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

Annotations already declare readOnlyHint, idempotentHint, destructiveHint=false, and openWorldHint, so the safety profile is covered. The description adds genuinely useful non-safety context: one row per trading day, sign semantics (positive = net buying pressure, negative = net selling), and the keyless Eastmoney source. It stops short of stating pagination/limits behavior for days>available data.

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 and output shape are front-loaded in the first sentence, with supporting detail (sign semantics, source) trailing. Despite its length, every segment carries information — the field breakdown, the interpretation rule, and the source — with no filler.

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?

There is no output schema, so the description must carry return-value meaning — and it does, enumerating the per-day columns (four order-size buckets plus 主力净流入, in CNY and % of turnover) and explaining the sign convention. Combined with 100% parameter coverage, an agent has everything needed to call and interpret this tool.

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% — both 'code' (6-digit format, prefix tolerance) and 'days' (1–200, default 20) are fully documented in the schema. The description adds no parameter syntax or format detail beyond what the schema already provides, so the baseline of 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+resource+scope: per-stock daily main-capital net inflow history for A-shares/ETFs, with the exact breakdown (超大单/大单/中单/小单 + 主力净流入). This clearly distinguishes it from siblings like ashares_daily_history, ashares_margin_financing, or ashares_quote, which cover price/financing/quote respectively, not order-size capital flow.

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?

Several concrete example queries ('主力净流入历史', '000768最近20个交易日的主力资金流向', 'which days did big money flow into/out of a stock') make the intended use case obvious. However, it never explicitly states when NOT to use it or names a sibling as the alternative for overlapping cases (e.g. plain price history), so usage is well-implied but not fully disambiguated.

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