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

Annotations only mark it non-read-only and open-world; the description adds the concrete side effect (an email with a 6-digit code is sent to the owner) and the dual new/existing account behavior. It does not disclose code expiry, resend/rate limits, or what the call returns, which matters since there is no output schema.

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?

Four short, front-loaded sentences with zero filler; the action, applicability, and next step are each stated once.

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 one-required-param trigger tool with no output schema, the description covers purpose, effect, and follow-up call. The main remaining gap is the response shape and whether a session/identifier is returned to pass into verify_signup.

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 email and name are already documented as the owner's address and name. The description adds only a slight hint that the target is the 'product owner'; it adds no format or conditional semantics (e.g., whether name is ignored for existing accounts).

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?

States a concrete action and its effect: emails a 6-digit code to the product owner to begin signup. It also positions itself as step 1 ahead of verify_signup, so the agent can tell it apart from the verify/claim siblings.

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?

Clear sequencing guidance ('Step 1... Then call verify_signup') and a qualifying fact that it works for both new and existing accounts. It stops short of naming when a different path (e.g., login_link for an existing account that just needs a link) would be preferable.

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