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

With no annotations provided, the description carries the full burden for behavioral disclosure. It indicates the data is 'Current' and cost estimates are 'estimates', which hints at approximation, but it does not mention read-only nature, update frequency, or potential sources of data. For a simple read operation, this is minimally adequate but not rich.

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, concise sentence that clearly states the tool's output without unnecessary words. It is front-loaded and every word serves a purpose.

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's simplicity (no parameters, no nested objects, no output schema), the description provides sufficient context by naming the resource (Arbitrum gas prices) and the specific outputs (USD cost estimates for transfers and swaps). It does not specify live data freshness or exact units, but for a gas tracking tool, this is adequate.

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 tool has zero parameters, so there is nothing to explain. The description correctly does not mention parameters, and the baseline of 4 is appropriate given the schema coverage is 100% and no parameters exist.

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 identifies the tool's purpose: providing current Arbitrum gas prices with USD cost estimates for transfers and swaps. It distinguishes this tool from the sibling tools, which focus on other topics like DeFi yields, token risk, and whale watching, though it lacks an explicit verb like 'fetch' or 'display'.

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 no guidance on when to use this tool versus alternatives. It does not mention any exclusions, prerequisites, or specific use cases beyond the general statement of gas prices. Given the sibling tools cover different domains, some differentiation is implied, but the description does not explicitly state it.

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