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

Annotations already indicate readOnly=false and idempotent=false, so the description does not need to restate mutation. It usefully explains that the tool verifies payment and records revenue, but it does not disclose side effects like duplicate settlement or what happens if the sale was already settled.

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 compact sentences with no filler. The most important call condition is front-loaded, and every sentence contributes to understanding how and when to invoke the tool.

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?

With an output schema present and all parameters documented, the description covers the essential workflow well. A minor gap is not explaining why payment_required is needed or how to confirm a product is actually listed, but these are covered by schema and sibling tools.

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 description coverage is 100%, so the baseline is 3. The description reinforces that product_id and PAYMENT-SIGNATURE are the key call inputs, but it does not meaningfully elaborate beyond the schema, especially around payment_required.

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 uses a specific verb and object: verify and settle a buyer's x402 payment for a listed composite product and record revenue. This clearly distinguishes it from sibling tools like swarm.research or x402.verify by focusing on settlement and revenue recording.

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 the timing and required inputs: call with product_id and PAYMENT-SIGNATURE after the buyer pays. It does not name alternative tools or exclusions, but the sequencing guidance is clear enough for correct invocation.

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