Card transaction details

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

Annotations already declare readOnlyHint, idempotentHint, destructiveHint=false and openWorldHint, so the safety profile is covered by structured data. The description adds behavioral context by restricting applicability to card payments (Mastercard), signalling it is not useful for non-card transactions, but omits what happens if the feed item is not a card payment.

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?

A single, front-loaded sentence with the most relevant scoping qualifier ('For card payments') first and no redundant padding. It is a fragment without an explicit verb, but it wastes no words.

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 no output schema, the description usefully enumerates the kind of values returned (merchant identifier, MCC, POS time, authorisation code, last 4 digits), which partially compensates. It still omits error/empty cases and how the feedItemUid is obtained, leaving gaps for a lookup tool.

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 baseline is 3: accountUid, categoryUid and feedItemUid are all documented in the schema itself, including defaulting behavior. The description adds no parameter meaning beyond the schema.

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 identifies a specific resource and scope: card-payment (Mastercard) transaction details, which implicitly separates it from the generic 'get_transaction' sibling. However, it is written as a noun phrase listing fields rather than a verb+resource statement, so the action ('retrieve details for a card transaction') must be inferred from the tool name.

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?

There is no guidance on when to use this tool versus siblings such as get_transaction or list_transactions, and no prerequisites or conditions are stated. The only hint is 'For card payments', which is a scope qualifier rather than usage guidance.

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