list_labels

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

No annotations are provided, so the description carries the burden. It discloses the return shape ('id and name') and 'List' implies a read-only operation, but it does not state whether system labels are included, how results are ordered, or any other behavioral traits. This is adequate but shallow for a tool with no annotation safety profile.

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 sentence with no filler. The action and resource are front-loaded, and the parenthetical about output fields provides useful specificity without adding 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?

For a simple one-parameter tool with no output schema, the description covers the essential information: what the tool does and what it returns. It omits minor details like whether system labels are included or whether pagination exists, but these are not critical for an agent deciding to invoke the tool.

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% and the only parameter 'account' is already described as the authorized Gmail account. The tool description adds no additional parameter semantics beyond implicitly tying the account to the labels being listed, so the baseline score of 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?

The description uses a specific verb ('List') and a specific resource ('account's labels'), plus the output fields ('id and name'). This clearly distinguishes it from sibling tools that operate on messages, drafts, filters, or accounts.

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 intended use is implied: when you need to list an account's labels. However, the description provides no explicit guidance on when to choose this tool over alternatives like list_filters or modify_labels, nor does it state any exclusions. The context is present but not elaborated.

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