set_payment_method

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

No annotations are provided, so the description carries the full disclosure burden. It usefully states the change persists and defines the empty-string revert behavior, but omits auth requirements, what happens to in-flight orders, and error behavior for invalid ids. For a mutation tool with zero annotation coverage this is only partially sufficient.

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 short sentences, front-loaded with the effect and then the parameter sourcing and fallback. Every clause carries information; nothing is redundant with the schema or name.

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?

An output schema exists, so return values need not be described. For a single-parameter setter the description covers effect, source of the value, and the revert case; only edge-case/error behavior and permission requirements are absent, which is a minor gap.

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 0%, so the description must compensate, and it largely does: it explains that card_id should be an id from list_payment_methods and that an empty string has special revert semantics. It stops short of stating id format or validation rules, but the single parameter's meaning is clear.

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?

States a specific verb ('Choose which saved card orders will charge') and resource (the payment method used for charging), with the persistence note clarifying the durable effect. It also names the sibling list_payment_methods as the source of valid ids, so an agent can distinguish it from the listing tool without opening either schema.

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?

Gives clear operational context: use an id obtained from list_payment_methods, and pass an empty string to revert to the account default. That covers the primary and fallback invocation paths, but there is no explicit when-not guidance or mention of prerequisites such as being in a checkout flow.

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