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

Annotations already declare the mutation/idempotent/non-destructive profile, so the description is not carrying the safety burden. It adds genuinely useful behavioral context beyond them: the return value (count of updated members), the Notification Center feature dependency, the exact 404 conditions, and the side effect that openedFrom is stamped on every member marked.

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 core action is front-loaded in the first sentence, followed by parameter-scoping rules and error conditions in a logical order. It is dense rather than padded, though a couple of clauses (the 'e.g. the page's active filters' aside) are mildly verbose.

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 6-parameter mutation with no output schema, the description covers the essentials: what gets updated, what narrowing does, the return count, feature gating, and 404 failure modes. Nothing critical for correct invocation appears missing, though it could note whether already-read members are excluded from the returned count.

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?

With only 33% schema description coverage, the description compensates well: it clarifies that severity is exact while minSeverity is a threshold and that the two are mutually exclusive, explains that types narrows the mark to member types, and defines openedFrom as the channel recorded on every newly read member. The id/team_id behavior is left to the schema, but the substantive gaps are covered.

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 and resource — mark every unread live member of a notification batch as read for the authenticated user — which is far more precise than the title restatement. It is implicitly distinguishable from markNotificationRead and markAllNotificationsRead via the 'batch' scope, but it never names those siblings explicitly, so a 4 rather than 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?

It gives clear when-to-narrow guidance ('pass types to narrow', 'omit them to mark every live member') and explains the rationale ('the rows marked read should be the rows the card counted'). It does not, however, contrast this with the single-notification or mark-all siblings, leaving that routing to inference.

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