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

Annotations already signal this is neither read-only nor destructive, so the description does not need to restate mutation. It adds useful behavioral context beyond annotations: the invoice is one-off and the payer must open the returned mini_app_invoice_url. It does not mention webhooks or expiry, but the provided behavior is meaningful.

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 description is extremely compact and front-loads the action, then immediately gives the practical outcome the caller needs to know. The doc reference is a single short tail. Every part earns its place.

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 tool with 15 optional parameters and no output schema, the description only explains the creation action and the returned URL, then defers to documentation. It does not summarize the fiat/crypto modes, open-amount behavior, or which parameter combinations matter most. An agent could call it correctly but may under-specify an invoice without consulting the referenced docs.

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 schema covers 100% of the 15 parameters with individual descriptions, so the description need not repeat them. The tool description itself does not add param-level guidance, which is acceptable given the schema's complete coverage, but it also does nothing extra.

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 states a specific action and resource: "Create a one-off payment invoice". It also names the key output field, result.mini_app_invoice_url, which defines the tool's purpose. The "one-off" qualifier helps distinguish it from subscription-plan creation.

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 "one-off" wording implies a single-payment use case versus subscriptions, and the doc pointer offers an avenue for more detail. However, no alternative tool is named and no explicit when-to-use or when-not-to-use guidance is given, leaving the distinction from siblings like createCheck and createSubscriptionPlan implicit.

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