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

Goes well beyond the annotations: documents specific failure semantics (malformed address = 400, no code = 404, both uncharged), pricing ($0.01/call, first 25 free, failed calls free), and the side-effect profile ('reads or computes only and changes nothing'). The 'each call is charged, so repeats are not free' note is consistent with idempotentHint=false rather than contradicting it.

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-loads the capability and pattern list before the usage guidance, and every clause (error codes, pricing, read-only nature) is actionable. The pricing/credits tail is slightly dense but genuinely relevant to an agent deciding whether to call.

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 no output schema, the description still conveys the return shape at a high level ('names the kind found') and which slots are inspected. Error codes and cost are covered, so an agent could invoke it confidently; only the exact response fields are unspecified.

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?

Only one parameter with 100% schema coverage ('0x contract address'), so the schema already carries the semantics and baseline 3 applies. The description adds a concrete example address and implies the address must be a deployed contract (404 if no code), but no format details beyond the schema.

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 verb and resource ('Find the implementation behind a proxy contract on Scroll') and enumerates exactly which slot standards it reads (EIP-1967, beacon/admin, EIP-1822/UUPS, OZ legacy, EIP-1167) plus what it returns ('names the kind found'). The chain prefix in the name plus the explicit 'on Scroll' cleanly separates it from the ~20 sibling *_proxy 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?

Gives a clear trigger ('Use before trusting or decoding a contract whose code can be swapped by its admin') and names an alternative ('for a fuller risk verdict use contract_risk'). It does not explicitly contrast with nearby tools like scroll_is_contract or scroll_storage, but the when-to-use condition is explicit.

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