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

Annotations already establish read-only, idempotent, and open-world behavior. The description adds meaningful context beyond them, especially 'zero custody, no fiat leg' and deterministic template generation, though it does not discuss auth, rate limits, or error behavior.

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 definition is a single dense sentence that front-loads the core transformation and settlement context with no filler. Every phrase, including custody and fiat caveats, contributes useful information.

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?

Given a full output schema, complete parameter descriptions, nested input objects, and annotations covering safety/idempotency, the description provides sufficient context to select and call the tool correctly. Return-value details are appropriately left to the output schema.

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%, so the schema already documents all four parameters, including chain_id default and fallback recipient. The description adds accepted ISO 20022 message types but does not explain parameter roles or interactions beyond the schema.

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 names a specific verb and resource: translating validated ISO 20022 pain.001/pacs.008 instructions into EIP-712 payment-intent templates for x402 settlement. It clearly distinguishes this mapping step from validation by specifying the input is already validated.

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 gives clear context for when to use it: after ISO 20022 validation, when producing x402 Base L2 USDC settlement intents. It does not explicitly name alternatives or exclusions, so it falls short of a full when/when-not routing statement.

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