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

Annotations already declare destructiveHint=true, idempotentHint=true, and readOnlyHint=false, so the safety profile is covered. The description adds real value beyond that by disclosing the state precondition (unpaid only), though it never says whether a cancelled order can be restored or what happens to a paid order if attempted.

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 short sentences, zero filler, with the positive definition of the operation front-loaded and the restriction immediately after. Every clause carries actionable information.

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?

It is a simple two-parameter mutation with full schema coverage, rich annotations, and no output schema, so all that is genuinely needed is purpose plus the eligibility rule. Both are present, and nothing else would change how an agent invokes it.

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 100% and both required parameters (order_id, order_token) are documented in the schema as values returned by create_order. The description adds no parameter-level meaning such as where tokens expire or whether they are reusable, so baseline 3 applies.

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 specific verb (cancel) and resource (order) plus the qualifying state (unpaid), which is enough to tell it apart from create_order/get_order without opening a schema. It stops short of naming any sibling explicitly, so it lands just below the top mark.

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?

"Do not cancel after the payment was sent" gives an explicit when-not condition tied to order state, which is the key routing decision for this tool. No alternative tool is named, but there is no competing cancel path among the siblings, so the guidance is effectively complete.

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