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

Annotations already flag destructiveHint=true and readOnlyHint=false; the description adds genuine beyond-annotation behavior: 'Only the fields you pass change' (partial-update semantics), that display_name feeds the {{sender_first_name}} personalization variables, and that mailboxes have no time zone so sending hours follow the campaign. It does not spell out what the destructive mutation can disrupt (e.g., what pausing an active mailbox does to in-flight campaigns), so it falls just short of full disclosure.

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?

Front-loads the action and field list, then the alternative-tool routing, then caveats — a sensible ordering with no filler sentences. The trailing docs URL is slightly extraneous but does not obscure the core instructions.

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?

An output schema exists, so return values need no explanation, and the description covers scope, partial-update behavior, sibling routing, and the display-name variable side effect. The only real gap for a destructive mutation tool is that it doesn't state permission/ownership requirements or the operational consequence of flipping 'active' on a live mailbox.

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 description coverage is 100%, so the baseline is 3; the description earns extra by explaining that display_name is read by sender personalization variables and by reinforcing partial-update semantics ('only the fields you pass change') for the nested settings object. It still doesn't clarify the warmup/warmup_per_day interaction, but that pairing is partly covered by the schema.

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 ('Change one mailbox's') and enumerates the exact mutable fields (daily limit, warm-up on/off and emails a day, active state, display name). An agent can immediately distinguish it from sibling tools like argorant_update_inboxes or argorant_set_inbox_signature.

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?

Explicitly routes between alternatives: 'Use it for one mailbox; for many at once use argorant_update_inboxes, and for signatures use argorant_set_inbox_signature.' Both the when-to-use and the when-not-to-use cases are stated with the named substitute.

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