Buy Virtual Number

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

The description adds value beyond annotations by stating it returns order_id and phone_number, indicating mutation ('purchase'). Annotations already show readOnlyHint=false, destructiveHint=false, idempotentHint=false. The description could disclose potential costs or failure conditions but does not.

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 sentences with no wasted words. The first sentence states purpose and output; the second gives actionable next steps. Front-loaded and efficient.

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?

The description explains the tool's purpose, output, and follow-up actions. Given no output schema, it adequately conveys return values. It lacks mention of pricing or potential failures, but for a straightforward purchase tool with two required params, it is mostly complete.

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 the baseline is 3. The description provides example service codes ('telegram', 'whatsapp', 'google') and country codes ('US', 'GB', 'RU'), but these are illustrative and already implied in the schema. No new parameter meaning is added.

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?

The description clearly states 'Purchase a virtual phone number for SMS verification', specifying the verb and resource. It also mentions the output (order_id and phone_number), distinguishing it from sibling tools like virtualsms_get_order or virtualsms_find_cheapest.

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?

The description provides post-purchase guidance by suggesting check_sms or wait_for_sms for verification. However, it lacks explicit when-to-use guidance versus alternatives like virtualsms_get_order or virtualsms_find_cheapest. It gives clear context for next steps but no exclusions.

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