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

Annotations already declare read-only, idempotent, and non-destructive behavior. The description adds the context that it deals with user preferences (language, currency, etc.), which is useful but does not elaborate on side effects, error conditions, or return specifics. This adds some context beyond the 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 a single, short sentence that efficiently communicates the core subject. It is free of unnecessary details and well-sized for the tool's simplicity.

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 description mentions user preferences but does not clarify what the tool returns (e.g., a list of settings, values for language/currency). Since there is no output schema, the description should explain the outcome, but it remains vague. It lacks completeness for a read-only tool.

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?

There are no parameters in the schema, so the description does not need to explain any. The empty schema has full coverage, and the description adds no parameter-related information. Baseline score of 3 is appropriate.

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 indicates the tool relates to user preferences, but it is phrased as a noun phrase rather than an action. It is unclear whether the tool retrieves, updates, or manages preferences. This provides some clarity but lacks a clear verb and explicit scope.

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 gives no guidance on when to use this tool compared to others. It does not mention typical scenarios, alternatives, or prerequisites. Usage instructions are entirely absent.

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