send_viber_message

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

With no annotations provided, the description carries the full burden of behavioral disclosure. It only states that it sends a message, without revealing any side effects, authentication requirements, delivery guarantees, or error behavior. The agent has no information about what happens on failure, whether the operation is asynchronous, or if any fees apply. This is a severe gap.

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 a single short sentence, which is not verbose, but it is under-specified. It lacks structure and front-loaded details. Rather than being efficiently concise, it omits essential context, making it merely brief rather than well-crafted.

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 tool that sends a message, the description is incomplete. It does not explain what happens on success (return value), how errors are conveyed, or any constraints on the recipient number or text length. The schema covers parameters, but the description fails to address the tool's overall behavior beyond the action itself.

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?

The schema provides descriptions for both parameters ('to' and 'text') with 100% coverage, so the baseline is 3. The description itself adds no parameter-specific meaning beyond what the schema already states. It does not offer format hints, examples, or clarifications, but the schema is sufficient.

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 'Отправить сообщение через Viber.' is a direct translation of the tool name 'send_viber_message'. It restates the name without adding any specificity about the message content, delivery, or scope. While it does distinguish the channel (Viber), it's essentially a tautology, providing no additional clarity beyond what the name already conveys.

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 gives no guidance on when to use this tool versus alternatives like send_sms or make_call. There is no mention of prerequisites, scenarios, or exclusions. An agent would have to infer that this is only for Viber messages, but no explicit usage context is provided.

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