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

Annotations already declare destructiveHint=true and readOnlyHint=false, so the destructive nature is covered. The description adds operational caution: 'verify target' and the 'exact' match requirement, plus the explicit ID-type warning. It does not disclose downstream effects (e.g., whether messages inside the folder are deleted), but the annotations carry the primary behavioral burden and the description adds useful safety context.

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?

The description is three sentences and front-loaded with the core action. The third sentence is long and partly duplicates the schema's folder_id description, but it consolidates the ID-source workflow and the human-name warning into one place. Overall it is dense without being bloated.

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?

With only 2 params, no output schema, and annotations covering the destructive and read-only profile, the description covers the key prerequisites and the most common failure mode (passing a human folder name). It does not mention account_id, but the schema fully handles that. It also doesn't explain what happens to folder contents, but that is arguably beyond what a delete invocation needs from the description.

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 baseline applies. The description repeats folder_id semantics already in the schema but adds a concise resolution path ('Obtain with: email_list_folders -> folder.id'). It stays silent on account_id, but the schema provides a detailed explanation of when and how to pass it. The description adds marginal value on top of the schema.

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 opens with a specific verb-resource statement: 'Delete one exact mailbox folder/label.' The qualifier 'one exact' and the focus on folder/label clearly distinguish it from sibling tools like email_trash (messages), email_delete_draft, and email_update_folder. It also signals that resolution is a separate concern, differentiating from email_resolve_folder.

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 description provides a clear prerequisite workflow: 'Resolve folder_id first and verify target.' It also gives a strong negative constraint: 'Never pass: human folder name such as Inbox when an ID is required.' While it doesn't explicitly name alternative tools or state when not to use this tool, the context of the email_* siblings and the ID-resolution guidance make usage conditions clear.

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