gmail_labels

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

No annotations are provided, so the description must carry the burden. 'List' plus 'available to' implies a safe read operation, and the parenthetical discloses that system folders are included, but nothing is said about return shape, whether system labels are flagged distinctly, or whether hidden/unsubscribed labels appear.

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?

A single sentence with no filler; the resource comes first and the downstream consumers are tucked into a compact prepositional phrase.

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 no output schema and no parameters, the description covers the essentials: what is listed and what it is for. The only gap is that the exact returned shape (name vs. id, how system folders are marked) remains unspecified.

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 takes zero parameters, so the baseline of 4 applies. The description correctly implies no input is needed to fetch the full label set.

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 ('List the user labels (and system folders)') and ties the output to its consumers, gmail.label and gmail.move. An agent can tell it is a read-only enumeration tool, though the description does not distinguish it from the sibling gmail_folders, which sounds overlapping.

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?

Usage is implied through 'available to gmail.label / gmail.move', which hints you call this before labeling or moving messages. There is no explicit when-to-use/when-not-to-use statement and no guidance on choosing between this and gmail_folders.

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