List Payments

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

Annotations already indicate read-only, idempotent, and non-destructive behavior. The description adds the behavioral constraint that one of booking_id or since_utc is required to keep results bounded, which is not obvious from the schema (no required fields). This goes beyond annotations by disclosing a practical API requirement. It does not mention pagination or response format, but the annotations cover the safety profile.

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?

The description is a single, well-structured sentence that front-loads the core purpose ('List payments') and then provides parameter usage. Every clause adds necessary information without redundancy. It is highly concise and scannable.

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 simple list operation with strong annotations (read-only, open-world, idempotent), the description provides sufficient context for selection and invocation. It omits details about response format or pagination, but no output schema exists and the parameter guidance is adequate. The tool is straightforward enough that this is acceptable, but a note about what fields are returned would push it to 5.

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 67% (two of three parameters have descriptions). The description adds the crucial 'one is required' constraint, which is not captured by the schema's required list. It also reinterprets since_utc as 'recent activity' and booking_id as 'for one booking', reinforcing the schema descriptions. However, it does not explain the limit parameter, which remains undocumented in both schema and description. The added constraint elevates it above 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?

The description clearly states 'List payments (guest → you)' with a specific verb and resource, and the direction clarifies the scope. It distinguishes from sibling tools like list_deposits and list_refunds by focusing on payments, not other transaction types. The additional parameter context (booking_id or since_utc) further clarifies what the tool does.

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 provides clear guidance on when to use this tool: 'Provide booking_id (for one booking) or since_utc (recent activity) — one is required to keep results bounded.' This explains the typical use cases and imposes a necessary precondition. However, it does not explicitly mention alternatives like list_deposits or list_refunds, so while the context is clear, it lacks explicit 'when not to use' guidance.

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