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

Annotations already indicate this is a non-read-only, non-destructive operation. The description adds the key behavioral detail that it does not charge, preventing misuse. It doesn't describe response formats or side effects beyond that, but the addition of the non-charging boundary is valuable and goes beyond annotations.

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 short sentences, front-loaded with the core purpose and a clear exclusion. Every word adds value, with no redundancy or filler.

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 mutation tool with no output schema, the description explains the action and non-charging behavior but does not mention what response the agent should expect or any required prerequisites beyond what the schema shows. It is adequate but lacks completeness for a tool that likely returns a prepared intent or ID.

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 provides full coverage of all six parameters with individual descriptions (e.g., 'Public offer ID', 'Opaque payer ID'), so the tool description does not need to repeat them. It adds no extra parameter context, but the baseline of 3 is appropriate given high schema coverage.

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's function with a specific verb ('Prepares'), resource ('PurchaseIntent object'), and purpose ('for future delegated payment adapters'). It also explicitly distinguishes itself by noting 'Does not charge', which sets it apart from other payment-related tools like create_checkout_link.

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?

It provides clear context that this is for preparing a payment intent for delegated adapters, and the explicit 'Does not charge' acts as a when-not-to-use warning for immediate charges. However, it does not explicitly name alternative tools or provide exhaustive when/when-not guidance, so it's slightly below a 5.

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