otp_send_sms

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

Annotations indicate readOnlyHint=false and destructiveHint=false, confirming a write operation. The description adds behavior beyond annotations: the mandatory placeholder, failure condition (422 error), and parameter defaults (expiry=5, length=4). No contradictions.

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 repeats schema parameter descriptions, making it longer than necessary. It front-loads the critical requirement, but the Python docstring style (e.g., ':param ...') adds redundancy. Could be more concise.

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?

Given the tool's complexity (OTP sending), annotations, and the presence of an output schema (not shown), the description covers the core functionality, failure mode, and parameter details. It does not describe the return value, but the output schema likely does that.

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 100%, so baseline is 3. The description adds extra value by emphasizing the critical nature of <%otp_code%> in the message parameter, which is not highlighted in the schema description.

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 'Send' and the resource 'OTP via SMS'. It distinguishes from sibling tools like otp_send_email and otp_verify_sms by specifying the channel and the critical placeholder requirement.

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 provides a critical guideline: the message must contain <%otp_code%> or the call fails with 422. It does not explicitly compare to alternatives (e.g., otp_send_email), but the name and context imply the use case for SMS OTP delivery.

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