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

Annotations declare non-readonly, open-world, non-idempotent, non-destructive; the description adds richer context: the 0.5 USDC/Base x402 payment, that the calling agent's own wallet pays, and that the server never holds a wallet or pays on the agent's behalf. This goes well beyond the annotations.

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?

Front-loads the paid nature, price and what you get, then the flow. Dense but every sentence carries needed information; slight repetition of the wallet/payment framing costs a point.

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 single-optional-param payment tool with no output schema, the description covers the price, what the token grants, the redemption path, and the full two-call interaction, leaving no operational 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 100% and the single payment_header parameter is fully documented in the schema, including how to obtain and format it. The description reinforces the flow but adds little parameter meaning the schema does not already carry, so the baseline 3 applies.

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 action (buy a prepaid bundle of 100 sanctions_delta calls) with price and mechanism up front. Clearly distinguishes this purchase tool from the redemption sibling it names.

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?

Explicitly routes the agent: redeem with bundle_redeem_sanctions_delta, and call with no payment_header first to receive the x402 challenge, then repeat with the signed header. When-to-use and the two-step flow are spelled out.

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