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

This description provides critical domain knowledge far beyond the structured annotations. It details complex business logic such as plan specificities ('validity starts at installation', 'Europe number is French +33') and financial prerequisites (the user must send 'exactly that amount').

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 dense and runs together without clear formatting or separation. Although it contains immense value, presenting the function, business rules, and multi-step workflow in one continuous, unstructured paragraph makes it difficult for an agent to parse the distinct sections.

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?

The definition is exceptionally complete. It not only details the creation process but also defines the financial obligations, the expected outputs (order_id, token, amount, address), and the necessary subsequent steps (polling, cancellation), making it highly robust.

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?

Since the input schema coverage is 100%, the schema already dictates the semantics of all 6 parameters. The description adds context regarding the business nature of the parameters (e.g., 'coin' and 'plan_id') but does not provide clarifying meaning beyond the schema's own definitions.

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 clearly and specifically states the tool's function: 'Create a crypto invoice for one new eSIM.' It clearly defines the resource being acted upon (eSIM/crypto invoice) and distinguishes it from other sibling tools like get_order.

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 provides comprehensive usage guidelines that cover the entire customer lifecycle. It explicitly details the necessary pre-call confirmation steps and outlines the required follow-up workflow, directing the agent to use 'get_order' for polling and 'cancel_order' for cleanup.

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