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

With no annotations, the description carries the full burden and does well: it discloses that both modes are idempotent, that scope:through spans ALL event types (a broad side effect), and warns to process desired pages before acknowledging. It omits permission/auth requirements and any mention of a return value, but the key behavioral traits are present.

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?

It is a single dense sentence with zero filler, front-loading the two scope behaviors before the operational caveats. The telegraphic style ('scope:event', 'scope:through') is compact but slightly terse for first-time readers.

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 two-parameter mutation tool with no annotations and no output schema, the description covers what each mode does, idempotency, and pagination sequencing. A brief statement of the return value and any permission prerequisite would close the remaining 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 0%, so the description must compensate, and it largely does: it defines scope:event as marking only eventId read and scope:through as marking every event through eventId across all types, effectively documenting both the enum and the eventId role. Only minor detail (Idempotency per-mode boundaries, eventId format) is left implicit.

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 conveys a specific operation: marking inbox events as read, distinguishing the two scope behaviors (single event vs. everything through eventId across all types). It does not name the sibling get_inbox or use the word 'inbox', so differentiation relies on the reader inferring the counterpart, but the action itself is unambiguous.

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 operational guidance: process the desired pages first, and restart unread pagination after read-state changes. It also explains the condition selecting each scope. It stops short of explicitly contrasting with get_inbox, but the when/how to use each mode is clear.

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