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

With no annotations supplied, the description carries the disclosure burden and does add real context: the denomination (1 credit = $0.01) and the two settlement rails (USDC on Base via claim_payment, or x402). "List" also signals a non-mutating read. It does not disclose output shape or whether prices vary by service, which keeps it below a 5.

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, front-loaded with the purpose, then the unit conversion, then the actionable next step. Every sentence carries information an agent needs and nothing is repeated from structured fields.

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 zero-parameter list tool with no output schema, the description needs to convey what comes back and how the values are denominated; it does both via the credit-to-dollar rate. The only omission is a hint at output structure (e.g. per-service price tiers), which is minor here.

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 tool takes zero parameters, so there is nothing for the description to clarify; the baseline for a parameterless tool applies. The schema is an empty object and the description correctly implies no inputs are needed.

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 first sentence pairs a specific verb ("List") with a specific resource ("credit prices"), so an agent knows immediately what the tool returns. It does not explicitly name a contrasting sibling, but no sibling in the list overlaps with pricing, so disambiguation is not really at stake.

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 routes the agent onward: topping up requires get_payment_info followed by claim_payment, or the x402 rail. That gives clear follow-up context and names the alternatives for the payment step. It stops short of stating when *not* to call list_pricing (e.g. use get_balance for existing credit), leaving a small gap.

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