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

Goes well beyond the readOnly/idempotent annotations: discloses data sources (bytecode, storage slots, probe calls via free public RPCs), the full classification taxonomy, and the non-obvious billing behavior — $0.002 USDC via x402, with an unpaid call returning a PaymentRequired object that must be retried with params._meta['x402/payment']. That payment flow is critical operational context an agent cannot infer from annotations or schema.

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 purpose question, then structured as classification list → data sources → pricing/payment → HTTP endpoint. It is dense and semicolon-heavy, but nearly every clause carries real information; the HTTP endpoint line is the only borderline addition.

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?

There is no output schema, so the description must convey return semantics — and it does, enumerating every classification, proxy standard, implementation/admin fields, owner(), nonce, balance, and code size. Combined with the payment retry mechanics, an agent has everything needed to call and interpret results 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 coverage is 100%, so both parameters are already documented, including the chain default list. The description reinforces that results are per-chain ('on each chain') but adds no format or syntax detail for the chain parameter beyond the schema. Baseline 3 is appropriate.

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?

Opens with the exact question the tool answers ('What is this address on each chain') and enumerates the concrete classifications it returns (EOA types, token standards, Safe multisig, proxy patterns). This is unmistakable and easily distinguished from siblings like token_info, wallet_snapshot, or tx_decode.

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?

Frames clear usage context by stating the question it answers and the per-chain scope, which implies when an agent should reach for it (address classification/inspection). It does not explicitly name alternatives or exclusions (e.g., 'use token_info for token metadata instead'), so it falls short of a 5.

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