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

With no annotations, the description carries the full burden. It adds useful context like 'for free' and ties usage to prior paid responses, but it does not disclose potential error behavior, authentication needs, or whether the operation is read-only. This is adequate but not rich.

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, front-loaded sentence with no wasted words. It efficiently conveys the action, the payment context, and the parameter semantics.

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 retrieval tool with no annotations or output schema, the description covers purpose, parameter source, and cost. It could mention return format or limitations, but the tool's simplicity makes the description reasonably complete.

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 schema only says receipt_id is a required string. The description adds meaning by explaining that every paid response carries this ID, clarifying the parameter's origin and role. It does not specify format or validation, but it goes beyond what the schema provides.

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 re-fetches a previously paid result by receipt ID, using a specific verb and resource. It distinguishes itself from sibling extraction/parsing tools by focusing on retrieving past results rather than processing new input.

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 when to use the tool: when a receipt ID from a previous paid response is available. It provides clear context but does not explicitly name alternatives or state when not to use it, though the sibling list makes alternatives obvious.

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