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

No annotations, so the description carries the full burden and does: current-day-only with fallback to the most recent trading day on holidays/pre-open, a hard cap of ~200 rows with instructions to raise `money` when `total` > `returned`, and an institutional-tier gate that returns an upgrade notice for other plans. These are exactly the operational behaviors an agent needs before calling.

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 the resource, then use cases, then sibling routing, then caveats — a good structure. Slightly dense: the full `direction` enumeration and row-field list partially duplicate the output schema, so not every token is strictly new information, but nothing is genuinely wasted.

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 3-parameter read tool with an output schema and no annotations, the description covers everything that matters: scope (today only), truncation handling, access tier, and interpretation caliber. Return-shape explanation can be left to the output schema, and it is.

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 `code`, `limit` and `money` are already documented including the 0=30万 … 4=1000万 ladder. The description's only added value is the workflow hint that raising `money` is the remedy when `total` exceeds `returned`, which is useful but modest; baseline 3 applies when the schema does the heavy lifting.

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?

Names a specific resource and granularity: L2 large-order trade prints for the current day, every fill tagged active/passive × buy/sell. It also explicitly contrasts itself with the nearest sibling (`ashare_bigorder` gives per-minute net curves, this gives tick-level detail with a four-way split), so an agent can pick between them without opening either 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?

Gives concrete user phrasings that should route here ('谁在主动买/有没有人在扫货/大单是主动还是被动成交') and names the alternative tool with the criterion that selects it. It also states what this is NOT (not tick-by-tick order queue, not level-10 order book), which prevents a common misselection.

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