verb-resource pair and distinguishes from siblings like create_booking or query_booking by focusing on payment. Also adds a unique behavioral detail for WeChat Pay and Alipay.

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 implies usage for initiating payment on an existing booking owned by the user_key account, giving clear context. It does not explicitly name alternatives or exclusions, but among siblings there is no other payment-specific tool, so the intended use is unambiguous.

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