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

With no annotations, the description carries the full burden and delivers key traits: it is a read-only query (只读查询), requires the paid 专业版（¥99）tier, and all figures are denominated in 元. It does not say whether the flow data is realtime or delayed, and gives no rate or coverage limits, which is the remaining gap.

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 and metrics, then use case, then sibling disambiguation, then unit and access warnings. Every sentence carries distinct information with no filler, despite the bold markup.

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-value explanation is unnecessary; the single required parameter is fully documented. For a one-param read-only query, the description covers purpose, alternatives, units, and access tier — everything needed to call it correctly.

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% and the single `code` parameter already documents the sh600519 / hk00700 format inline. The description's mention of 港股 support implicitly reinforces the code format but adds no new syntax or constraint beyond the schema, so the 3 baseline 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?

The description names a specific resource and verb (个股资金流向, 主力与散户的买入/卖出/净额 + 均价、收盘价) and scopes it to A-shares and Hong Kong stocks. It explicitly names the sibling `ashare_fund` and states the distinction, so an agent can separate the two 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 an explicit use trigger ('用户问"主力在进还是出/资金流多少"时用') and an explicit exclusion, noting that `ashare_fund` covers 龙虎榜+大宗+两融 for A-shares only, and that Hong Kong stocks must use this tool. When and when-not are both covered.

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