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

Although annotations already declare readOnlyHint, openWorldHint, idempotentHint, and destructiveHint, the description adds substantial behavioral context: it queries Sourcify, can return full or partial matches, costs $0.02 per call over x402, supports a prepaid header for unlimited calls, and offers one free call per day. This exceeds what annotations alone provide.

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 front-loaded with the core purpose and then supplies pricing and authentication details in a readable sequence. It loses a point for redundancy: 'No API key required' appears twice in slightly different forms, and the pricing sentence is a bit dense.

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 simple one-parameter read-only lookup with an output schema present, the description fully covers input requirements, network, cost, authentication, and return-value characteristics. Nothing essential is missing for an agent to select and invoke this tool correctly.

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 only parameter, address, is already well documented as 'Contract address.' The description confirms address is required and implies it should be a Base contract address, but adds no format or validation details beyond the schema. 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 the specific action: checking Sourcify for a Base contract's verification status and returning the ABI as function/event name lists plus item count. This distinguishes it from sibling tools like contract_info or contract_danger by naming the data source and exact output shape.

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 provides clear usage context: the required address input, the base network, pricing, authentication options, and the fact that no API key or wallet is needed. It does not explicitly state when not to use this tool or name alternatives, but the guidance is unambiguous enough for an agent to route correctly.

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