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

Annotations only cover readOnlyHint and openWorldHint, yet the description adds what an agent actually needs: site-specific cost ($0.002 USDC per successful call), payment rail (x402 on Base, Solana or Arc), and the crucial billing rule that failed calls are free. It also discloses the data source and the 50-transaction lookback window that bounds the result's reliability.

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?

Three tight clauses — what it checks, how reliable that is, what it costs — with the scope and method front-loaded and no filler. Every sentence carries decision-relevant information.

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-shape explanation is unnecessary, and the description still names the headline signal. Combined with the coverage of pricing, data source, lookback depth and known blind spots, an agent has everything needed to invoke it and to interpret a null result.

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 there is a single parameter whose schema text already specifies '2 to 10 Ethereum addresses separated by commas'. The description restates the 2-to-10 range and pins the chain to Ethereum, but adds no format or edge-case guidance (e.g. duplicates, invalid addresses) beyond the schema, so 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?

States a specific verb (checks), a specific resource (2-10 Ethereum wallets), the exact method (shared counterparties among the last 50 transactions via Blockscout), and the output signal (POSSIBLE_CLUSTER). That level of mechanism detail lets an agent separate it from neighbor tools like holder_cluster_analyzer or wallet_forensic_profiler without opening the schema.

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 description supplies clear context for choosing this tool — it is a multi-wallet cluster test, not a single-wallet profiler — and the caveat 'recent-page only, no funding-source trace, so it finds some clusters and misses others' tells the agent when a negative result is weak evidence. It stops short of naming an explicit alternative for funding-source tracing, so no full when/when-not routing.

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