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

With no annotations provided, the description carries the full burden. It discloses a cost ($0.001 USDC via x402) and that data comes from a live RPC, which are useful behavioral traits. However, it does not mention error handling, rate limits, or the return type beyond 'wei'. For a simple getter, this is 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 two short sentences with no filler. The core action is front-loaded, and the cost note is appended as a practical detail. It is appropriately sized for a no-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 no output schema, the description should cover the return value. It specifies the unit (wei) and source (live RPC), which is sufficient for an agent to understand the result. It does not detail the exact data type (e.g., string vs number) or error scenarios, but for a simple gas price lookup, this is reasonably complete.

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 no parameters, so there is nothing to describe. Per the rubric, a zero-parameter tool gets a baseline of 4. The description adds no parameter information because none is needed.

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 action ('Return') and resource ('current Base gas price in wei from a live RPC'). It is unambiguous and distinct from sibling tools that deal with blocks, balances, or contracts. The addition of 'from a live RPC' adds specificity that differentiates it from any cached or historical gas price tool.

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 does not provide any guidance on when to use this tool versus alternatives or when not to use it. It only states the action and a cost. Since there are many sibling tools, explicit routing context would help, but none is given. The cost note is a practical detail but not usage guidance.

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