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

Annotations already declare readOnlyHint=false, idempotentHint=true, and destructiveHint=false, so the safety profile is covered. The description adds the non-obvious behavioral requirement that user confirmation is needed, complementing the confirmation_token workflow documented in the schema.

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 tight sentences with zero filler; the two operational modes are front-loaded and the confirmation prerequisite follows. 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 mutation tool with no output schema, the description covers scope selection and the confirmation prerequisite, and the schema details the token round-trip. It stops short of describing what happens to already-read notifications or what the confirmation summary contains.

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 only 33% (only confirmation_token is annotated), so the description must compensate. It does explain the meaning of notification_id and the all: true switch, but adds no format, bounds, or mutual-exclusion semantics beyond what the parameter names imply.

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 and resource ('Mark ... as read') and enumerates both scopes: a single notification via notification_id or the whole set via all: true. An agent can immediately tell this apart from the read-oriented get_notifications sibling.

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 signals both invocation modes and states the precondition that the user's confirmation is required, which is the key gate for this tool. It does not, however, mention any when-not conditions or compare itself to siblings like get_notifications.

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