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

With no annotations, the description carries full responsibility for behavioral disclosure, and it delivers. It reveals that the account is provisional, that a human must click the verification link, that the deadline is 30 days, and that the account and its domains will be deleted if verification doesn't happen. This is exactly the kind of side effect an agent needs to know before calling a mutation tool.

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 only two sentences long, yet it packs the core action, the required human action, the deadline, the deletion consequence, and the usage timing. Every sentence earns its place, and the most important directive is front-loaded.

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 tool with no output schema and no annotations, this description gives an agent enough to decide when to call it, what input to provide, and what significant behavioral risks exist. The only minor gap is that success/error response behavior is not described, but that is not essential for invoking such a tool correctly.

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?

The input schema already provides complete coverage of the only parameter, including its type and intended meaning. The description adds essentially no semantic information beyond what the schema states, so the baseline 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 states a specific action ('attach an email address'), the resource ('the account'), and a concrete follow-up behavior (sending a verification link). It also ties the tool to the signup flow, making its purpose easy to distinguish from domain-related siblings like claim_domain or set_forward.

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 explicitly says 'Use this right after signup,' giving the agent a clear temporal instruction for when to invoke this tool. It does not explicitly name alternatives or exclusions, but the placement in the signup flow makes the intended context unambiguous.

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