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

Annotations already declare readOnly, idempotent, openWorld and non-destructive, but the description adds materially more: the x402 payment flow, the $0.01 USDC cost, the PaymentRequired result and retry mechanism, the no-approval authorization, the no-charge-on-failure policy, and the fact that bad input is rejected before charging. These are behaviors an agent cannot infer from annotations alone.

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 key trigger condition is front-loaded, and the payload details are packed into dense but purposeful sentences. The payment and x402 mechanics are necessarily verbose, but the description remains well-organized and mostly free of waste.

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 takes responsibility for enumerating the returned facts (code size, EIP-7702 delegation, name, symbol, decimals, supply, proxy/admin, owner, privileged functions), and it fully explains the payment/retry behavior. An agent has everything needed to call this correctly and understand the response.

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?

There is one parameter and schema description coverage is 100%, so the schema already defines the address argument. The description does not add format, validation, or semantic detail about the address parameter beyond what the schema provides; 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 specific verb and resource: it returns contract facts (code size, delegation, token metadata, privileges) for a Base ERC-20. That is far more specific than the tool name, but it never names or distinguishes itself from the sibling tools (presign_check, screen_text), so it stops short of a 5.

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?

"Call before your agent approves, receives or sends a Base ERC-20" gives an explicit trigger condition. It also frames the scope as "facts only: no grades, not investment advice." There are no named alternatives or explicit exclusions, so it is clear context without full when-not guidance.

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