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

Annotations already declare readOnlyHint and openWorldHint, so the safety profile is covered. The description adds genuinely new behavioral facts: the operation is restricted to the Base chain, it is metered at 0.0030 USDC per call with the first call free, and it deliberately omits risk analysis. That cost and chain-scoping detail goes beyond the structured fields.

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?

Three tightly packed sentences, zero filler, scope constraint and exclusion front-loaded before the alternatives and pricing. Every clause carries either capability, routing, or cost information.

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?

No output schema exists, yet the description enumerates the returned fields, states the chain, discloses pricing, and routes to alternatives. For a one-parameter read tool that is everything an agent needs to invoke it 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 there is a single required address parameter, so the schema carries the load. The description only adds chain context ('any address on Base'), which is marginal over what the schema provides. Baseline 3 applies.

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 structure) and enumerates the exact outputs: bytecode size, EIP-1167/EIP-1967 proxy detection with implementation and admin, and owner(). It scopes itself with 'ONLY' and names the two sibling tools it is not, so an agent can separate it from token-due-diligence and contract-read without opening a schema.

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 explicit negative guidance ('NOT a security audit') plus two named alternatives with the condition that selects each: token-due-diligence for risk flags and pool liquidity, contract-read for arbitrary view functions. The agent knows both when to use this tool and when to route elsewhere.

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