get_rest_advisor

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

Annotations already convey read-only, idempotent, and non-destructive behavior, so the description need not repeat these. It does add the context of EU hours-of-service style, which hints at the regulatory framework behind the guidance. However, it does not disclose any edge cases, data availability limits, or the nature of the output beyond 'guidance.' Given the low complexity and strong annotations, this is adequate but not exceptional.

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 with no filler. It states the core purpose ('Fatigue guidance') first, then clarifies the basis ('continuous driving time') and adds a contextual qualifier ('EU hours-of-service style'). Every word earns its place, and it is appropriately sized for a zero-parameter tool.

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 tool has no parameters and an output schema exists (which we don't see but is present), the description sufficiently conveys what the tool does. It could be enhanced by explicitly stating when to call it (e.g., 'Use when the driver has been driving for a sustained period'), but it is currently adequate for an agent to understand its role among the sibling tools. The lack of any handling instructions for missing or invalid data is a minor gap.

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?

With zero parameters, the baseline is 4 per the rubric. The description's mention of 'continuous driving time' clarifies the conceptual input even though no explicit parameter exists, helping the agent understand what data drives the guidance. This adds value beyond the empty 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 clearly states a specific verb ('get') and resource ('rest advisor') with a precise function: providing fatigue guidance based on continuous driving time. It is distinct from sibling tools such as get_truck_state, get_navigation, and get_eco_score, which cover unrelated domains. The EU hours-of-service mention adds domain context without ambiguity.

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 the tool is relevant when continuous driving time is a factor, but it does not explicitly state when to use it versus alternatives, nor does it mention exclusion criteria. Since no sibling tool provides fatigue guidance, the lack of explicit alternatives is acceptable, but it still lacks a clear 'use when' statement. The phrase 'based on continuous driving time' gives an implicit trigger, but more explicit guidance would improve clarity.

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