refund_external_transaction

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

No annotations are provided, so the description carries the full burden of behavioral disclosure. It merely restates the tool's function without revealing whether refunds are irreversible, whether partial/full refunds behave differently, what transaction states are required, or any permission/impact details.

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 a single, front-loaded sentence with no wasted words. It is appropriately brief, though it leans toward under-specification rather than true conciseness that earns high marks.

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?

Despite having an output schema and a detailed input schema, the description is too thin to fully orient an agent: it lacks usage alternatives, behavioral caveats, and any indication of refund state or side effects. Given the large sibling-tool set, this minimal description is insufficient for confident tool selection.

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%, and the schema already documents package_name, external_transaction_id, and the refund body with an example. The tool description adds no parameter-level meaning beyond what the schema provides, so the baseline score of 3 applies.

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 ('Refund') and a specific resource ('external (alternative billing) transaction'), clearly identifying the tool's function. This also distinguishes it from sibling tools like refund_order and cancel_subscription_purchase by explicitly scoping to external/alternative billing transactions.

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 phrase 'external (alternative billing) transaction' implies when this tool is relevant, but the description gives no explicit guidance on when to prefer it over refund_order or cancel_subscription_purchase. There are no stated exclusions, prerequisites, or alternative tool references.

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