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

There are no annotations, so the description carries the burden of explaining behavior. It does disclose the primary state-changing outcome ('receive a session'), but it does not mention session properties, whether a token is returned, failure behavior, or rate-limit/security implications. It is marginally adequate but not transparent about side effects beyond receiving a session.

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, front-loaded sentence with no filler. It directly conveys the essential action and result in eight words, earning its place without redundancy.

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, the description is minimally adequate: it states the purpose and that a session is received. However, it omits the surrounding auth flow context, such as needing to call auth_start first, what a session looks like, and error conditions. These gaps prevent it from being fully context-complete.

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 (email, code) are already documented as 'Login email' and 'Six-digit code'. The description adds no parameter-level meaning beyond what the schema provides, so the baseline score of 3 applies.

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 action (verify an OTP) and the outcome (receive a session), using a specific verb and resource. It is distinct from the related auth_start sibling by implying the verification step, though it does not explicitly name auth_start or other alternatives.

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 no explicit when-to-use guidance or alternatives. It does not say to call this after auth_start, nor does it describe when not to use it. The usage context is only weakly implied by the tool name and 'Verify an OTP' phrasing.

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