evm_balance

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

With no annotations, the description carries full disclosure and delivers: read-only access straight from chain, chain id 8453, per-call price ($0.002 USDC), and p99 latency (900ms). These cost/latency/authorization-relevant facts are exactly what an agent needs before invoking.

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?

One dense paragraph front-loads the resource and chain, then use cases, then param and cost/latency facts. Every clause earns its place; nothing is filler.

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 exists, and the description compensates by enumerating what is returned (ETH balance, USDC balance, transaction count, x402 call coverage). Combined with cost, latency, and chain context, an agent has everything needed to call it correctly.

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% with a single required param whose pattern is already documented in the schema. The description repeats 'address (required, 0x...)' without adding format or semantic meaning beyond that, so the baseline 3 applies.

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+resource (read ETH/USDC balance of any address on Base mainnet, chain 8453) and expands scope to tx count and x402 call coverage. An agent can distinguish it from evm_tx, wallet_portfolio, or erc20_transfers without opening the schema.

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 three concrete when-to-use scenarios (pre-paid-workflow self-check, counterparty payment verification, treasury monitoring), which is strong context. It stops short of naming an alternative tool or a when-not-to-use condition, so it does not reach the top band.

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