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

Beyond the destructiveHint annotation, the description adds a crucial warning that this 'SENDS TO REAL RECIPIENTS' and delivers to the 'resolved recipient set.' This goes well beyond the annotation by emphasizing real-world side effects and that recipient resolution is part of execution, which is exactly the behavioral context an agent needs.

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 compact, front-loads the most important warning, then states the action and endpoint with no wasted words. Every element contributes meaning, and it remains easy to scan.

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 destructive 6-parameter send operation with no output schema, the description provides the essential safety warning and operation clarity. The schema fills in parameter semantics, though the description could have added a bit more about expected outcomes or response behavior; as-is it is sufficient for correct invocation.

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 description itself does not explain any parameters, but the input schema covers 100% of them with meaningful descriptions such as 'Recipient filter object (overrides the broadcast's configured audience)' and 'Skip recipients missing an id instead of erroring.' With full schema coverage, the description does not need to add parameter detail.

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 states a specific action ('Trigger an API-triggered broadcast') on a clear resource ('broadcast'), and the warning 'SENDS TO REAL RECIPIENTS' strongly distinguishes it from the read-only sibling tools. It also names the exact API endpoint, leaving no doubt about what operation this tool performs.

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 makes the use case clear: trigger an API-driven broadcast to a resolved recipient set. It does not explicitly name alternatives or say when not to use it, but the broadcast resource and the sibling 'send_transactional_email' implicitly separate the two sending paths.

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