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

The description adds important behavioral detail beyond the annotations: it only moves forward, and a lower value returns the current position without error. This clarifies the monotonic and idempotent-like behavior of the acknowledgment. It does not describe authentication needs or the exact response shape, but the output schema covers the latter.

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 two short sentences with no wasted wording. The core operation is front-loaded, followed immediately by the important forward-only constraint.

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?

Given the tool's low complexity, one required parameter, existing output schema, and annotations, the description provides enough context to invoke it correctly. It could mention where to obtain a valid event sequence or how this relates to list_inbox, but the essential behavior is covered.

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?

The single parameter is named up_to_event_seq and has 0% schema description coverage, so the description must carry the semantic burden. It explains that the value is an event sequence number and that lower values return the current position without error, adding meaningful behavior beyond the bare integer schema.

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 and resource: 'Mark your inbox read up to an event seq.' It is clear what the tool does, though it does not explicitly distinguish itself from siblings such as list_inbox or mark_read.

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 implies usage when marking the inbox read up to a sequence number, but it gives no explicit guidance on when to use this versus alternatives like list_inbox or poll_events. The intended context is understandable but not fully specified.

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