nex_ip_buy

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

Annotations already flag destructiveHint=true and idempotentHint=false, and the description builds on that by explaining the actual mechanics: asynchronous delivery, balance charged at the current server price, and a reconciliation-before-retry rule. This is exactly the kind of non-obvious operational context that prevents an agent from double-charging the account.

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?

Leads with the action, then delivery semantics, then billing, then retry safety — a sensible order with no filler. It is dense but every sentence carries operational weight; only the trailing attempt cap could be tightened.

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?

Behavioral coverage is strong and the async follow-up path is spelled out, which compensates for having no output schema. However, a purchase tool with three required, largely undocumented parameters should say what productId refers to or how to discover valid values, and the description is silent on that.

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 only 33% — duration is documented, but productId and quantity carry no description anywhere. The tool description never mentions any of the three required parameters, so an agent gets no help on which productId values are valid or how quantity interacts with duration, despite all three being mandatory.

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 ("Buy general proxies") and immediately qualifies the product line, which separates it from the sibling purchase tools nex_ip_snap_buy, nex_sms_buy, nex_mail_buy and nex_captcha_buy. It doesn't name those siblings explicitly, so the differentiation is left partly implicit, but the scope is unambiguous.

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 ("call it directly when the user's task needs it"), an explicit when-not ("a price inquiry is not a purchase request"), and the follow-up path (check nex_ip_order_list and nex_proxy_list). It also forbids a specific failure mode ("never repeat a pending order") and caps retries at 3 per resource flow.

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