request_email_change

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

Annotations already declare this is a non-read-only, non-destructive, non-idempotent, open-world mutation; the description adds the key behavioral constraint that self-service only applies to the token's subject, which an agent could not infer from the schema. It doesn't say what the request produces (verification email, pending state), leaving a modest gap given annotations cover the safety profile.

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 front-loaded with the action and its endpoint, then the authorization rule. Minor redundancy from restating the title/tool name verbatim in the opening fragment, but no wasted prose.

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 mutation tool with no output schema, the description covers the authorization prerequisite but not the outcome: whether a verification email is dispatched, whether the change is pending/confirmed, or how conflicts (address already in use) behave. Adequate but with meaningful gaps for an agent deciding whether to call it.

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%, so baseline is 3, and the description earns above baseline by constraining userId semantically (must be the token subject) rather than restating the schema's generic "identifier of the user." x-trace-id remains unexplained in the description, but the schema documents it.

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 specific verb+resource ("Request an email change for the specified user") and pins the endpoint POST /v1/users/{userId}/mail-change-requests, which distinguishes it from other user-identity tools. It does not explicitly contrast with near neighbors like resend_email_verification or update_user, but the action 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?

Gives a clear eligibility rule: available to account owners and sub-users, but only for their own identity, with userId required to match the access token subject. That is strong when-to-use context, though it offers no exclusion pointing at an alternative tool for changing someone else's email.

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