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

With no annotations, the description carries the full burden. It discloses the scope (unpaid orders) and authentication requirement (Bearer + phone), which is useful. However, it doesn't explicitly state that this is a read-only operation or describe any side effects, rate limits, or error conditions. The title 'List' implies read-only, but the description doesn't add much beyond that and the scope.

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 two concise sentences that immediately state the core function and requirements. No filler or redundancy. It is front-loaded and every word contributes value.

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 tool with one parameter and no output schema, the description adequately explains what it returns (pending payment_requests) and the required context (unpaid orders, auth). It falls slightly short of a 5 because it doesn't provide any hint about the response structure or optional parameters, but overall it is sufficient for an agent to select and invoke 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 covers the lone parameter 'phone' with a clear description and pattern. The tool description repeats that phone is required but adds no new semantic information beyond the schema. Since schema coverage is 100%, the baseline of 3 applies.

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 lists pending payment requests associated with the customer's unpaid orders. It uses a specific verb ('list') and resource ('pending payment links'), and distinguishes itself from sibling tools like list_orders or get_cart which serve different purposes.

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: this is for pending payment_requests on the customer's unpaid orders, and it explicitly requires Bearer + phone. While it doesn't name alternative tools or exclusion scenarios, the context is specific enough for an agent to know when to invoke this tool over siblings.

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