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

Adds non-obvious operational behavior: the call is asynchronous, returns callId immediately, and has a defined set of terminal statuses. This goes beyond the annotations, which only indicate non-readOnly, non-idempotent, and open-world behavior, by explaining the actual call lifecycle.

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?

Three sentences with no filler: purpose, async behavior, and follow-up action are each given their own concise sentence. The most decision-relevant facts are front-loaded.

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?

Covers the full invocation lifecycle from returning callId through terminal statuses, and names the exact sibling tool to use for follow-up. With the rich schema and annotations, nothing essential for selecting or invoking this tool is missing.

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 100%, so the structured descriptions already document all 11 parameters. The description adds minimal parameter-level detail beyond naming the objective and callId, which is acceptable but not additive given the schema already carries that weight.

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 concrete action ('Place'), a specific resource ('outbound AI phone call'), and a purpose ('toward an objective'). It also clearly differentiates from sibling get_call by contrasting placement with polling, and from list_calls/set_appointment by resource and action.

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 explicitly tells the agent to poll get_call with the returned callId until a terminal status, giving a clear post-invocation workflow. It doesn't explicitly state when not to use this tool or compare it to list_calls/set_appointment, but the placement-vs-retrieval distinction is clear from context.

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