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

The description resolves the unusual readOnlyHint=false by explaining 'not marked read-only because each call is charged,' and adds pricing, free-call and 422 error behavior — genuinely beyond annotations. However, openWorldHint and idempotentHint are left unexplained and no return-format detail is given, so it is solid but not exhaustive.

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-loads purpose and the sibling alternative before input, example and pricing. All sentences carry weight, though the pricing/credits clause adds some density to an otherwise tight definition.

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 what is returned, the input format, an example, error behavior and cost. An agent has everything needed to call 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%, so the baseline is 3, but the description adds a concrete example address and the semantics that a non-ERC-20 address returns 422 uncharged. That goes beyond the schema's bare '0x ERC-20 token contract 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 verb (look up) and a precise resource set (name, symbol, decimals, total supply of an ERC-20 token), scoped to Arbitrum One and read live from the contract. It distinguishes itself from the sibling arb_token_balance by explicitly routing holder balances elsewhere.

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?

Gives explicit use cases ('identify an unknown token address or format raw amounts') and names the alternative for a different need ('for a holder's balance use arb_token_balance'). The when-not condition is concrete.

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