send_sms

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

With no annotations provided, the description adds behavioral context such as the paid nature and balance requirement. However, it does not disclose other behaviors like message length limits, delivery confirmation, or authentication needs for optional parameters.

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?

The description is short and front-loaded. Every sentence adds value: first defines the action, then specifies prerequisites. No unnecessary words or repetition.

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?

While output schema exists and may cover return values, the description omits important context such as how authentication works (merchant_login/password1), message encoding, and error scenarios. It somewhat compensates with balance and format info but leaves gaps.

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%, so the description must compensate. It only explains the phone parameter's format. Other parameters like message, merchant_login, password1, and algorithm receive no additional meaning 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 begins with 'Send an SMS via Robokassa's SMS service,' which clearly identifies the verb and resource. It distinguishes itself effectively from sibling tools such as check_payment or create_invoice, as none of them involve SMS sending.

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?

Explicitly states it is a paid feature requiring a non-zero SMS balance and that the phone must be in international format. This guides when to use the tool and under what conditions, though it does not explicitly mention alternatives or when not to use it beyond balance constraints.

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