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

Annotations already cover the safety profile (readOnly=false, destructive=false, idempotent=false), so the bar is lower. The description adds genuinely non-obvious context the annotations do not: the required key type and the fact that workspace keys are rejected. It does not discuss idempotency or reversibility, so it falls short of a 5.

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?

Two compact sentences, front-loaded with the scope ('calling user's ... only') before the auth constraint. No filler or redundancy.

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 auth requirement is covered. But for a tool whose sole parameter is a nested object with a 'clear' flag and multiple enums, the description leaves the mutation semantics unexplained, which is a notable gap for a write operation.

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 effectively 0% for the nested object's meaningful fields (clear, value, category, weeklyReport); only the nested workspaceId carries a description. The description merely restates the parameter name ('notification preferences') and adds no semantics for the 'clear' flag, the immediate/off value, or the category enum. With low coverage, the description fails to compensate.

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 with scope: 'Edit the calling user's notification preferences only.' The word 'calling user's' and 'only' usefully delimit it. However, it does not explicitly differentiate from the adjacent sibling campaignstack_edit_notifications, which an agent could easily confuse it with.

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?

Gives a clear precondition and an exclusion: a user API key is required, and workspace keys cannot change personal preferences. That is real when/when-not guidance for auth context, though it never names the alternative tool to use for workspace-level preferences.

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