gmail_modify

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

With no annotations, the description carries the full burden for behavioral disclosure. It states the action (modify labels) but does not mention that removing labels can be destructive, whether custom labels are supported, how the system labels behave (e.g., UNREAD is a label), or any side effects. This is a significant gap for a mutation tool.

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 that directly states the tool's purpose and includes a compact list of system labels. It is appropriately concise with no redundant information, though some might argue it could benefit from a brief usage example.

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 and the schema covers parameters, but the description lacks guidance on usage relative to siblings, behavioral caveats, and return value details. For a mutation tool with no annotations and no output schema, the description is minimally viable but leaves gaps in context.

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 fully documents all three parameters (messageId, addLabelIds, removeLabelIds), and the description adds value by enumerating the system label identifiers (INBOX, SPAM, TRASH, UNREAD, STARRED, IMPORTANT) that are valid values, which the schema does not specify. This enriches the parameter semantics beyond the baseline.

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 'Modify a Gmail message's labels' with a specific verb and resource. It lists system labels, and the singular 'a Gmail message' distinguishes it from gmail_batchModify and gmail_modifyThread, though it doesn't explicitly name these alternatives.

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 gmail_batchModify or gmail_modifyThread. The description only explains the basic operation and lists system labels, with no context on scope (single message vs batch/thread) or prerequisites.

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