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

Annotations already declare readOnlyHint, openWorldHint, and idempotentHint=false; the description adds paid-call pricing ($0.002 via x402/card key, first 25 free), failed calls free, and explicitly that it changes nothing. 'Read live' signals freshness, but caching/refresh behavior and latency are not addressed.

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 purpose is front-loaded, but the text is a dense run-on that packs billing, example, and disclaimers together; the credits parenthetical and repeat-charge note could be trimmed without losing signal.

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?

Chain coverage, cost, and safety are all clear, but with no output schema it never hints at return shape (per-chain breakdown vs aggregated totals). That is a real gap for a tool whose value is its aggregated result.

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 coverage is 100% and already documents the single address parameter. The description adds a concrete example address and clarifies 'any EVM address', which usefully confirms the cross-chain expectation beyond '0x wallet address'.

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 resource and scope: native coin plus USDC totals for any EVM address across five named chains in one call. It contrasts with narrower siblings like eth_balance and eth_token_balance by making multi-chain aggregation explicit.

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?

Gives explicit when-to-use triggers ('before a payment', 'confirm funds arrived') and describes the multi-chain scope that distinguishes it from single-chain balance tools. Cost and free-tier guidance further support the decision to call it.

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