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

With no annotations, the description carries the full burden of behavioral disclosure. It adds valuable context beyond the basic function by stating update frequency ('Updated daily'), defining the trend and comparison outputs, and explaining the practical significance. It does not mention error handling or data source limitations, but for a simple read-only lookup, the provided transparency is solid.

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 concise: two sentences with the functional details front-loaded. The second sentence adds contextual value about why gas storage matters, without unnecessary fluff. Every sentence contributes to understanding the 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 low complexity (one parameter, no output schema), the description is largely complete: it explains the core purpose, the outputs (percentage, trend, comparison, risk signal), and update frequency. A minor gap is the lack of explicit output format, but for a simple retrieval tool, the description provides sufficient context for an agent to invoke it effectively.

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 schema already fully describes the sole parameter 'country' (ISO2 code, EU requirement), so the description adds no additional parameter-level guidance. Per the rubric, high schema coverage yields a baseline score of 3, and the description does not go 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 clearly states the tool's function with a specific verb ('Get') and resource ('current natural gas storage level for any EU country'), and details the key outputs (percentage, trend, 5-year comparison, risk signal). It is easily distinguished from sibling tools, which focus on prices, carbon, and weather rather than gas storage.

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 provides clear context for when this tool would be useful, specifically linking gas storage levels to electricity prices. It does not explicitly name alternatives or exclusions, but the context is sufficient for an agent to understand its role among the sibling price and carbon tools.

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