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

Annotations already declare readOnlyHint=false, openWorldHint=false, and destructiveHint=false, so the safety profile is covered. The description adds meaningful behavior beyond that: it is a true folder move, not a label change; it batches internally to handle any number of messages; and it reports individual failures instead of aborting the batch.

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 core action. Each sentence earns its place by adding scope, distinction from labeling, and batching/failure behavior.

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-required-parameter mutation tool with no output schema and low schema description coverage, the description is only partially complete. It explains the move behavior and failure handling well, but it omits how to obtain or format destinationFolderId and leaves mailbox authorization guidance to the schema alone.

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%, so the description needs to compensate for undocumented parameters. It generically says 'messages' and 'folder' and hints that any number of messages can be moved, but it gives no guidance for destinationFolderId format or source and does not meaningfully explain mailbox, messageIds, or destinationFolderId beyond the schema's own names.

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 the verb and resource precisely: 'Move messages into a folder.' It also immediately distinguishes the operation from a label change, so an agent can identify it among the many sibling mail tools without ambiguity.

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?

Gives clear context by saying this is a real move rather than a label change, which helps separate it from label-oriented siblings. However, it does not name an explicit alternative such as apply_gmail_labels or update_agentmail_labels for cases where labeling is desired, so it stops short of full when-to-use routing.

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