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

Annotations already declare destructiveHint=true, and the description adds substantial value beyond them: it explains exactly what is destroyed per provider – Gmail label removed from every message, Outlook category removed from the list, IMAP folder deleted only if empty. This is exactly the kind of consequence detail an agent needs before invoking a destructive tool.

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 core action and id source are front-loaded, and the long second sentence earns its length by covering three distinct provider behaviors. Phrasing around the IMAP case ('deletes only a folder holding no mail and no folder') is slightly convoluted but not wasteful.

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 tool with an output schema and safe/destructive annotations, the description covers the essential behavioral consequences that annotations cannot express. It stops short of noting error conditions or whether deleting an in-use label is recoverable, but it is otherwise complete enough to call correctly.

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 both parameters (id, mailbox) are already documented in the schema, and the description largely restates the id source. It adds a little provider-dependent meaning to mailbox but no syntax or format detail beyond the schema, so baseline 3 applies.

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 a specific verb and resource (delete one label) and ties the id to its source (labels_list), which distinguishes it cleanly from labels_update, labels_create, and labels_list. An agent can tell what this does and where the argument comes from without opening the schema.

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?

Names the prerequisite clearly (id from labels_list) and describes the operational context (no message is deleted), but gives no explicit when-not-to-use guidance or comparison against labels_update as the non-destructive alternative. Usage is clear but not fully routed.

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