Change the display language in Gmail by specifying an RFC 3066 language tag to update account language settings.
Updates language settings
| Name | Required | Description | Default |
|---|---|---|---|
| displayLanguage | Yes | The language to display Gmail in, formatted as an RFC 3066 Language Tag |
Changes observed during successful MCP inspections.
v1.0.0Input schema / $schemaAdded value: +"http://json-schema.org/draft-07/schema#"Input schema / additionalPropertiesAdded value: +falseDoes the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Without annotations, the description must disclose behavioral traits. It only states 'updates' but does not mention whether the operation is reversible, requires authentication, or has side effects.
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 sentence that is front-loaded and concise. However, it could provide slightly more informative content without compromising brevity.
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 simplicity of the tool with one parameter and no output schema, the description is complete in a minimal sense but lacks context about the update behavior, default values, or what the response looks like.
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 has 100% coverage for the single parameter, including a description of the RFC 3066 Language Tag format. The tool description adds no additional meaning beyond 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 'Updates language settings' clearly indicates the action (update) and resource (language settings). It distinguishes from sibling tools like 'get_language' (read) and other update tools for different settings.
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, such as 'get_language' for reading or other update tools. No prerequisites or context for use are mentioned.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.