list_payment_methods

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

The description adds value beyond the readOnlyHint annotation by stating that an empty array is returned if no payment methods are saved. This provides expected behavior. No other behavioral traits (e.g., rate limits, auth) are mentioned, but the annotation already covers read-only nature.

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, well-structured sentence that immediately communicates the tool's purpose. There is no extraneous information, and every word 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 simple read-only list tool with a single optional parameter and no output schema, the description is fully adequate. It explains the return case (empty array) and the parameter is well documented in the schema. No gaps remain.

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 input schema has 100% description coverage for the single parameter 'origin', including its meaning and optionality. The tool description does not add any additional clarification about parameters beyond what the schema provides, so baseline score of 3 is appropriate.

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 action 'List', the resource 'payment methods', and the scope 'for your client account with a vendor'. It distinguishes itself from sibling tools which deal with workspaces, invoices, contracts, etc., and none overlap with payment methods.

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 implies the tool is for retrieving saved payment methods but does not provide explicit guidance on when to use it over alternatives, nor does it mention prerequisites or exclusions. However, the context makes it fairly clear.

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