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

The description adds substantial behavior beyond annotations: partial-update semantics, null-clears-to-default behavior, the confirmed=true approval requirement, and the fact that writes are never retried automatically. These details materially inform safe invocation of a destructive, non-idempotent mutation.

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 short and front-loaded, with the core partial-update behavior and approval prerequisite stated early. The first two sentences are somewhat redundant, but the remaining sentences carry useful, non-repetitive behavior details.

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 nested-object mutation tool with annotations and no output schema, the description covers the key invocation semantics: partial updates, null clearing, approval confirmation, and no automatic retries. It does not describe response or error behavior, but the essential information needed to call it correctly is present.

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?

The schema documents the individual settings fields, and the description adds crucial body-level semantics: only included fields are changed, omitted fields are untouched, and null clears a setting to its default. The confirmed parameter's approval meaning is also reinforced in 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?

The description states a specific verb and resource: update organization-level mail settings. It is clear enough to distinguish from read-only sibling tools like get_mail_settings, but it does not explicitly name an alternative or sibling for routing.

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 explains the update context and prerequisite that user approval plus confirmed=true are required before changes or credit use. It does not explicitly address when not to use this tool or name a read/view alternative, but the usage context is clear.

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