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

Annotations already declare readOnlyHint and openWorldHint, so safety is covered. The description adds genuinely new context by disclosing the paid access model ($0.002 USDC on Base via x402), which is behaviorally important, but it says nothing about failure modes (e.g., non-ERC-20 addresses) or how the payment flow is triggered.

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 compact sentences with zero filler, and the returned fields are front-loaded before the payment note. Every sentence carries information the agent needs.

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 competently compensates by listing the return fields, and it flags the paid access model. Remaining gaps are minor: it does not say what happens for non-ERC-20 or wrong-chain inputs, but for a single-address read tool this is close to complete.

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 description coverage is 0% for the single 'token' parameter, whose only documentation is a hex-address regex. The description's mention of 'ERC-20 metadata' loosely implies the parameter is an ERC-20 token address, adding marginal meaning, but it never states this explicitly.

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 the resource (ERC-20 metadata on Base) and enumerates the exact fields returned (name, symbol, decimals, total supply), which clearly separates it from siblings like base_erc20_balance, base_price, and base_token_risk. It lacks an explicit verb, but the purpose is unambiguous.

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?

There is no guidance on when to use this tool versus alternatives such as base_erc20_balance (balances) or base_price (pricing), nor any prerequisites or exclusions. The agent must infer usage entirely from the field list and sibling names.

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