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

Goes well beyond the annotations: discloses data windows (15 min Ethereum vs 3 min Base), that addresses are unlabelled, output fields (sender, receiver, tx, block, mints/burns), and a detailed pricing model ($0.01/call, first 25 free, failed calls free, repeats not free). These are operational traits an agent cannot get from readOnlyHint/openWorldHint alone.

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?

Purpose and scope are front-loaded, then filters, then usage and pricing. Information density is high, but the closing pricing/reads-only sentences are somewhat verbose and partly restate the annotations' safety profile.

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?

For a 4-param, no-output-schema tool, the description supplies ordering, defaults, coverage windows, labelling caveat, and pricing, which is enough to call it correctly. Return structure is only partially described, but nothing critical 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 schema already documents all four parameters with defaults and ranges. The description adds only the default min (100,000), the five chain names, and the 'largest first' ordering, which is marginal beyond the schema. Baseline 3 is appropriate.

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 (read large stablecoin transfers), the exact resources (USDC/USDT on Ethereum, Base, Arbitrum, Optimism, Polygon), and the filter (>= min USD, largest first). It distinguishes itself from the per-chain *_token_transfers siblings by being a cross-chain whale thresholded feed, though it never names those siblings 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?

"Use to watch whale flows, treasury moves or stablecoin mints" plus a concrete example (chain=ethereum) gives clear usage context. It does not, however, state when NOT to use it or point to the per-chain token_transfers alternatives for lower-threshold/general queries.

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