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

With no annotations, the description carries the full burden. It discloses the low-frequency data cadence, retention of historical daily data, and the PRO plan requirement (lower tiers return 403). This adds significant behavioral context beyond the schema. It does not cover error handling beyond 403, but the disclosed traits are substantial.

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 description is compact and well-structured with 'Args' and 'Returns' sections. Every sentence is essential, covering cadence, access requirements, and return fields. No fluff or redundancy. The front-loaded title phrase immediately conveys the resource.

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?

Given the tool's complexity, the description covers data frequency, auth constraints, parameters, and return fields. It does not explicitly state default behavior when no dates are passed, but the query suggestion implies that is acceptable. The presence of an output schema further reduces the need to explain return values. Overall, fairly complete.

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 baseline is 3. The description repeats parameter names and adds no new meaning beyond the schema. The note that trade_date is exclusive with start/end is already present in the schema description. No extra semantics provided.

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 opens with '北向持股明细（资金流向）' which clearly identifies the resource as northbound holdings details, distinguishing it from the sibling 'southbound_holdings'. Though it lacks an explicit verb like 'get' or 'query', the 'Returns' section confirms it provides data. The purpose is unambiguous.

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 description provides clear context on when to use this tool, explaining the disclosure rhythm change (no longer daily since Aug 2024) and giving a query suggestion: '查询建议不带日期或用较宽日期范围'. It does not explicitly name alternatives, but the context makes the use case clear. Lacks explicit 'when not to use' exclusions.

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