Fetch a settlement receipt for a past purchase

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

With no annotations, the description carries full burden. It clearly states the tool is for retrieval and explains the two modes with prerequisites. However, it does not describe potential error conditions, auth requirements, or the format of the returned record. Slightly incomplete for full transparency.

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, no wasted words. The first sentence states the core purpose; the second gives precise usage instructions. Front-loaded and efficient.

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?

The description covers the essential usage paths for a tool with 4 parameters and conditional requirements. It does not describe the return value beyond 'durable settlement record,' but the tool name implies a receipt. A brief mention of what the response contains would complete it. Still largely sufficient for agent invocation.

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 description adds significant meaning beyond the input schema. It explains the conditional requirement relationships (e.g., 'Required with invoice_id') and groups parameters into two logical paths, which the schema alone does not convey. Schema coverage is 50%, but the description fully compensates.

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 starts with a clear, specific verb+resource: 'Retrieve the durable settlement record for a past purchase.' It distinguishes itself from sibling tools (like check_payment, confirm_payment) by focusing on settlement records and specifying two distinct use cases.

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 explicitly states when to use each parameter combination: for an offer purchase pass payment_intent_id + payer_secret; for an invoice pass invoice_id + preimage. It also references the source of these values (buy_offer, pay_invoice), providing clear contextual guidance.

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