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

The description goes well beyond the sparse annotations by disclosing a financial side effect (Stripe charge), price re-validation tolerance, order creation, and likely error classes such as SCA, payment-action-required, and declined. This materially informs the agent about real-world consequences and failure modes.

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 tight sentences with no filler. The core action comes first, followed by the critical operational details and likely error outcomes. Every clause adds 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 mutating financial tool with no output schema, the description covers the main behavior, side effects, and error modes well. However, it does not mention what a successful response returns (e.g., an order object or order ID), nor explicitly tie the confirmation_token to a prior confirmation_required response; the schema covers the token but the description could be more self-contained.

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 all parameters are already documented in the schema. The description adds useful behavioral context but does not explain individual parameter semantics or provide extra meaning beyond what the input schema already supplies.

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 states a specific verb and resource ('Confirm a purchase intent') and adds concrete outcomes: price re-validation within 1p tolerance, Stripe Connect destination charging, and order creation. This clearly distinguishes it from sibling tools like purchase_create_intent and purchase_cancel_intent.

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 purpose implies usage after a purchase intent has been created and when the agent is ready to complete the purchase, but it never explicitly states when to use this versus purchase_create_intent or purchase_cancel_intent. There is no when-not-to-use guidance or alternative tool mention, only inferred context.

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