hangup_call

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

With no annotations, the description fully bears the burden of behavioral disclosure. It clearly conveys the abrupt, irreversible effect: 'no graceful goodbye; the call just ends' and 'the caller hears the line drop.' It also states a precondition: 'Only works on calls that are currently in progress.'

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?

Well-structured with a front-loaded summary, then behavioral detail, then usage guidance. Every sentence earns its place—the line-drop analogy, the prerequisite, the sparing-use warning—with no redundancy or filler.

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 single-parameter tool with an output schema present, the description thoroughly covers purpose, prerequisites, usage context, behavioral effects, and alternatives. It is complete and standalone.

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 input schema provides only 'call_id' (string) with no description (0% coverage). The description compensates richly by explaining where the call_id comes from and its validity requirement: 'Use get_active_calls first to find the call_id of a live call.'

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: 'Immediately terminate an active voice session.' It elaborates with specific behavioral detail ('Disconnects all participants instantly', 'the call just ends') and distinguishes from sibling tools by noting it only works on calls currently in progress.

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?

Explicitly states when to use the tool: 'for emergencies, stuck calls, or when explicitly asked to end a call.' It also provides the alternative path: 'In most cases, the agent's own timeout and hangup logic will end calls naturally.' The prerequisite is clear: 'Use get_active_calls first to find the call_id of a live call.'

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