list_payments

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

Beyond the readOnlyHint annotation, the description discloses important behaviors: only SUCCESS payments are returned, card transaction details are never included, and the 'fields' parameter narrows the response (cannot widen past the allowlist). It also mentions default limit and date window behavior, adding significant value beyond the 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?

The description is concise and well-structured, with the main action in the first sentence, followed by essential constraints and a clear exclusion note. Every sentence adds substantive information with no redundancy or fluff.

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 that an output schema exists, the description does not need to explain return values. It covers all key operational aspects: default date window and limit, successful-payment filter, card-detail exclusion, field filtering behavior, and unsupported actions. This is a complete and self-sufficient description for an agent to use the tool 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?

The input schema has no parameter descriptions (0% coverage), so the description must compensate. It explains the 'fields' parameter semantics in detail and mentions the 'limit' default, and 'date window' covers date_from/date_to. While it doesn't explain date parameter formats or exact names, it provides enough context for an agent to infer usage.

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 the tool's function: 'List payments within an optional date window', with a specific verb and resource. It further distinguishes itself from siblings by specifying 'Only result=SUCCESS payments' and 'Card transaction details never included', making the scope unambiguous.

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 context on when to use the tool: for listing successful payments in a date range. It also explicitly states exclusions: 'This tool does NOT support payment capture, refund, or void actions.' However, it does not name alternative tools (e.g., list_refunds) that should be used for those actions, so it falls short of a 5.

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