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

Annotations already convey the important behavior: idempotentHint=true, destructiveHint=false, readOnlyHint=false. The description adds only the singular-vs-bulk scope, and says nothing about what happens when the notification is already read, permission requirements, or the response. With annotations covering the safety profile, this is adequate but thin.

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?

One sentence, front-loaded with the action and ending with the disambiguation clause. Nothing superfluous.

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 trivial one-parameter, idempotent mutation with full annotation coverage and no output schema, the description gives everything needed to invoke it correctly. A brief note on the return (e.g. updated notification) is the only gap.

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% and the single id parameter is documented in-schema with its source ("from list_notifications"). The description adds no format or sourcing detail beyond that, so it sits at the baseline where the schema does the work.

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?

States a specific verb plus singular resource ("Mark one notification as read") and immediately scopes it against the bulk sibling mark_notifications_read. An agent can distinguish it from the sibling without opening either schema.

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 parenthetical explicitly names the alternative tool and the condition that selects it ("for all of them"), which is exactly the single-vs-bulk routing decision the agent needs. No ambiguity remains about which tool to pick.

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