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

Beyond the readOnly/non-destructive annotations, the description discloses concrete behavioral traits: malformed address returns 400, no-code address returns 404, failed calls are free, calls are charged and not idempotent in cost terms, and pricing details. It also explicitly says the tool reads/computes only and changes nothing.

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, then usage guidance, error behavior, an example, and pricing. Sentences are dense but each carries useful operational information for a paid read-only proxy tool.

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 one-parameter tool with annotations and no output schema, it is nearly complete: it explains what is inspected, what kind of result is named, error behavior, and cost. It could more explicitly describe the return structure, such as whether implementation, admin, and beacon values are always included, but the essential contract is clear.

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?

The single address parameter is fully documented by the schema, so baseline is 3. The description adds a concrete example address and ties malformed input to a 400 response, improving meaningfulness beyond the schema text.

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 specific verb and resource: find the implementation behind a proxy contract on Avalanche. It lists the exact mechanisms read (EIP-1967, beacon/admin slots, UUPS, OpenZeppelin layout, EIP-1167) and says it names the kind found, which clearly distinguishes it from generic storage or call tools.

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?

It gives explicit usage context: use before trusting or decoding upgradeable contracts, and directs agents to contract_risk for a fuller risk verdict. This names both when to use it and the main alternative.

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