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

With no annotations, the description carries the full burden. It does disclose the 403 error for insufficient subscription tiers and the exact return format (JSON array with fields). However, it does not mention read-only status explicitly (though implied), rate limits, or error handling for invalid inputs.

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 distinct sections for requirement, arguments, and returns. It is relatively concise, though the Args section duplicates the schema descriptions, which is mildly redundant. The main purpose is front-loaded.

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 details are not required. The description does not explain how the date parameters and period interact (e.g., whether period is an alternative to start/end_date). All parameters are optional, and no guidance on valid combinations is provided, leaving some ambiguity for agents.

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?

The input schema has full descriptions for all four parameters (100% coverage). The description's Args section repeats these descriptions verbatim, adding no new semantics such as valid combinations or parameter relationships. Baseline 3 is appropriate since 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?

The description opens with '主营业务构成（财务数据）', which clearly identifies the resource as main business composition. Although it lacks an explicit verb like 'Get' or 'Retrieve', the Args and Returns sections make its data-retrieval purpose obvious, and it is distinct from sibling financial tools.

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 mentions the premium requirement ('需要 PRO 及以上套餐（低档位调用返回 403）'), which is a prerequisite, but it does not provide guidance on when to use this tool versus alternatives like income or balance_sheet. No exclusions or preferred scenarios are given.

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