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

With annotations already covering readOnly/destructive, the description adds real context: 400 for malformed address and 404 for codeless address are uncharged, costing is $0.01/call with 25 free and failed calls free, and it explains why idempotentHint=false ('each call is charged, so repeats are not free'). Only the shape of the returned data is left unspoken.

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?

Front-loaded with the capability, then usage, then failure modes, then pricing — good ordering. It is dense but every sentence (errors, price, 'failed calls free') carries decision-relevant information for an agent; the pricing tail runs a bit long.

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-param read-only tool with no output schema, this covers purpose, detection methods, error semantics, and cost. The only gap is that the returned structure (e.g., how the detected kind and addresses are presented) is not hinted at beyond 'names the kind found.'

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?

Single parameter at 100% schema coverage sets baseline 3, but the description adds a concrete example address showing the expected 0x hex form, which is slightly more than the schema's '0x contract address'.

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?

Specific verb+resource: 'Find the implementation behind a proxy contract on Base', and it enumerates the exact slots/standards checked (EIP-1967, beacon, admin, EIP-1822/UUPS, legacy OZ, EIP-1167). This is trivially distinguishable from sibling base_is_contract or base_storage.

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?

Explicitly states when to use ('before trusting or decoding a contract whose code can be swapped by its admin') and names the alternative ('for a fuller risk verdict use contract_risk'). The when-not and routing to a sibling are both present.

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