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

Annotations already cover readOnlyHint, idempotentHint, and destructiveHint, so the safety profile is clear. The description adds meaningful behavioral context beyond this by specifying the calling-user scope, the auth-key requirement, and the structure of the returned data (delivery matrix + weekly report opt-in). It does not detail the exact return schema, but the described contents are sufficient for a zero-parameter read operation.

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?

The description is compact and front-loaded with the core purpose, then adds only high-value context: the exact returned components, the required API key type, and the update alternative. No filler or redundant phrasing exists.

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 zero-parameter, read-only getter, the description is complete: it names the resource, the return contents, the auth constraint, and the sibling tool for mutations. Annotations cover side-effect safety, so no additional behavioral disclosure is necessary. Nothing an agent needs to call this correctly is missing.

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?

The tool has zero parameters, and the schema reflects this with an empty properties object, so there is nothing for the description to clarify. The baseline for 0-parameter tools is 4, and the description appropriately focuses on the implicit user identity rather than parameter details.

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?

The description uses a specific verb ('Get') and names the exact resource: the calling user's notification email preferences. It further details the resource as the per-category email delivery matrix with global defaults, per-workspace overrides, inherited markers, and the weekly report opt-in, distinguishing it from notification-list tools like list_notifications.

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?

The description explicitly states the auth prerequisite: a USER API key (csu_) is required, and workspace keys have no user identity, so the tool cannot be used with them. It also names the update counterpart, campaignstack_update_notification_preferences, for changing values, making the when-to-use vs. when-not-to-use guidance explicit.

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