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

Annotations already cover readOnly=false, idempotent=true, openWorld=true and destructive=true, so the safety profile is largely given. The description still adds real value beyond them: the asynchronous nature of the `failed` recovery and the caveat that the response may keep showing `failed`/`checking` until the test settles. It does not address why the operation carries a destructive hint (resuming may start outbound sending).

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?

One front-loaded sentence opens with the action, then branches cleanly on mailbox state, with the only parenthetical reserved for a genuinely surprising async caveat. No filler or repetition.

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 one-parameter state-change tool with no output schema, the description supplies the essential pieces: what it mutates, the two state branches, and why the observed result may lag. The remaining gap is that it never explains the destructive/idempotent implications an agent might weigh before invoking.

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?

There is a single parameter and schema description coverage is 100% (the schema documents `id` as a UUID mailbox id), so the schema carries the semantics. The description adds no format, constraint, or identifier nuance beyond it; baseline 3 applies.

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 and resource ('Bring a mailbox back') and elaborates the two exact state transitions it performs (`inactive` → sending, `failed` → connection test → service). The reversal of pause_mailbox is implicit in the verb, but no sibling is named, so an agent gets clarity without explicit differentiation.

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 effectively defines the trigger conditions by describing exactly which mailbox states it applies to (paused/inactive, failed), which tells the agent when this tool is the right call. It stops short of naming alternatives, e.g. check_oauth_connect or delete_mailbox, or saying when NOT to resume.

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