Verify a customer's OTP code by phone number and 6-digit code, returning whether it is valid.
Check an OTP code the customer received. Returns whether the code is valid.
| Name | Required | Description | Default |
|---|---|---|---|
| phone | Yes | Phone number in international format without + (e.g. 6281234567890) — the number the OTP was sent to | |
| otp_code | Yes | The 6 digit code the customer entered |
Changes observed during successful MCP inspections.
v1.1.0Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
With no annotations, the description carries the burden of disclosing behavior. It only states the return value and says nothing about whether verification consumes/invalidates the code, whether it is idempotent, or what happens on failure. This is a meaningful gap for an OTP check.
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 short sentences with no filler; the primary action is front-loaded and the return behavior is stated immediately. 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?
For a simple two-parameter tool with no output schema, the description states the essential purpose and return value. However, it omits side-effect and error behavior, which matters because an OTP verification may alter the code's state and the tool has no annotations to cover 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%, and both parameters are already documented with format and meaning (phone without '+', 6-digit code). The description adds no parameter-specific detail, so it meets the baseline but does not exceed the schema.
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 names a specific action ('Check an OTP code') and a concrete resource (the code the customer received), and clarifies the outcome ('Returns whether the code is valid'). It is clearly distinct from send_otp and send_message siblings, though it does not explicitly name an alternative.
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 phrase 'the customer received' implies this tool is for verifying an OTP after it has been delivered, but there is no explicit guidance on when to prefer it over send_otp or when not to use it. Its use context is inferable rather than stated.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.