Get Current Labels on a Gmail Message

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

Annotations already declare readOnlyHint=true and idempotentHint=true, establishing the safety profile. The description adds return details (subject, snippet, label IDs) and example queries, providing extra behavioral context without contradicting annotations.

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 compact and well-structured: purpose, args, returns, and examples in a few lines. Every sentence adds value, with no redundancy or filler.

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 single-parameter read-only retrieval tool, the description is complete. Annotations cover safety, schema covers the parameter, and the description provides return type and use cases. No output schema exists, but the return description compensates sufficiently.

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 parameter message_id is self-explanatory. The description repeats the parameter but does not add new semantic meaning, 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 'Retrieve' with a clear resource 'labels on a specific Gmail message.' The examples further clarify the scope, distinguishing this from sibling tools like gmail_list_labels (all labels) and gmail_modify_message_labels (changing labels).

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?

Two concrete 'Use when' examples provide clear scenarios for invocation. However, it lacks explicit 'when not to use' guidance or alternative tool mentions, such as when to use gmail_list_labels for global label listing.

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