start_domain_email_verification

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

With no annotations available, the description carries the full burden and does a solid job: it discloses that the tool sends a verification email to an admin address, requires a Proof account, and explains the API-key vs. login fallback flow. It doesn't mention what happens after the code is sent, but the core side effect and authentication behavior are transparent.

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 compact and front-loaded: the first sentence states the action, the second clarifies the effect, and the ACCESS note is separated and directly useful. There is no redundant filler or restated schema information.

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 two parameters, full schema coverage, and no output schema, the description covers the essential operational context: what it does, where the code is sent, and what authentication is needed. It stops short of describing the follow-up confirmation step, but the 'start' semantics and sibling tool names make that inferable.

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 the schema already explains both parameters. The description adds only a general notion of a 'standard admin email address,' which lightly reinforces the email_prefix default but doesn't substantially improve on the enum and descriptions already present.

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 states a specific verb and resource: 'Start domain verification via corporate email.' It further says a verification code is sent to a standard admin email address, which clearly differentiates this from sibling domain-verification tools that use DNS, credentials, or provider connections.

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?

It gives clear context for when to use the tool: when starting domain verification over corporate email. It also provides explicit authentication prerequisites (Proof account, PROOF_API_KEY, or start_login). It does not name alternative tools or state when not to use it, but the contextual guidance is strong enough.

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