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

With no annotations, the description carries the full burden and does a good job: it discloses the underlying method (eth_getCode), the nature of the result (contract vs wallet plus bytecode size), and cost/payment model ($0.005 per call over x402/USDC). It omits read-only framing, latency, and failure behavior, so not a 5, but far above baseline.

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 sentences, tightly front-loaded: what it returns first, then the use case, then the mechanism and price. Every sentence adds information with no waste.

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?

There is no output schema, so the description must describe returns, and it does ('contract or wallet' and bytecode size). Pricing and payment rails are also given, leaving nothing an agent needs before invoking it.

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 the address and chain parameters. The description adds the eth_getCode reference but no syntax, format, or chain-default guidance, so the 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?

States a precise verb+resource: determines whether an address is a contract or a plain wallet and how large its bytecode is. This is clearly distinguishable from siblings like evm_balance, evm_call, or evm_token_safety without opening any 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 a concrete when-to-use: 'a cheap safety check before sending funds,' which frames the intent well. It does not explicitly name an alternative tool or state exclusions, so it falls short of a full 5.

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