schedule_sms

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

With no annotations, the description must carry the behavioral burden. It discloses the required parameters and the 500-recipient cap, but does not mention the return value, whether scheduling is asynchronous, idempotency behavior, or error handling. For a mutation tool, this is a moderate gap but not misleading.

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 sentences with no fluff. The first sentence states the purpose and endpoint, and the second states the requirements and limit. Information is front-loaded and every word earns its place.

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 essential calling contract but omits the response format (e.g., scheduled message ID) and any post-scheduling behavior. Given the tool has no output schema, mentioning the return value would be valuable. It also does not clarify whether the call is synchronous or asynchronous, which is relevant for scheduling.

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 covers all 7 parameters, but the description adds critical semantics: the either/or requirement for to and list_uuid, and the recipient cap. These are not fully captured by the schema's structure, which lists them as separate optional properties. The description meaningfully clarifies invocation constraints.

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 verb 'Schedule' and the resource 'SMS', and explicitly mentions single or bulk modes. The API endpoint reinforces the action. While it does not name sibling tools, the term 'schedule' and the requirement for a future send_at time distinguish it from immediate-send tools like send_sms.

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 tool is for scheduling future messages, but it does not explicitly state when to use it versus immediate-send siblings like send_sms or bulk_send_sms. There is no explicit exclusion or alternative guidance, leaving the agent to infer the context from the send_at parameter.

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