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

With no annotations provided, the description carries the full burden and discloses a concrete rate limit of 3 requests per minute, plus the requirement that a session must exist before the call succeeds. This gives an agent useful behavioral expectations, though it does not mention side effects or return behavior.

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 three short sentences with no filler: the action is front-loaded, then the rate limit, then the access instructions. Each sentence earns its place and is easy to parse quickly.

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 resend tool, the description covers the core action, the rate limit, and the required authentication flow. The main gap is not explaining how it differs from the many sibling verification/resend tools, which is a minor completeness issue.

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%, with both 'id' and 'email_prefix' already described in the input schema. The description adds no parameter-specific meaning, so the baseline of 3 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?

The description clearly identifies the action ('Resend the domain verification email') and the resource it operates on. It does not explicitly differentiate from sibling tools like resend_verification or resend_email_otp, but the domain-verification-email target makes the purpose clear enough.

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 explicit access prerequisites and an authentication flow: the caller needs a Proof account, must authenticate the client, or use start_login to open a session and then retry. It does not name alternatives or state when not to use this tool, so it stops short of full sibling routing.

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