start_assistant_call

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

With no annotations, the description carries the full burden for behavioral disclosure. It only states the basic action and a constraint on from_ (must be a Telnyx number), but does not mention side effects, prerequisites, whether the call is asynchronous, or what happens on failure. This is minimal transparency.

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 and well-structured with a summary line, parameter list, and return type. Every sentence adds value, with no redundant or fluff 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?

The description covers the parameters and return type but lacks preconditions (e.g., assistant must exist) and post-conditions (e.g., how to interpret the response). Given no annotations and no output schema, it is somewhat incomplete, though the core purpose is clear.

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 schema provides only titles ('To', 'From', 'Assistant Id'), so the description is essential. It adds meaning by explaining each parameter's role, including the requirement for from_ to be a number on the Telnyx account. While concise, it compensates well for the 0% schema coverage.

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 ('Start a call') and the specific context ('using an AI Assistant with a phone number'), which distinguishes it from generic call tools like make_call. The verb 'start' and resource 'assistant call' are explicit.

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 implies the use case (calls involving an AI assistant) but does not explicitly state when to prefer this tool over make_call or other call-related siblings. It lacks any mention of alternatives, exclusions, or when not to use it.

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