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

Annotations already mark this as non-read-only and open-world, and the description adds value by stating the human-confirmation gate and the caveat that checkout creation is not payment proof. This gives agents useful behavioral context beyond the structured fields, with no contradiction.

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 only two sentences, with the condition front-loaded and the 'not payment proof' caveat earning its place. There is no redundant or filler content.

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 tool with no output schema, a free-form details object, and a 9-value service_id enum, the description leaves the agent without guidance on return values or how to populate details. It covers the gating condition but not enough to call the tool correctly beyond the literal schema.

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 0%, so the description must carry parameter meaning. It indirectly maps 'human explicitly agrees to pay' to user_confirmed_payment and 'product-specific checkout details' to details, but it says nothing about service_id, its enum values, or the expected structure of details.

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 ('route') and resource ('product-specific checkout details to the verified product gateway'), clearly stating what the tool does. It also semantically distinguishes the tool from the read-oriented siblings (discover/get_*) by framing it as the checkout-creation action.

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 first clause gives an explicit precondition: use only after the human explicitly agrees to pay. However, it does not name alternative tools or provide when-not-to-use guidance, so it stops short of a full routing rule.

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