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

Annotations only declare readOnly/openWorld/idempotent; the description adds the decisive behavior the agent cannot infer: cost ($0.003 USDC on Base), the x402 flow (unpaid call returns PaymentRequired, retry via params._meta["x402/payment"]), and the equivalent HTTP endpoint. It also discloses the account-type taxonomy including EIP-7702 delegated EOAs.

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?

Front-loaded with the payload and chains, then payment mechanics — every clause carries information with no filler. It is, however, one long run-on sentence, which makes the payment instructions harder to parse than a short structured break would.

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, so the description must describe returns — it does, itemizing every field plus totals and active-chain summary. Combined with the payment/transport details, an agent has everything needed to call it and handle the paid re-try 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?

Only one parameter, and the schema already documents it as a '0x EVM address' at 100% coverage. The description adds no format, checksum, or validation detail beyond the schema, so 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 concrete resource (wallet snapshot) and enumerates exactly what is returned — native balance, USDC/USDT balances, nonce, account type — across eight named chains. This clearly separates it from single-chain siblings such as address_info, token_balances and token_transfers without the agent needing to open any 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?

The opening 'One call, 8 chains' implies the use case (consolidated multi-chain portfolio view) and implicitly contrasts with per-chain calls. It does not name an alternative sibling or state when not to use it, so it stops short of full routing guidance.

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