gmail_modify_labels

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

With no annotations provided, the description carries the behavioral transparency burden. It discloses that full scope is required, which is useful. However, it does not disclose potential side effects, what happens when both add and remove are specified, or whether the operation is idempotent. The description is not misleading, but it lacks depth.

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 two concise sentences, front-loaded with the core action, and provides an efficient example. No fluff. It fully earns its place.

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?

The tool is relatively simple with 4 parameters and no output schema. The description covers the main action and scope, but it omits context such as the relationship to batch operations, behavior when no label IDs are provided, or typical use cases. It is adequate but not fully complete for guiding an agent.

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 coverage is 100% with each parameter described. The description adds examples (e.g., 'INBOX', 'STARRED') and clarifies the use of label IDs, which reinforces the schema but does not add substantial new meaning. It meets the baseline for high schema coverage.

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 tool's function: adding or removing labels from a Gmail message. It uses a specific verb ('Add or remove') and resource ('labels from a Gmail message'). While it doesn't explicitly distinguish itself from sibling gmail_batch_modify_labels, the singular 'a Gmail message' implies single-message scope, which differentiates it from the batch variant.

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 implies usage for modifying labels on a single message and tells the agent to use label IDs, but it does not explicitly state when to use this tool instead of alternatives like gmail_batch_modify_labels or gmail_archive. The scope requirement is mentioned, but no clear exclusion criteria or alternative tool references are provided.

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