List Vapi Calls

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

With no annotations provided, the description carries full burden for behavioral disclosure. It mentions the tool returns call IDs, status, cost, and basic info, but lacks critical details like whether this is a read-only operation, pagination behavior, rate limits, authentication requirements, or error handling. For a list tool with 5 parameters, this is insufficient.

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 brief (two sentences) and front-loaded with the core purpose. Every sentence contributes: the first states the action and filtering capability, the second specifies return values. No wasted words, though it could be slightly more structured with bullet points for return fields.

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?

Given the tool has 5 parameters, no annotations, and no output schema, the description is incomplete. It lacks behavioral context (e.g., read-only nature, pagination), doesn't explain the return structure beyond high-level fields, and provides no usage guidelines. For a list tool with filtering capabilities, this leaves significant gaps for an AI agent.

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 description mentions 'optional filters' which aligns with the 5 parameters in the schema, but adds no specific meaning beyond what the schema already provides (schema description coverage is 100%). The baseline score of 3 is appropriate since the schema fully documents parameters, though the description doesn't compensate with additional context like filter combinations or examples.

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 the action ('List calls') and resource ('calls'), and mentions optional filtering. However, it doesn't explicitly differentiate from sibling tools like 'vapi_get_call' (singular retrieval) or 'vapi_list_assistants' (different resource type), which would be needed for a perfect score.

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 no guidance on when to use this tool versus alternatives. It doesn't mention when to choose 'vapi_list_calls' over 'vapi_get_call' for a specific call, or when to use it versus other list tools like 'vapi_list_assistants'. No exclusions or prerequisites are stated.

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