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

Annotations already declare readOnlyHint=true and openWorldHint=true, so safety and external-data dependence are covered. The description adds real behavioral context beyond them: on-chain ERC-20-only scope, the etherscan data source, and the per-call price. It stops short of stating rate limits or how far back 'recent' extends.

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 purpose first, then Use when / Not for / Returns / example, so an agent can stop reading early. The example response is long and padded with dummy hex addresses, but it is justified because no output schema exists.

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 carries the return contract itself, listing large_transfers fields, total_volume_usd, and a concrete example. The main gap is that 'recent' is never quantified (time window), and error/rate-limit behavior is unstated.

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%, so both parameters (token, min_usd) are already documented with the default. The description adds no syntax, symbol-format, or threshold guidance, so the baseline 3 applies.

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 gives a specific verb+resource ('Detect recent large wallet movements for a token') and immediately glosses it as 'whale tracking'. It is unambiguous and distinguishable from siblings like wallet_balance and orderbook_depth, which are named explicitly.

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?

Explicit 'Use when' (institutional moves, accumulation, sell-offs) and 'Not for' clauses that route the agent to wallet_balance for single-address holdings and orderbook_depth for exchange book size. The 'Ethereum ERC-20 transfers only' constraint closes the remaining ambiguity.

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