send_sms

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

No annotations are provided, so the description carries the full burden. It only states that the tool sends SMS requires an API key. It fails to disclose critical behaviors such as whether the operation is destructive, rate limits, idempotency, or what happens on failure.

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 a single sentence with no waste, directly stating the endpoint and action. It is appropriately concise, though it could benefit from slightly more detail without becoming verbose.

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 tool involves nested objects, required headers, and bulk operations, which are complex. The description is too brief to cover return values, error handling, or how to properly construct requests. It leaves significant gaps for an AI agent.

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 high (75%+), so the baseline is 3. The description adds only the requirement for X-API-VASKEY; it does not explain the meaning of 'type: 1' or the structure of 'messages' beyond what the schema already provides.

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 tool sends SMS messages (bulk or single) and identifies the resource. It distinguishes the basic action from the sibling send_sms_get (which likely retrieves messages). However, it does not explicitly differentiate from other SMS-sending tools that may exist.

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 mentions a requirement (X-API-VASKEY) but provides no guidance on when to use this tool over alternatives like send_sms_get or when not to use it. No usage context or exclusions are given.

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