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

Annotations already cover the safety profile (readOnlyHint, destructiveHint=false, openWorldHint). The description adds genuinely non-obvious context: that the value is contract-reported and not audited circulation, and that the call costs $0.005 USDC via x402. The payment requirement is a meaningful behavioral trait not present in the annotations.

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?

Three short sentences, front-loaded with what the tool returns, followed by the data-quality caveat and the cost. Every sentence carries distinct information and nothing is repeated from the schema.

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-only tool with no output schema, the description supplies purpose, a data-trust caveat, and a payment requirement — enough for correct invocation. It does not describe the returned representation or error behavior, but those gaps are minor here.

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 100% for the single 'token' parameter, including its address pattern, so the schema carries the semantic burden and baseline 3 applies. The description only loosely echoes the resource ('ERC-20 or ERC-721 contract'), adding no format or interpretation detail beyond 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?

The description states a specific verb and resource — checking a Base ERC-20/ERC-721 contract's total supply — which is clearly narrower than siblings like base_contract_info or base_erc20_balance. However, it does not explicitly name an alternative tool, so the differentiation from siblings is implied rather than stated.

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?

Usage is only implied by the verb 'Check' — the agent can infer this is the read path for supply. There is no guidance on when to prefer this over base_contract_info (which may also expose supply) or any exclusion conditions, leaving the selection decision to inference.

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