make_outbound_call

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

Annotations already mark destructive and open world hints. The description adds important context: it makes an API call to ElevenLabs (incurring costs), automatically detects provider type, and specifies the agent and phone number IDs. No contradiction with annotations.

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?

Description is relatively concise with a clear warning front-loaded. It uses a structured list for arguments. A few sentences could be more streamlined, but overall it's efficient without unnecessary content.

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 with 3 required parameters and an output schema, the description covers purpose, parameters, cost warning, and provider detection. It lacks details on error handling or call state, but given the complexity and existing annotations, it is fairly 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 has zero description coverage (0%). The description compensates by explaining each parameter: agent_id (ID of agent), agent_phone_number_id (ID of phone number), to_number (phone number in E.164 format with example). This adds critical 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?

Clearly states the tool makes an outbound call using an ElevenLabs agent. The verb 'Make' and resource 'outbound call' are specific. It distinguishes from sibling tools like text_to_speech by mentioning outbound calling and agent handling.

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?

Includes a cost warning and explicitly says 'Only use when explicitly requested by the user.' This provides clear when-to-use guidance. However, it does not mention alternative tools for related tasks (e.g., receiving calls), which would improve the score.

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