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

No annotations at all, so the description carries the full behavioral burden. It discloses the outcome shape ('returns how to complete the purchase') but says nothing about whether the contact info is required for the seller to respond, whether this notifies anyone, whether it is idempotent/repeatable, or what side effects persisting an intent has.

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 compact sentences with the eligibility condition front-loaded and the outcome second. No filler or restatement of the tool name.

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 covers purpose and hints at the return value, which helps given there is no output schema, and the nested contact object is at least partially hinted at by 'how to complete the purchase.' But with a nested 4-field object, zero schema docs, and no annotations, an agent still lacks enough to know how to populate contact/message correctly.

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% across three parameters, including a nested contact object with four fields (email, wallet, discord, telegram). The description never explains which of these matter or why contact is optional when it is arguably the point of recording interest, so it fails to compensate for the schema gap.

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 action (records interest) and scopes it to a precise listing class: peer listings without on-site checkout (partner products, community servers, unpriced domains). This implicitly separates it from create_order, which covers on-site checkout, but it never names that sibling or the resource object itself.

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 explicit when-to-use criteria with concrete examples (partner products, community servers, price-less domains), which is a clear trigger condition. It stops short of naming the alternative tool to use when the listing does have on-site checkout, so the agent must infer that.

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