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

The description discloses that data is read live from the contract and states the exact cost ($0.001 in USDC via x402), which is critical behavioral context not covered by annotations. Annotations show readOnlyHint=false, but the description clarifies it is a read operation with a payment side effect. It does not detail error behavior or payment failure handling.

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 concise sentences: the first states what is returned and where it is read from; the second gives use cases and payment terms. No extraneous information, and the most important information is front-loaded.

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 purpose, usage, data source, and payment requirements. It could mention the return format (e.g., object with name, symbol, decimals, supply), but annotations and schema fill most gaps.

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 the single parameter is already described as a 0x ERC-20 token contract address. The description does not add format or validation details 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?

The description states a precise verb and resource: it returns name, symbol, decimals, and total supply of an ERC-20 token on Arbitrum One, read live from the contract. It is clearly distinguishable from sibling tools like arb_token_balance, which likely returns balances rather than metadata.

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 explicitly gives two use cases: identifying an unknown token address and formatting raw token amounts correctly. This tells the agent exactly when to use this tool rather than a balance or price tool.

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