ack

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

With no annotations, the description carries the full behavioral burden. It usefully discloses the monotonic constraint ('Cursors only move forward'), implying re-acking an older cursor is a no-op, but it omits the mutation/irreversibility profile, error behavior for invalid cursors, and permission requirements.

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?

Three short sentences, front-loaded with the action and constraint, no filler. Every sentence adds distinct information.

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 output schema or annotations, the essential workflow is present, but the success/failure outcome and the consequence of marking events handled (a mutation with no undo noted) are left unstated.

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 compensate. It clarifies the cursor's origin ('Pass next_cursor from since()') and that ack applies 'for agent_id', but never explains agent_id's default or the cursor's format/range.

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 ... events ... as handled') and bounds it precisely with 'up to and including cursor ... for agent_id'. It also distinguishes itself from the sibling since() by referencing where the cursor value comes from.

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?

Tells the agent how to use it in the flow ('Pass next_cursor from since()'), which is effectively the calling context. It does not state when not to use it or what happens if ack is called outside that flow, so it falls short of the explicit when/when-not bar.

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