buy_number

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

No annotations are provided, so the description must carry the full behavioral burden. It only says 'buy' but does not disclose side effects (cost, billing, irreversibility), post-purchase actions (how the number is delivered), or any limitations (e.g., region availability, phone type restrictions). This is a significant gap for a transactional tool.

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?

A single, grammatically complete sentence that front-loads the core action and the key parameter (region). There is no wordiness or redundancy; it is as concise as possible while still being informative.

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 purchase operation with no output schema and no annotations, the description is insufficient. It does not explain what happens after purchase (e.g., does it return a number ID?), whether there are costs or confirmation steps, or how region/type constraints are validated. An agent would lack critical information to correctly invoke and interpret the result.

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% — both parameters have descriptions ('Тип номера' and 'Регион'). The tool description adds no additional parameter-specific context, so it meets the baseline but does not enhance understanding beyond the schema.

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 states a clear verb ('buy'), a specific resource ('new phone number'), and the target region, making it unambiguous. It is distinct from all sibling tools (send_sms, get_sms_status, etc.) which deal with communication, not number acquisition.

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 implies when to use it (when buying a number), but it does not explicitly contrast it with alternatives or mention any prerequisites (e.g., account balance, availability checks). No mention of when NOT to use it, so it leaves some inference to the agent.

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