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

With no annotations, the description carries full behavioral burden. It adds one useful trait—"Large payments settle instantly"—but omits critical context for a payment mutation: irreversibility, authentication/OTP requirements beyond the schema note, idempotency behavior, limits, and failure handling.

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 tightly written sentences with no wasted words. Purpose is front-loaded, and the settlement-speed note is compact and relevant.

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 six-parameter payment mutation with no annotations and no output schema, the description is far too thin. It lacks prerequisites, safety warnings, idempotency guidance, authentication details, and any information about what the call returns.

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 coverage is only 17%, with just the otp parameter described in the schema. The description does not explain from_account_id, amount format, payee_id versus external wallet address, idempotency_key, or description, leaving most parameters undocumented.

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 uses a specific verb, "Pay", and a clear resource scope: an existing payee or external wallet address. The word "existing" helps distinguish it from add_payee, though it does not explicitly name that sibling.

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?

It implies this is for payments to an existing payee, but gives no explicit when-to-use guidance or comparison to alternatives such as add_payee or list_payees. An agent must infer that add_payee is for creating payees rather than paying them.

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