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

With no annotations provided, the description carries the behavioral burden and does so well: it discloses that the default can affect events across ALL types, that both scopes are idempotent, and that read-state changes affect unread pagination. It does not mention permissions, return values, or irreversibility, but the key side effects are surfaced.

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 description is dense and every clause adds useful information, with the default scope front-loaded. The compressed em-dash style is slightly difficult to parse, but the length is appropriate for a two-parameter tool.

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 simple two-parameter tool with no annotations and no output schema, the description covers core behavior, scope semantics, idempotency, and pagination side effects. It stops short of describing the return shape or error behavior, but the agent has enough to call the tool correctly.

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 description coverage is 0%, so the description must explain the parameters, and it does. It clarifies both scope enum values and the default behavior; eventId is also self-explanatory from the name and required field. The remaining details like maxLength live in the schema, but the semantic distinction between event and through is fully explained.

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 clearly states that the tool marks events as read, with eventId as the primary resource and scope controlling how many events are affected. It is specific about behavior, though it does not explicitly frame the action as an inbox acknowledgment or distinguish itself from read-only siblings like get_inbox.

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 concrete usage guidance: use scope:event to mark only the given event, or default scope:through to mark all events through eventId across all types. The warning to process desired pages first and the note about restarting unread pagination after read-state changes add practical when-to-use context, though it does not name alternative tools or state explicit when-not-to-use conditions.

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