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 return format (JSON array with specific fields), the error condition for insufficient plan level, and parameter constraints. This provides substantial transparency for a read-only data retrieval tool, though it could mention rate limits or pagination.

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 well-structured with required plan, args, and returns, but the Args block duplicates the schema's property descriptions, making it redundant. A more concise version could integrate parameter details more efficiently.

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?

The description covers the key context: the whole-market scope, the PRO requirement, the date parameter modes, and a clear return schema with field names. For a tool of this complexity, it is sufficient, though it does not explain the meaning of each returned field (e.g., ggt_ss vs hgt_ss) which might be helpful.

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%, and the Args section in the description largely repeats the schema's descriptions. The only added value is the explicit '与 start/end 二选一' mutual exclusion, which is already present in the schema. No meaningful new semantics beyond the structured data.

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?

Description clearly states '沪深港通资金流向（全市场）' (whole-market Stock Connect capital flow), providing a specific resource and action. It distinguishes itself from sibling tools like 'moneyflow' by emphasizing '全市场' (whole market).

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?

Mentions PRO+ requirement and the 403 error for lower tiers, which is useful context. Also notes the mutual exclusion of trade_date with start/end. However, it does not explicitly discuss when to use this tool versus sibling tools like moneyflow, northbound_holdings, or southbound_holdings, leaving comparison to the agent.

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