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

Annotations already flag a non-read-only, open-world, non-idempotent call, and the description usefully adds the $0.05 USDC cost, the credit-key payment path, and the unpaid fallback response. It still leaves open whether a failed check still consumes credit, what the neutral analysis contains, and any rate limits.

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 dense but well-ordered passage: cost first, then what is checked, then the payment/fallback condition. Every clause carries information an agent needs before calling.

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 carries the return-value burden and does so by naming the report contents and the unpaid alternative response. Adequate for a two-parameter paid tool, with only edge-case billing behavior left unstated.

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 both address and credit_key are already documented in the schema, including the pattern and the fallback behavior. The description adds no format or semantic detail beyond that baseline.

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 ('Contract check on Base') and enumerates exactly what is inspected: bytecode presence/size, Sourcify verification, EIP-1967 proxy/admin slots, implementation verification, plus a neutral analysis. The resource is clearly distinct from the token/wallet-oriented siblings, though no sibling is named explicitly.

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?

Gives concrete invocation guidance for the paid path: pass credit_key to pay from a prepaid key, otherwise the call returns price and payment options instead of a report. It does not say when to prefer this over kairos_token_check or kairos_wallet_profile, so routing between siblings is left to inference.

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