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

Annotations already establish readOnlyHint=false and idempotentHint=true, which the description does not contradict. The description adds value beyond annotations by disclosing the return value (count of updated notifications), the 404 failure mode when the feature is disabled, and the team-scoping constraint. No annotation contradiction.

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?

Three sentences with zero filler. The action is front-loaded, followed by the return value, then the feature prerequisite. Each sentence earns its place; the description is compact and scannable.

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 single-optional-parameter tool with 100% schema coverage and safety annotations, the description covers action, scope, return value, and error condition. The only minor gap is a slight ambiguity about whether 'all notifications' means all of the user's notifications within the team or all team notifications, and it does not mention related read-state tools. Otherwise, nothing needed for a correct call 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?

Schema coverage is 100%: the team_id parameter already carries a rich description (API key pinning, OAuth multi-team behavior, fallback and rejection rules). The tool description adds mild framing by referencing 'the authenticated user's current team,' but the schema does the heavy lifting for parameter semantics. 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 states a specific verb ('mark') and resource ('all notifications') with an explicit scope ('the authenticated user's current team'). The word 'all' inherently distinguishes it from siblings markNotificationRead and markNotificationBatchRead, and 'mark as read' distinguishes it from deleteAllNotifications/deleteReadNotifications. Purpose is unambiguous.

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 a clear precondition ('Requires the Notification Center feature; returns 404 when not enabled') that tells an agent when the tool is available, and the scope ('current team') frames when it applies. However, it does not explicitly name alternatives or give when-not-to-use guidance (e.g., when a batch subset is preferred over all notifications). Usage context is implied rather than spelled out.

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