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

Annotations already flag destructiveHint=true and idempotentHint=true, so the description's added value is the non-obvious exception: action_needed notifications remain unread until handled. That is real behavioral disclosure an agent cannot infer from annotations. It does not say what happens with invalid or already-read ids, keeping it below a 5.

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 compact sentences with zero filler, front-loading the action and following with the id source and the exception. Every clause 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 single-parameter mutation with no output schema, the description covers action, input source, batch bound, and a key side-effect caveat. A brief note on reversibility or handling of unknown ids would close the remaining gap given destructiveHint=true.

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 0%, so the description must carry the load, and it does: the single 'ids' parameter is described as coming from list_notifications with a 1-100 count bound. The UUID format and exact bounds are already in the schema, so it adds meaning rather than repeating it verbatim.

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 (marks as read) and resource (notifications), and ties the input to list_notifications, so an agent can distinguish it from the sibling read/list tools without inspecting schemas.

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 tells the agent where the ids must come from (list_notifications) and bounds the batch at 1 to 100, which is the practical precondition for calling it. It stops short of naming an alternative tool or an explicit when-not-to-call case, so it is clear context rather than full routing guidance.

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