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

Annotations only declare this is not a read-only operation; the description goes well beyond that by disclosing the 24-hour lock window, the race condition ('第一個成功的買家取得商品'), the returned data, and the reversal path via deal_action. It leaves out whether funds/commitment are involved and how the idempotency key interacts with the lock.

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?

Three short sentences, front-loaded with the core action and duration, then the outcome, then the failure/recovery route. Every sentence carries distinct information with no padding.

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 mutating tool with no output schema, the description covers the effect, its duration, the return content, and the undo path, which is what an agent needs before committing. Missing only the cost/commitment side of the transaction and any rate or concurrency retry guidance tied to idempotency_key.

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 75%, with api_key, contact, and idempotency_key already documented in the schema and listing_id self-evident. The description adds no parameter-level meaning (e.g. that contact is shown to the seller only after a successful lock), so it only matches, not exceeds, the schema baseline.

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+resource ('以開價立刻鎖定商品 24 小時') and the outcome ('回傳交易與賣家聯絡方式'), which is clearly distinct from negotiation siblings like make_offer/counter_offer because it executes at the asking price. It does not explicitly name those siblings, so differentiation is implicit rather than stated.

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 clear context for use: immediate purchase at the asking price with first-come-first-served semantics, and routes the agent to deal_action for undoing a mis-lock. It stops short of explicitly stating when NOT to use it (e.g. use make_offer when you want to negotiate a lower price).

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