Remove labels from a message

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

Annotations already declare idempotentHint=true, readOnlyHint=false, and destructiveHint=false, so the description doesn't need to restate these. However, the description adds no additional behavioral context, such as whether removing labels is reversible or what happens to the message if all labels are removed. Given the annotations cover the core safety profile, the description is adequate but not helpful beyond the basic action.

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, clear sentence with no unnecessary words. It is front-loaded with the key action and resource. Every word adds value, and it is appropriately concise for a simple operation.

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 that the schema covers all parameters and annotations provide basic behavioral hints, the description is sufficient for a simple removal tool. However, it lacks any mention of return values, error conditions (e.g., if the message or labels don't exist), or side effects. For an idempotent operation, this is acceptable but not complete.

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 input schema has 100% description coverage for all three parameters, including format and constraints. The description ('Remove one or more labels') does not add any new meaning beyond what the schema provides. A baseline score of 3 is appropriate since the schema already documents the parameters thoroughly.

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 action ('Remove') and the resource ('labels from a single Gmail message'). It specifies that multiple labels can be removed. However, it does not explicitly differentiate from the sibling tool 'unlabel_thread', which performs a similar operation on threads. The distinction is implied by mentioning 'message' rather than 'thread', but could be more explicit.

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?

No guidance is provided on when to use this tool versus alternatives like 'label_message' or 'unlabel_thread'. There is no mention of prerequisites, such as needing the user's consent or requiring certain labels to exist. The description offers no context about the results of removing labels (e.g., does it archive the message?).

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