start_add_email

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

With no annotations present, the description carries the full burden and does a solid job: it discloses the side effect of sending an OTP, states the return of a session ID, and surfaces the prerequisite that a Proof account and session or API key are needed. It does not describe every edge behavior, such as expiration or duplicate handling, but it covers the key observable behavior well.

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 core purpose, the second covers side effects and return value, and the third provides necessary access context. Every sentence earns its place, and there is no redundant filler.

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 single-parameter initiation tool with no output schema, the description is complete: it explains what the tool does, what it sends, what it returns, and what access is needed. The hint to verify with the returned session ID contextualizes the next step without requiring an exhaustive sibling comparison.

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 100%, and the schema already describes 'email' as an email-formatted string used to add an email address. The description adds a little extra context by noting the OTP is sent to that email, but this is not a major semantic expansion beyond 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 uses a specific verb phrase, 'Start adding a new email address,' names the immediate action ('Sends an OTP code to the email'), and the outcome ('Returns a session ID to verify with'). This clearly distinguishes it from sibling tools like verify_email_otp, resend_email_otp, get_add_email_status, and remove_email.

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 gives clear context for when to call this tool: initiating the addition of an email address that will be verified by OTP. It also includes important access guidance, noting that a Proof account is required and explaining how to authenticate via PROOF_API_KEY or start_login before calling. It does not explicitly name sibling alternatives or state when not to use it, so it falls short of a 5.

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