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

Annotations already declare readOnlyHint=true, destructiveHint=false, and openWorldHint=true, but the description adds meaningful behavior beyond them: 400/404 error semantics, that failed calls are uncharged, pricing at $0.01/call, first 25 free, and that repeated calls are charged and therefore not free. It also clarifies that the tool only reads/computes and changes nothing, consistent with 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?

The purpose and detection standards are front-loaded, followed by usage guidance, error behavior, and cost details. It is dense and slightly overpacked with billing/free-tier information, but each clause carries relevant operational context rather than 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?

For a one-parameter read-only tool with annotations and no output schema, the description covers what is detected, when to use it, the sibling alternative, error cases, and cost behavior. Nothing critical needed to invoke it correctly appears to be 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% and the single address parameter is documented as a '0x contract address.' The description adds an example address and states the malformed-address behavior (400), which gives useful format guidance beyond the schema without being essential.

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 verb and resource: 'Find the implementation behind a proxy contract on Sonic.' It goes further by listing the exact proxy standards detected (EIP-1967, EIP-1822/UUPS, older OpenZeppelin, EIP-1167) and noting that it names the kind found, which clearly differentiates it from generic call/storage siblings.

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?

Explicitly says when to use it ('before trusting or decoding a contract whose code can be swapped by its admin') and names the alternative for a broader assessment ('for a fuller risk verdict use contract_risk'). The routing condition is clear and actionable.

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