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

Annotations only supply readOnlyHint=false; the description adds the materially useful warning that this changes stored state and is 'not safe to repeat blindly,' which is exactly the idempotency caveat an agent needs. It still omits what state is destroyed (skipped messages) and any auth/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 tight sentences, front-loaded with the action, then the parameter choice, then the write warning. No filler, though the parenthetical cursor syntax makes it slightly dense.

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?

No output schema exists and annotations are minimal, so the description carries the burden for a state-mutating tool. It covers the mutation risk and cursor semantics reasonably, but the undocumented `secret` parameter and unstated consequence of acknowledging (messages no longer surfaced) leave real gaps.

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 carry the load. It explains the two shapes of `up_to` and why the structured form is lossless, but leaves `secret` entirely unexplained and never clarifies the embedded version/timestamp/comments/mentions/seal fields, so it only partially compensates.

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 concrete effect on a concrete resource: advancing inbox acknowledgment state, with the title reinforcing 'Acknowledge your inbox'. It does not reference or differentiate itself from nearby siblings such as me, me_cadence, or changes, so it stops short of a 5.

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 clearly helps the caller choose between the two `up_to` encodings and points at me(cursor_mode='id') as the source of the structured cursor, which is genuine routing value. However it gives no guidance on when acknowledging is appropriate at all (e.g., after reading vs. after processing), and no exclusions or prerequisites.

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