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

Beyond the destructiveHint=true annotation, the description discloses the full proposal/confirmation mechanic: status='confirmation_required', an action_id, a plan_token, and that the write only occurs after confirm_action. It also clarifies the non-obvious side-effect boundary (the label entity survives), which annotations cannot convey.

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 operation, followed by the side-effect clarification and a labeled CONFIRMATION block. No filler and nothing buried.

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 destructive, confirmation-gated mutation with no output schema, the description covers the critical behavioral contract. The remaining gap is parameter-level detail on the batch of message_ids and how failures among them are handled.

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 carries the full burden of explaining the two parameters, but it only alludes generically to "messages" and "a label." It says nothing about the 1–50 batch limit, accepted ID types, ordering, or partial-failure behavior.

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 ("Take a label off messages") and immediately scopes it with "The label itself is not deleted," which separates it from any label-deletion sibling. It stops short of naming a sibling, but the operation 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 clear usage context by explaining that this tool is never executed directly and must go through confirm_action, which is exactly what an agent needs to know before calling it. It doesn't state prerequisites such as the label already existing or what happens when some message_ids are invalid.

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