gmail_apply_labels

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

With no annotations provided, the description carries full burden but offers minimal behavioral insight. It implies a write operation ('apply labels') but doesn't disclose critical traits: whether this modifies messages permanently, requires specific Gmail permissions, has rate limits, returns confirmation, or handles errors. The description adds little value beyond the obvious 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, front-loaded sentence with zero wasted words. It efficiently conveys the core action without unnecessary elaboration, making it easy to parse quickly. This is appropriately sized for a straightforward tool.

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 complexity (a mutation with 4 parameters, 0% schema coverage, no annotations, but with an output schema), the description is inadequate. It doesn't explain the mutation's impact, parameter interactions, or what the output schema might contain. The presence of an output schema reduces the need to describe return values, but the description still lacks essential context for safe and effective use.

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 0%, so the description must compensate but fails to do so. It mentions 'labels' and 'messages' vaguely, without explaining parameter roles (e.g., 'labels' as an array of label IDs/names, 'message_id' vs 'message_ids' for single vs batch operations, or 'approval_id' for async processes). The description adds almost no meaning beyond the parameter names visible in the schema.

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 verb ('apply') and resource ('labels to one or more messages'), making the purpose immediately understandable. However, it doesn't differentiate this tool from potential sibling operations like 'gmail_remove_labels' or 'gmail_modify_labels' (though none exist in the provided sibling list), so it doesn't reach the highest specificity level.

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 no guidance on when to use this tool versus alternatives. It doesn't mention prerequisites (e.g., needing existing labels or message access), exclusions, or related tools like 'gmail_get_message' for verification. The agent must infer usage from the tool name and parameters alone.

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