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

With no annotations, the description carries the full burden, and it does disclose a genuine behavioral trait: results are gated by subscription tier, with undisclosed 'underwater' event identifiers visible only to high-privilege plans. It says nothing about pagination (cursor/page_size), result limits, ordering, or what happens when no filters are supplied, which are material for a 12-parameter query tool.

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?

A single dense sentence, front-loaded with the resource and the primary retrieval mode, then return contents, then the permission caveat. No filler, though the return-field enumeration is partly redundant given an output schema exists.

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?

For a tool with twelve undocumented parameters, no annotations, and no required fields, the description is too thin: an agent cannot tell how the id-array filters combine, whether filters are ANDed, or how to page. The existence of an output schema excuses it from describing return values, but the input-side gap remains substantial.

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 0%, so the description must compensate, yet it explains only event_ids (exact retrieval) and implicitly is_underwater. The remaining ten parameters — fa_ids, company_ids, round_ids, scope_ids, sub_scope_ids, date_start, date_end, fields, page_size, cursor — receive no meaning, format, or interaction guidance anywhere.

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 verb and resource ('查询结构化FA服务案例') and adds a concrete capability ('按 event_ids 精确取回已知事件的 FA'), so an agent can tell it is a FA-case search rather than a generic company/investor search. It does not, however, contrast itself with close siblings such as search_company_investment_cases or search_investor_cases, leaving the boundary to be inferred.

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?

One usage context is given explicitly: use event_ids to retrieve the FA for already-known events. There is no statement of when to prefer this over the sibling investment-case searches, no exclusions, and no note that all twelve parameters are optional and the call therefore needs at least one filter to be meaningful.

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