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

Annotations already declare readOnlyHint=true and openWorldHint=true, so the safety profile is covered. The description adds genuinely useful non-annotation context: this call is paid, costing $0.01 USDC on Base via x402, which an agent needs before invoking. It stops short of describing failure modes (non-ERC-20 address, unverified contract) or any rate/limit behavior.

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?

Two sentences, zero filler. What the tool returns is front-loaded, and the payment detail follows as a distinct, necessary second fact.

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?

For a single-parameter read tool with no output schema, the description covers the returned fields, the chain, the token standard, the keying parameter, and the cost of the call. Only error/edge-case behavior is unstated, which is a minor gap at this complexity level.

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%, so the description carries the burden. It clarifies that the single 'token' parameter is a contract address on Base identifying an ERC-20, which adds semantic meaning beyond the bare 0x{40} pattern in the schema. It does not clarify what happens with a non-ERC-20 or EOA 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: ERC-20 token metadata on Base, keyed by contract address, and enumerates exactly what comes back (name, symbol, decimals, total supply). That field list implicitly separates it from siblings like base_token_risk (risk scoring) and base_erc20_balance (holder balance), so an agent can route without opening either 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 description makes the usage context clear (any ERC-20 on Base, addressed by contract address) but never states when to pick this over base_token_risk, base_erc20_balance, or base_contract, nor any preconditions. Usage is implied by the resource scope rather than stated, which is the definition of a 3.

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