listGmailLabels

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

No annotations are provided, so the description carries the full burden of behavioral disclosure. It indicates the operation is a read (retrieves) and mentions system and custom labels, but it does not disclose authentication requirements, rate limits, or detailed return structure.

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 a single, well-structured sentence that is front-loaded with the action. Every word contributes to understanding, with no redundant or extraneous information.

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 zero-parameter, list-all tool with no output schema, the description sufficiently conveys the tool's function and result scope. It could mention that returns label objects (e.g., id, name), but that is not critical for an agent to decide when to use it.

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 tool has zero parameters, and the description adds contextual value by specifying that the list includes system labels like Inbox/Sent/Draft and custom labels. This goes beyond the empty schema, though it does not elaborate on label metadata format.

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 retrieves all labels in the user's Gmail account, with a specific verb ('retrieves') and resource ('labels'). It distinguishes from sibling Gmail tools by focusing on labels rather than threads, messages, or drafts.

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 clear context that this is the tool for listing Gmail labels, but it does not explicitly mention alternatives or when not to use it. The purpose is obvious enough that an agent can infer when to invoke it.

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