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

With no annotations, the description carries the full burden and does disclose two material traits: it is a read against live public RPC, and it is a paid call (0.01 USDC via x402, 12 sats Cashu NUT-24, 12 sats L402) — payment requirements an agent must know before invoking. It does not disclose failure behavior for addresses lacking contract code or non-ERC-20 contracts, which it hints at but never resolves.

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?

Three dense sentences with no filler: the resource and return fields come first, RPC sourcing second, payment terms last. The pricing sentence is long but every clause is operationally relevant to an agent that must pay. Slightly more compact phrasing of the three payment rails would reach 5.

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 and no annotations, so the description has to cover both the return payload (it does, field by field) and the safety/payment profile (it does: read-only, live RPC, priced). The remaining hole is address formatting and error behavior, which matters for a 2-param paid tool but is not fatal.

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 0% and there are 2 parameters, so the description must compensate. It does list five accepted chain values (base, ethereum, arbitrum, optimism, polygon), effectively supplying the missing enum for `chain`. However, `address` is left entirely unspecified in both schema and description — no format, hex/checksum, or contract-vs-EOA semantics — so compensation is only partial.

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?

The description names a specific resource (ERC-20 token facts for a contract) and enumerates exactly what is returned: name, symbol, decimals, total supply, and a contract-code check. That field list implicitly separates it from siblings like evm_balance, evm_gas, and evm_tx, which return different data. It never explicitly names a sibling, so it lands just short of a 5.

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?

Usage is only implied: the agent can infer this is the tool for token metadata given a contract address, and the parenthetical chain list and price options give practical context. There is no statement of when to prefer this over evm_balance/evm_tx, nor any exclusion (e.g., what happens for non-token contracts or EOAs).

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