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

Annotations already declare readOnlyHint=true and openWorldHint=false, so the safe-read nature is covered. The description adds useful context about what the caller receives (a link with QR code plus platform-specific install steps), but says nothing about access control beyond ownership of order_id/email, expiry, or failure modes.

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 sentences, front-loaded with the outcome, no filler. Minor redundancy: 'Requires order_id and email' repeats the schema's required list.

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?

No output schema exists, so the description carries the return-value burden, and it does describe the payload (order page link with QR code and install steps). It is nearly complete for a simple read tool; only error/expiry behavior is unaddressed.

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 100% and both parameters are documented in the schema, so baseline is 3. The description restates that order_id and email are required but adds no format, lookup, or validation nuance 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?

States a concrete outcome: a link to the order page containing the QR code and step-by-step eSIM install instructions for both iPhone and Android. An agent can distinguish this from order_status (status lookup) and create_order (creates the order). It doesn't explicitly contrast itself with those siblings, keeping it short of a 5.

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?

'After payment' gives a clear temporal precondition that implies post-purchase context, but no sibling is named and no explicit when-not guidance is given. The agent must infer that order_status or create_order are the wrong picks for this task.

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