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

Annotations only declare that this is a non-read-only, non-destructive, non-idempotent, open-world call. The description goes well beyond that by disclosing the two-step verification flow, that a code is dispatched to the address, that the API key is unchanged, and the account-recovery/payout stakes. It does not cover failure cases or re-request behavior for a non-idempotent operation.

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?

Three compact sentences with no filler, and the crucial follow-up tool is named early. The auth requirement is front-loaded at the expense of the operation statement, which is a minor ordering weakness rather than a verbosity problem.

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 one-parameter tool with no output schema, the description supplies the surrounding workflow, the downstream confirmation call, and the business reason the step exists. Only error handling and re-send/rate behavior remain unstated.

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 explains the single email parameter, including the 'inbox you or your operator can read' constraint. The description's mention that a code is sent to the address is behavioral context rather than added parameter meaning, so the baseline 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 makes clear this attaches an email to a partner account created without one, and that a verification code follows. The resource and operation are identifiable, though the sentence structure leads with the auth requirement rather than the verb, so it is slightly less crisp than a direct 'adds X to Y' statement.

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 names the triggering condition ('an account that joined without an email') and the mandatory follow-up step with a named sibling ('confirm it with partner_confirm'), plus the prerequisite for payouts. It stops short of an explicit exclusion (e.g., what to do if an email already exists), so it falls just below a full routing instruction.

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