Place an outbound call (click-to-call)

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

Annotations cover the safety profile, but the description adds real context: the required pbx:write permission, the ring-then-bridge side effect, and the returned { callId, status } that must be retained for transfer/hangup. It doesn't cover failure behavior, rate limits, or billing implications of placing a real call, so not a 5.

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?

Front-loaded with endpoint and permission, then mode semantics, then return value — a sensible priority order with no filler. The telegraphic fragment style is dense but slightly harder to parse than full sentences.

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?

With no output schema, the description correctly supplies the return shape and the lifecycle implication (keep callId). For a non-idempotent, open-world mutation tool it's nearly complete; error/partial-failure behavior is the remaining gap.

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 75%, and the description compensates for the main gap by giving per-value meaning to the connectTo.type enum (extension vs. queue vs. ivr call flows), which the schema lists without explanation. It adds the interaction between `to` and the mode rather than repeating field descriptions.

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 names a specific verb and resource (POST /v1/calls) and clarifies that this initiates an outbound/click-to-call, which separates it from hangup_call and transfer_call siblings. It never explicitly says 'use this instead of X', but the callId handoff sentence implies the ordering in the lifecycle.

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?

It clearly explains the three connectTo.type modes and what each does (agent-first bridging vs. direct dial to queue or IVR), which is the main usage decision for this tool. It lacks explicit 'when not to use' guidance or a named alternative for other call flows.

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