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

Annotations already declare readOnlyHint=true and openWorldHint=true, so safety is covered. The description supplies real added context: the label source (brianleect/etherscan-labels on GitHub), that labels are community-made and may be stale, the 10-wallet cap, and x402 pricing of $0.002 USDC per successful call with failures not charged. That is meaningful disclosure beyond annotations, though it says nothing about latency or freshness of the balance snapshot itself.

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?

Two sentences, front-loaded with the resource and its scope limits before the commercial terms. Dense and nearly waste-free, though the GitHub owner/repo path is more detail than an agent needs to select or call the 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?

An output schema exists, so return-format explanation is unnecessary; the description still covers data source, sampling limits, label reliability, and cost model. Nothing an agent needs in order to decide whether and how to call it is missing.

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 coverage is 100%, so the sole `exchange` parameter is already documented; the baseline would be 3. The description earns above baseline by naming the three accepted values and tying them to the labeling source, confirming what "exchange" filters on and warning that matching is label-dependent rather than exhaustive.

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 concretely what is returned: a native-ETH balance snapshot for up to 10 wallets labeled Binance/Coinbase/OKX. It also carves out scope against lookalikes (no token balances, no inflow/outflow history, not total reserves), which distinguishes it from siblings like agent_intel_whale_transaction_monitor and agent_intel_smart_money_inflow_tracker, though those tools are not named.

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?

The negative scoping ("snapshot of a sample, not total exchange reserves: no token balances, no inflow or outflow history") implies when the tool fits, but there is no explicit "use when" statement or named alternative for full reserve or flow data. Usage must be inferred from the limitations.

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