Unread notifications count

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

Annotations already declare readOnlyHint=true and openWorldHint=true, and the description adds useful context about the 'cheap' nature of the operation and the authenticated-account scope. It does not over-detail or contradict the annotations. This is appropriate for a simple count operation with an output schema.

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?

A single, well-structured sentence packs the return value, scope, and usage hint without any wasted words. Every clause adds meaning and the key purpose is front-loaded.

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?

Given the zero-parameter input, the openWorldHint/readOnlyHint annotations, and the presence of an output schema, the description covers all the essential information an agent needs: what is counted, for whom, and when to use it. Nothing critical 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 schema coverage is 100%, so there are no parameter semantics to clarify. The description appropriately focuses on the return concept ('how many') rather than repeating schema information.

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 ('Return'), a concrete resource ('in-app notifications'), and a precise scope ('unread for the authenticated account'). It clearly differentiates from the sibling list_notifications by being a count rather than a full list. This is immediately disambiguating for an agent.

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 phrase 'a cheap check before fetching the full list' gives clear contextual guidance on when to invoke this tool, implying it should be used as a lightweight precursor to list_notifications. It does not explicitly name the alternative or provide exclusions, so it stops short of a 5.

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