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

Annotations already declare this is a non-destructive mutation with openWorldHint=false and idempotentHint=false, so the safety profile is covered. The description adds that a null daily_cap resets to the default, which is real behavioral information, but it does not say whether omitted fields are left untouched (partial vs full update), what permissions are needed, or what the call returns.

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?

A single front-loaded sentence that names the fields and packs the two non-obvious constraints inline. Nothing is wasted and nothing essential is buried.

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 4-parameter mutation tool with no output schema and light annotations, the description covers parameters well but leaves the update semantics ambiguous — whether calling with just email is a no-op, whether unspecified fields are preserved, and what a successful response looks like. It is adequate but has clear gaps.

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 only 25% (only email is documented), so the description must and does compensate: it gives the daily_cap range (1-100) and the null-means-default sentinel, plus the IANA format for timezone with an example. Only the display-name parameter gets no extra semantics, which is fair for a simple string.

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 (change) and resource (mailbox) and enumerates the three mutable fields, so the agent can immediately tell this is a settings update rather than pause/resume/remove/move. It does not explicitly contrast with the many sibling mutation tools (pause_mailbox, move_mailbox_to_workspace, remove_mailbox), which keeps it below a 5.

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?

There is no when-to-use or when-not-to-use guidance and no named alternative. The reader must infer that this is the tool for editing mailbox attributes instead of its siblings such as pause_mailbox or move_mailbox_to_workspace.

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