iam_email

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

With no annotations, the description carries the full burden and does disclose non-obvious behavior: owner enrollment is required, registration does not confer sending permission, old addresses persist as aliases, and no outbound mail is emitted. These are exactly the facts an agent could not infer. It still omits idempotency (what happens on re-register) and failure modes.

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?

Front-loaded with the three operations before the caveats, and the telegraphic sentence fragments are dense rather than padded. Every clause carries information; the clipped style is slightly at the cost of readability but wastes nothing.

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?

An output schema exists, so return values need not be described. But for a three-action, three-parameter tool with zero schema documentation, the missing action-to-parameter mapping leaves a real hole in an otherwise thoughtfully annotated definition.

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 0%, so the description must compensate, and it largely does not. It names the action values but never explains the 'local' or 'mailbox' parameters, nor which parameters each action consumes — an agent cannot tell whether 'register' takes local, mailbox, or both.

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 names three concrete operations (check availability, register address, inspect status) on a specific resource (iam_email), and the stated action values available/register/status let an agent separate this from siblings like iam_send or iam_reply. It stops short of a single crisp one-line purpose statement, but the function is unambiguous.

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 action list (available/register/status) gives implied routing, and 'Owner enrollment required' is a genuine prerequisite. However, there is no explicit guidance on when to choose this over iam_list_mailboxes or iam_whoami, and no indication of what to do if enrollment is missing.

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