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

No annotations are provided, so the description carries the behavioral burden. It explicitly says 'Read-only,' which correctly discloses the safety profile, but it does not cover permissions, rate limits, or what happens when there are no unread notifications.

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 two short fragments with zero waste. The key fact (unread count) is front-loaded, followed by the clarifying parenthetical and safety note.

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 simple zero-parameter count tool with no output schema, the description is almost complete: it says what is counted and that it is read-only. It leaves out scope details such as whether the count is workspace-wide or user-specific, which keeps it from a 5.

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 schema coverage is 100%, so there is no parameter semantics to add. The baseline for a parameterless tool is 4.

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 states a specific verb-like resource (number of unread in-app notifications) and clarifies it with '(the bell badge),' making the metric unambiguous. It does not explicitly differentiate from siblings like list_app_notifications or mark_app_notification_read, which keeps it from a 5.

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 gives no guidance on when to use this tool versus alternatives such as list_app_notifications or mark_app_notification_read. It only names the metric and notes it is read-only; any when-to-use meaning is left implicit.

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