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

With no annotations at all, the description carries the full burden and does well: it discloses the auth requirement, two concrete error responses, and the refund side effect on paid orders. It stops short of saying whether cancellation is reversible or whether the refund is synchronous, which are the remaining operational unknowns for a destructive action.

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 core action and its refund consequence are front-loaded, followed by auth and error behavior. Slightly padded by the '本体: reservation → Action: cancel' ontology line, which an agent does not need to invoke the tool.

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 an unannotated, output-schema-less mutation tool, the description covers auth, error codes, parameter provenance, and the refund consequence. Missing only reversibility/idempotency and refund timing, which are secondary.

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 single parameter is undocumented in the schema. The description compensates by explaining that reservationId is the serviceid returned by reservation.book, which is exactly the provenance an agent needs to populate it correctly.

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 and resource ('取消预约：按预约号取消') and adds a material side effect ('已支付订单会同时发起退款'). It ties the input to a sibling ('预约号取自 reservation.book 返回的 serviceid'), which implicitly separates it from reservation_modify, though it never names that alternative explicitly.

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 clear preconditions — a login token or a user-bound cloud-market instance — plus the specific failure modes (401, code=40003 with data.bindUrl). That is useful context but it is authentication guidance, not a when-to-use/when-not-to-use rule against reservation_modify, and no alternative is named.

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