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

Beyond the destructiveHint annotation, the description details refusal conditions, the permanent nature of deletion (no Trash recovery), and the expected response behavior (read refusal and tell the user). This fully discloses the tool's edge-case behavior and consequences.

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 somewhat verbose but every sentence adds critical operational detail (refusal cases, recovery guidance, system folder exclusions). The structure flows logically from action to constraints to fallback instructions, making it efficient despite its length.

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?

Given the tool's destructive nature and multiple refusal scenarios, the description covers all relevant cases (non-empty, subfolders, INBOX, system folders) and provides clear next steps. It even specifies how to handle the output (read the refusal and tell the user), making it fully self-contained for an agent.

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?

The single parameter 'name' is fully described in the schema with an example ('Old projects'). The description adds no additional semantic information beyond what the schema already provides, so a baseline score of 3 is appropriate.

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?

Clearly states the tool deletes an empty folder and unsubscribes it, distinguishing it from delete_email by noting the lack of a Trash recovery option. The scope is specific and the resource (folder) is unambiguous.

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?

Explicitly instructs when to use this tool versus alternatives (move_email, delete_email) and warns about refusals for non-empty, subfoldered, or system folders. Tells the agent to read the refusal and relay it to the user, leaving no ambiguity about proper usage.

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