Count unread notifications

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

Annotations already cover readOnlyHint, idempotentHint, and destructiveHint, so the description doesn't need to restate them. It adds context about being 'one cheap call', which is useful. It doesn't detail what 'seen' means or how the count is calculated, but the annotations are sufficient for a baseline.

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 sentences, with the purpose front-loaded and the recommended usage immediately following. Every word earns its place.

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 read-only count tool with zero required parameters and no output schema, the description is complete enough to invoke correctly. The only minor gap is not mentioning the output format, but the lack of an output schema makes that less critical.

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 100%, so the description doesn't need to add parameter details. The description does not go beyond the schema, but since the schema covers everything, a 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?

The description clearly states what the tool does—'How many notifications have arrived since you last marked them seen'—which uses a specific verb and resource, and distinguishes it from related tools like get_notifications and mark_notifications_seen.

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 clear context for when to use it ('before you pull the full list') but does not explicitly exclude alternatives or mention when not to use it. The sibling tool get_notifications exists, so differentiating it further would have earned a 5.

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