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

With no annotations provided, the description carries the full burden. It discloses error handling ('An address with no code, or a contract that is not an ERC-20, is reported as such'), states it is NOT charged on such failures, and mentions the cost ($0.005 USDC per call via x402). This gives agents a clear picture of behavior and side effects.

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?

The description is a single paragraph that is efficient and front-loaded. It starts with the core purpose, then provides a compelling use case, then addresses edge cases and cost. Every sentence adds value with no redundancy.

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 tool with only 2 parameters and no output schema, the description covers purpose, usage context, error handling, and cost. It also mentions the chain selection and defaults. There is nothing an agent needs to know to call it correctly that is missing.

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%, so both parameters (address and chain) are already documented. The description adds no new semantic details beyond the schema, e.g., it doesn't explain chain defaults beyond what the schema already says. Baseline 3 is appropriate.

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 clearly states a specific verb ('Read') and resource ('an ERC-20's name, symbol, decimals and total supply') and adds the scope of confirming code presence. It distinguishes itself from siblings like address_info and tx_status by focusing on token metadata retrieval, making the purpose 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?

It provides a concrete use case: 'Use before quoting an amount or building a transfer' and explains the risk of getting decimals wrong. While it doesn't explicitly name alternatives, the context makes the appropriate invocation clear. The instruction to use it before quoting amounts is strong guidance.

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