Get payment accounts

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

Annotations already establish the read-only, idempotent, non-destructive nature of the operation. The description adds meaningful behavioral detail: results are masked and never include full numbers, and the tool wraps two specific account-retrieval methods. This goes beyond what annotations alone provide.

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?

Three short sentences each earn their place: the first defines the output shape, the second states the masking guarantee, and the third gives implementation and usage context. There is no filler or redundancy.

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 one-parameter read-only lookup, the description fully equips an agent: it states what is returned, the masked fields, the underlying wrappers, and when the tool is useful. The lack of an output schema is mitigated because the description enumerates the returned fields.

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 has only client_id with no description, and the description refers to it only indirectly as 'a client has on file.' Because there is one self-explanatory required parameter, the gap is small, but the description does not explicitly define the parameter or its expected meaning.

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 identifies what is returned ('Cards and bank accounts a client has on file'), enumerates the masked fields, and distinguishes this tool from siblings focused on invoices, transactions, or services. It also names the underlying wrapped methods, leaving no ambiguity about the resource and operation.

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 description provides concrete use cases ('useful for autodebit failures and expired cards') that tell an agent when this tool is appropriate. It does not explicitly state when not to use it or name alternatives, but the intended context is clear.

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