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

Annotations already declare mutation, idempotency, and destructive behavior, so the description's main added value is the authorization requirement and the validation rule that a caller requesting no alerts is refused. It also clarifies the self-only scope. It does not elaborate on the destructive implication of disabling alerts, but annotations cover that 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?

The description is front-loaded with the core action and stays relatively compact. The long semicolon-delimited sentence and incomplete alert-type list slightly reduce clarity, but there is little waste.

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 rich schema and annotations, it covers scope, authorization, validation, and update modes. The main completeness gap is the omitted analyst_brief alert type in the description's enumeration; otherwise an agent has enough context to call it 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?

Schema coverage is 100%, so the schema already documents nested preferences and delivery fields. The description adds useful top-level semantics, notably that callers may send preferences, delivery, or both and must name at least one alert type. However, its list of alert types omits analyst_brief, which is a valid field in both schema objects, making the enumeration incomplete.

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 verb and resource: turning email alert types on/off or choosing immediate vs daily delivery, scoped to the caller in their workspace. It clearly distinguishes this mutation from related read tools such as get_alert_preferences, even without naming that sibling.

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?

It gives clear context for when to call this: to change one's own email alert delivery or enablement, sending preferences, delivery, or both. It does not explicitly name get_alert_preferences as the alternative for viewing current settings, so the when-not guidance is incomplete.

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