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

Annotations mark this destructiveHint=true, and the description adds the crucial behavior neither annotation nor schema conveys: the call is only PROPOSED, returning status='confirmation_required' with an action_id and plan_token, and the write happens only after confirm_action. It also clarifies reversibility (messages can be moved back), which softens the destructive hint meaningfully.

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?

Front-loaded with the core action, then source, then the non-deletion clarification, then a clearly labeled CONFIRMATION block. No filler; every sentence carries operational meaning.

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 mutation with no output schema, the description covers the safety-critical confirmation protocol and reversibility, which is what an agent most needs. Residual gaps are minor: batch size limit and the apparent mismatch between the described targets (archive, spam, trash) and the schema enum that only lists 'trash'.

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 67%, and the description compensates by explaining what message_ids contains (ids from mail_list_messages) and that the source folder is implicit per message. It loosely describes target/target_folder semantics ('archive, spam, trash or any folder from mail_list_folders'). It does not mention the 50-id batch cap or clarify that the schema's target enum currently only accepts 'trash', which is a mild gap.

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 first sentence gives a specific verb and resource (move messages to another folder) plus the set of possible targets, and it names the sibling tools that supply inputs (mail_list_folders, mail_list_messages). It also distinguishes itself from the delete family by stating the messages are NOT deleted.

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 clearly says where ids come from and that the source folder is derived from each stored message, so an agent cannot mis-specify the origin. The confirmation flow with confirm_action is spelled out. What's missing is an explicit exclusion such as 'do not use this to remove mail permanently — use mail_delete_*', though the non-deletion sentence implies it.

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