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

With no annotations, the description carries the burden and does deliver real behavioral detail: exact integer maths, no floating point, no silent rounding, plus the $0.005 per-call cost and x402/USDC payment requirement. It omits error behavior and output format, which keeps it from a 5.

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 core purpose is front-loaded in the first sentence, followed by two sentences on precision and cost. Slight marketing flavor ('The mistake that costs real money') but each sentence carries usable information.

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?

No output schema and no annotations exist, so the description should explain the return shape (e.g., that it returns a string), which it does not. It does cover precision guarantees and pricing, partially compensating for the missing structured metadata.

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?

Schema description coverage is 100%, so the schema already documents amount/from/to, and the baseline is 3. The description echoes that accepted units include token decimals, adding only marginal meaning 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?

States a specific verb (Converts) plus the exact resource scope (wei, gwei, ether, any token decimals), which no sibling tool covers. An agent can immediately distinguish it from the evm_* and other util_* tools.

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 when the tool is useful (unit conversion) but gives no explicit when-to-use vs alternatives, no prerequisites, and never references related siblings like evm_balance or evm_token_price where a value might be converted. Usage is inferable but not stated.

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