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

Annotations already cover read-only/idempotent/open-world safety, yet the description adds real behavioral context: a daily per-caller free quota, which is a rate limit, and the instruction that payment credentials belong in X-Payment / X-Payment-Tx / Authorization headers rather than parameters. It also describes the payload returned. It stops short of stating what happens when the quota is exhausted or what the default 'large' threshold is.

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?

The purpose sentence is well front-loaded, but the text is duplicated across bilingual blocks that restate the same quota, argument list, and header advice twice, adding length without new information. The return-format detail is buried in the Chinese section rather than stated once up front.

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?

Return values are described, so the absence of an output schema is acceptable, and the auth/quota behavior is covered. The gap is on the input side: with four undocumented parameters and no output schema, an agent still cannot know valid chain values or the semantics of blocks and min_usd from this definition alone.

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 0% for all four parameters, so the description carries the full burden and does not meet it. It merely repeats the names (token, chain, blocks, min_usd) and says they are optional, without explaining the block window unit, accepted chain values, or what units min_usd uses.

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 opening phrase "who just moved a large amount of this token" plus the explicit return contents (transfer count and the single largest transfer with tx hash) state a specific verb and resource, so an agent can tell it apart from generic flow tools. It does not, however, name or differentiate itself from siblings like whale_report or whale_top5_entry.

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 definition establishes context (a free, quota-limited scan over recent N blocks) but never says when to choose it over whale_report or whale_top5_entry, nor when the free tier is insufficient. Usage is implied by the question it answers rather than stated.

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