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

With no annotations, the description carries the burden and does disclose two non-obvious traits: the data source (Alchemy's transfer index) and the cost ($0.01 USDC on Base via x402), which materially affects agent behavior. It does not cover caching, rate limits, or failure modes for unknown/inactive addresses, keeping it short of a 5.

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?

One dense, front-loaded sentence that leads with the core question and then lists returns, plus a separate cost/source sentence. The return-value enumeration is long but each item is informative; minor density cost from listing every asset type (ETH, WETH, USDC, USDT, NFTs).

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 and no annotations, the description must explain what comes back — and it enumerates return contents thoroughly, plus cost and data source. Missing only edge-case behavior (address with no history, invalid checksum, pagination/limits on 'latest transfers') to reach a 5.

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% and the single `address` param is documented with a pattern, so the schema does the heavy lifting. The description adds only the network scoping ("OP Mainnet address"), matching the baseline 3 for full schema coverage.

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?

Opens with a specific question-prefixed verb ("Who is this OP Mainnet address?") and enumerates the exact resource contents: wallet age, first funder, contract vs EOA, ETH balance, nonce, transfers, counterparties, large USD transfers. That enumeration clearly separates it from siblings like optimism_wallet_balances (balances only) and optimism_transaction_summary (single-tx detail).

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?

Usage is only implied via the question framing — an agent can infer "use this to profile/due-diligence an address," but there is no explicit when-to-use, when-not-to-use, or named alternative among the many optimism_* siblings. No exclusions or prerequisites (e.g., address must be on OP Mainnet) are stated beyond the schema.

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