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

No annotations exist, so the description must carry the behavioral burden, and it does disclose real behavior: the source chain (Blockscout with Sourcify fallback) and the payment/trial constraint of 5 free calls per signed wallet. It stops short of saying what happens for unverified contracts, whether calls fail or return a status field, or what the response looks like.

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?

One compact sentence with the resource and returned fields front-loaded, followed by the source and pricing note. The middle field enumeration is dense but every item is informative; nothing is filler.

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 usefully enumerates returned fields, and it flags the pricing model. But for a 3-parameter tool with zero schema documentation and no annotations, it leaves the address-vs-contract input distinction and chain value format unresolved.

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 all three parameters (chain, address, contract), so the description carries the full burden and does not meet it. It never explains accepted chain identifiers or why both 'address' and 'contract' exist as separate inputs, leaving an ambiguous choice the agent must guess at.

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 resource (contract) and the exact data it returns (compiler version, language, license, license, proxy type), which is far more informative than a bare name. However, it does not distinguish itself from nearby siblings like x402-contract-triage, x402-event-decode, or x402-event-decode/x402-bytecode which also inspect contracts.

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 when-to-use guidance, no prerequisites, and no named alternative tool for related tasks (e.g., contract triage, ABI lookup, proxy detection). The agent must infer the usage context from the field list alone.

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