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

Annotations already declare destructiveHint=true, idempotentHint=true, readOnlyHint=false and openWorldHint=false, so the safety profile is covered. The description adds the useful scope constraint that paid orders are out of band, but says nothing about what the cancellation does to the order, whether it is reversible, or auth requirements.

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, zero filler, with the primary capability stated first and the exception second. Every sentence 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 simple one-parameter mutation with no output schema, the description plus rich annotations cover the essentials: what it does, when it applies, and the alternative path for paid orders. Minor gaps remain about ownership/authorization and what the caller receives on success.

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% for the single parameter, so the description carries some burden. It never mentions order_id, its expected format, or where the caller obtains it; the parameter name is self-explanatory but no added meaning is provided.

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 verb (Cancel) and resource (order) plus a scope condition ('that has not been paid yet'), which lets an agent distinguish it from pay_order and get_order without opening any schema. It stops short of naming siblings explicitly, which is why it is not 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?

It gives a clear when-to-use condition (unpaid orders) and a when-not plus fallback path (paid orders must go through support email before printing). That is actionable routing guidance, though no sibling tool is named as the alternative.

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