rename_mailbox

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

Annotations already indicate this is a non-read-only, non-destructive operation. The description adds minimal behavioral context by mentioning the need to list current paths, but doesn't explain side effects like renaming implications on subfolders or references. With annotations present, a 3 is appropriate.

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?

Two sentences, zero fluff. The purpose is front-loaded and the additional sentence provides actionable guidance. Perfectly concise.

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 rename tool with three required parameters and no output schema, the description is adequate. It explains the action and gives a pointer to list mailboxes. It could mention what happens to the contents or subfolders, but that level of detail isn't strictly necessary for correct invocation.

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 100%, so the schema already documents all three parameters. The description doesn't add extra parameter-level meaning beyond the schema, which gives a baseline of 3.

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 clearly states the tool renames an existing mailbox/folder, with a specific verb and resource. It distinguishes from sibling tools like create_mailbox and delete_mailbox, and even hints at the prerequisite of listing mailboxes first.

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 explicitly tells the user to use list_mailboxes to see current folder paths, which is a clear prerequisite. However, it does not mention alternatives or when not to use this tool, so it's not a full 5.

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