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

Annotations already declare the write/idempotent/destructive profile, and the description adds genuinely useful context beyond them: partial-update semantics ('changes only the settings given'), per-user scoping, and the fact that all settings are returned post-change. It could have been more explicit about the blast radius of setting the master email switch off, which is what makes destructiveHint=true meaningful.

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?

Three tight sentences: trigger condition first, then semantics of the change, then exclusions. No filler and nothing repeated from the schema or annotations.

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 13-parameter all-optional patch tool with full schema coverage and no output schema, the description covers when to use it, partial-update behavior, user scoping, and what is returned. The only unstated piece is permissioning and whether a paused state can block critical alerts, which is a modest gap.

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% with per-field descriptions for all 13 booleans and the three SSL day thresholds, so the schema carries the parameter burden. The description adds only a little beyond it, referencing 'when SSL expiry warnings arrive' and the alert kinds at a high level; baseline 3 is appropriate.

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 a precisely scoped resource (the calling user's alert email preferences), with concrete examples of what can be changed (alert kinds, pause/resume, SSL expiry warning timing). It also names what it is not for (teammates' alerts, webhooks, chat channels), so an agent can separate it from sibling notification and webhook tools.

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?

'Use this when the user wants...' gives clear triggering conditions, and the closing exclusion sentence blocks the most likely misrouting (other people's alerts, webhooks, chat channels). It stops short of explicitly naming get_my_notifications as the read-only counterpart, but the 'returns all of them after the change' phrasing implies the read path.

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