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

Annotations already provide readOnlyHint=true, idempotentHint=true, and destructiveHint=false, so the safety profile is covered. The description adds valuable behavioral context beyond this: the exact JSON return fields, the unverified-contract case with verified=false, the API key requirement, and the open dataset origins. This combination gives an agent a solid mental model of the operation.

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 organized into short, focused sentences: what it returns, when to use it, when not to use it with alternatives, return format, edge case, and auth requirement. It is slightly dense but every clause carries information and there is no meaningful 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?

With no output schema, the description takes on the burden of explaining return values, and it does so explicitly including edge-case behavior for unverified contracts. Combined with annotations covering safety/idempotence and the small parameter set, nothing an agent needs to select and call this tool correctly 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 the schema already documents both parameters. The description adds a list of valid chains and reaffirms the address format, but does not add substantial new meaning beyond the schema. This matches the baseline 3 for full schema coverage.

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 identifies the resource (verified ABI of a contract), the data source (Sourcify), and the supported chains, which makes the tool's purpose unmistakable. It also differentiates itself from siblings by explicitly contrasting with decode_calldata and convert_evm.

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?

The description gives explicit when-to-use guidance ('Use it before calling or decoding a contract you do not have the ABI for') and explicit when-not-to-use guidance with named alternatives ('Not for decoding a specific calldata blob (use decode_calldata) ... not for a function selector (use convert_evm)'). No inference is required.

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