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

Goes well beyond the readOnly/openWorld/idempotent annotations: one multicall execution, contract-code existence check, 404 is not charged, x402 USDC payment on Base at $0.001 per successful call, and the pay-without-payment flow returns a PaymentRequired object. That is unusually rich operational context.

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 trigger condition and the returned fields before moving to pricing mechanics. Three dense sentences with little waste, though the payment clause is packed and slows the read slightly.

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?

With no output schema, the description compensates by enumerating return fields (name, symbol, decimals, totalSupply, optional Chainlink USD price). Between that, the failure mode (404), and the payment flow, an agent has everything needed to invoke 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 coverage is 100% and both parameters are described in the schema, so baseline is 3. The description reinforces that the address is a token contract and that chain is Base or Ethereum, but adds no format, validation, or edge-case detail beyond the enum already in the schema.

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 — reads name, symbol, decimals and totalSupply from a token contract — and enumerates the exact fields returned. It also differentiates from the sibling price/dex_price tools by noting it only 'adds a Chainlink USD price when one exists for the symbol.'

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?

'Use when you have a token contract address and need to know what it is' gives an explicit trigger condition, and the 404-when-not-a-token note clarifies when the tool will not answer. It never names an alternative sibling for the price-lookup case, so routing is implied rather than stated.

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