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

Annotations already declare the mutation profile (destructiveHint=true, idempotentHint=true, openWorldHint=true), so the description's job is to add context beyond them, which it does via the 409 conflict path and 422 validation failure on the new address. It stops short of saying what happens to the previous address or existing signature installations tied to it.

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?

Two tight sentences that front-load the operation, then the availability constraint, then the failure modes. No filler and no repetition of the title or schema.

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, and the description covers the key operational constraints and error codes. It is nearly complete for a mutation tool, with the only gap being the side effects of replacing an address (e.g., downstream signature or teammate references).

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 the baseline is 3; the description adds genuine meaning by noting the address is validated and that this applies to both primary and alias addresses, clarifying intent beyond the schema's plain "The new email address." The required `context` analytics parameter is only explained in the schema, not the description.

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 precise verb and resource ("Change an email's address") and adds scope coverage for both primary and alias addresses. It is unambiguous against siblings like create_email or delete_email, though it never names a sibling explicitly to route the agent.

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?

Gives an explicit precondition and an explicit exclusion condition: usable only when the workspace manages its own team list, and a directory integration produces a 409 conflict. An agent can decide up front whether this call is even legal in the current workspace.

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