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

Annotations only cover the safety profile (not read-only, not destructive), so the description carries the extra burden and does add value: it discloses the required orderId precondition, the refusal behavior when it is missing, and the effect (stops expiring, becomes receipt-findable). Idempotency and return behavior are still unstated, keeping it below 5.

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?

Front-loaded with the core action and effect, then the requirement and rationale. The closing rationale ('a confirmed booking nobody can find on a receipt is worse than an expired hold') is colorful but does justify why orderId is mandatory, so it earns its place; slightly verbose overall.

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 2-param mutation with no output schema, the description covers purpose, precondition, and error behavior, and annotations cover the safety profile. It is nearly complete, missing only idempotency and what the confirmed result returns.

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%, so both parameters are already documented, and the description largely restates them ('the order the booking was sold on'). Baseline 3 is appropriate since the schema does the heavy lifting and the description adds little new syntax or format detail.

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 precise verb and resource plus the state transition ('turn a hold into a real booking'), which cleanly separates it from hub_hold_booking (creates the hold) and hub_cancel_booking (kills it). An agent can identify the operation without opening the schema.

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?

Gives a clear triggering condition ('once the order behind it is paid') and a hard precondition (orderId required, refused without it). It does not explicitly name the sibling alternatives (hold/cancel) or state when to prefer them, so it stops short of full routing guidance.

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