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

The description adds valuable context beyond annotations: it clarifies that deletion is permanent, specifies the effect on messages (label removal without message deletion), and notes restrictions on label types (user-created vs. system). While annotations indicate destructiveHint=true and readOnlyHint=false, the description enriches this with practical behavioral details, though it doesn't cover aspects like error handling or permissions.

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 highly concise and well-structured: three sentences that efficiently convey purpose, behavior, and usage constraints without redundancy. Each sentence adds critical information, making it front-loaded and easy to parse for an agent.

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 (destructive operation with restrictions), the description is complete: it covers the action, effects, limitations, and usage context. With annotations providing safety hints and an output schema likely handling return values, no significant gaps remain. It adequately prepares an agent for correct tool selection and invocation.

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?

With 100% schema description coverage, the schema already fully documents the single parameter (labelId). The description does not add any parameter-specific semantics beyond what's in the schema, such as format examples or validation rules. However, it implies the parameter must reference a deletable label, which aligns with the schema's guidance.

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 specific action ('permanently delete') and resource ('a Gmail label'), distinguishing it from siblings like 'remove_labels' (which removes labels from messages) and 'create_label'. It explicitly notes what happens to messages ('removes the label from all messages but does not delete the messages themselves'), avoiding confusion with message deletion tools.

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 explicit guidance on when to use this tool vs. alternatives: it specifies that only user-created labels can be deleted, while system labels (INBOX, SENT, etc.) cannot be removed. This clearly defines the scope and exclusions, helping the agent avoid incorrect invocations for system labels.

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