Send an OTP code

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

Annotations only say readOnlyHint=false and destructiveHint=false; the description adds the crucial cost fact ("This really sends and spends SendKuy credit") and the fallback-through-channels behavior that the annotations cannot express. It also reconciles the idempotentHint=false annotation by explaining that dedupe_key provides conditional, not blanket, idempotency.

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?

Front-loaded with what the tool does and the returned id, then the follow-up and cost warning. The dedupe sentence partially duplicates the schema's dedupe_key text, a small redundancy in an otherwise tight definition.

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?

An output schema exists, so return values need no explanation, and the description still names the vrf_ id shape and the credit cost. It omits that `to` or `email` must be supplied to match the chosen channels, a detail an agent could trip over given zero required parameters.

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 coverage is 75%, so the schema already documents to/email/ttl/channels. The description's dedupe_key sentence largely restates the schema's own extensive dedupe_key description, and it adds no meaning for the undocumented locale and code_length parameters. Baseline 3 for a mostly-covered schema is appropriate.

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?

"Send a one-time code to a phone number or email address and get a verification id (vrf_...)" gives a specific verb, resource and return value. It is clearly separated from the sibling sendkuy_check_verification (a different verb on the same resource) and from the generic sendkuy_send_message by the code-generation framing.

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 routes the next step to sendkuy_check_verification and explains the channel fallback order, which tells the agent how the call behaves. It does not say when to prefer this over sendkuy_send_message for a non-code message, so it stops short of full when/when-not coverage.

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