make_call

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

Annotations only supply openWorldHint=true, so the description carries the behavioral load and does it well: it discloses that the conversation is driven by the caller's webhook, and that every call opens with an automated-assistant disclosure added server-side and not removable. The latter is non-obvious, non-configurable behavior an agent must know before calling. It stops short of describing failure modes or call outcome.

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?

Two tight sentences, zero filler. The core action leads, and the prerequisite/disclosure constraints follow in a scannable second paragraph.

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 call-initiation tool with no output schema and fully documented parameters, the description covers action, prerequisites, and a mandatory behavioral quirk. The remaining gap is that it never points to make_conversation_call as the alternative, which matters given how similar the two siblings are.

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 description coverage is 100%, so all five parameters are already documented, making 3 the baseline. The description adds one meaningful nuance: the opening disclosure is server-side and cannot be removed, which implicitly constrains what initial_greeting can control, but it does not explain voice override or from_number_id selection.

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?

States a specific verb and resource ('Initiate an outbound ... phone call') and adds the defining mechanism: webhook-driven, with the caller's backend handling conversation logic. That mechanism implicitly separates it from make_conversation_call, but the sibling is never named, so the differentiation requires inference.

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 gives a real precondition ('The agent must have a phone number attached and a webhook configured'), which tells the agent when the call can succeed. However, it never states when to pick this over make_conversation_call or what happens if the webhook is missing, leaving the routing decision to inference.

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