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

Beyond the annotations, the description discloses the billing model (per-GB, no data package), that installation happens later, and that idempotency_key changes repeat behavior. These are meaningful operational details for a mutation tool. The keyed idempotency note does not contradict idempotentHint=false; it clarifies a conditional exception.

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 four short sentences with no filler. The core action is front-loaded, followed by only operationally relevant notes about billing, installation timing, and keyed idempotency.

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 description covers key behavior for a mutation tool without annotations, including billing and installation timing. However, it omits the required country parameter semantics and does not clarify what the returned order/profile contains, despite having no 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 0%, so the description must carry parameter meaning. It explains idempotency_key well, but the required country parameter is never described in the schema or the description. Half of the parameters remain semantically unexplained.

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: 'Creates an eSIM profile.' This clearly distinguishes it from read-only siblings like get_usage or esim_install_steps. It does not explicitly contrast with quote_esim, but the action is still clear.

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?

There is no guidance on when to call order_esim versus quote_esim, prepare_order, or order_service. The billing note ('Data is billed per GB as it is used. There is no data package.') describes consequences, not selection criteria.

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