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

With no annotations, the description supplies meaningful behavioral context: moving is a real move, batching is handled internally, and per-message failures are reported instead of aborting. It does not cover edge cases such as invalid folder IDs or whether moves are reversible, but the core side-effect behavior is disclosed.

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 with no fluff; the core action is first, followed by the key distinction and the batch/failure behavior. Every clause adds value.

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 three-parameter mutation tool with no output schema and no annotations, the description covers the key execution behavior (real move, batching, failure reporting). Minor gaps remain: it never mentions resolving destinationFolderId via list_mail_folders or what happens when the destination folder does not exist.

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 only 33% and the free text adds little parameter-level detail. 'messages' and 'folder' merely restate the property names, and while 'any number of messages' reflects the array type, destinationFolderId and messageIds formats/sources are not clarified.

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 the exact operation: move messages into a folder, and explicitly differentiates from a label change ('real move, not a label change'). This distinguishes it from label-related siblings such as apply_gmail_labels.

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 phrase 'real move, not a label change' gives a clear exclusion: do not use this tool when a non-destructive label/tag operation is intended. However, it does not explicitly name an alternative tool or state conditions like requiring an existing destination folder.

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