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

Annotations already declare readOnlyHint, openWorldHint, idempotentHint, and destructiveHint=false, so the safety profile is covered. The description adds valuable behavioral context: the $0.001 USDC cost, the list of supported chains, and the fact that it is byte-identical to a specific GET endpoint. This goes beyond annotation coverage and gives the agent practical operational knowledge. No contradiction with annotations.

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 compact yet information-dense: definition, use case, cost, chains, and API equivalence all in a few sentences. The first sentence front-loads the core concept (fingerprint), and every clause serves a purpose. No filler or repetition.

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 an output schema present, return format is handled externally. Annotations cover safety and idempotence. The description covers use case, cost, supported chains, and a REST equivalence reference. An agent has everything needed to decide when to use this tool and how to invoke it correctly. Complete within its scope.

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% for both parameters (chain lists allowed values, address specifies 0x + 40 hex). The description reinforces the chain list and provides a concrete example address in the URL, but adds little semantic nuance beyond the schema. Baseline 3 is appropriate since the schema fully documents parameters.

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 states a clear verb (fingerprint) and resource (contract's bytecode), and defines exactly what the tool computes: SHA-256 of deployed bytecode plus size and edges. It explicitly explains the semantic meaning (same fingerprint = same compiled contract) and the use case (detecting clones of known scams), distinguishing it from sibling tools like chain_code, chain_code_at, and chain_bytecode_capabilities. The purpose is unmistakable.

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 a concrete usage scenario: detecting clones of known scams before interaction. It also provides operational constraints (cost per call, supported chains) and references a REST endpoint equivalence. It does not explicitly state when NOT to use it or compare with alternative tools, which would have made it a 5, but the context clearly implies its intended use case.

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