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

Annotations already declare readOnlyHint, idempotentHint, and destructiveHint, so the safety profile is covered. The description adds useful behavioral context beyond annotations: no key is required, it is not investment advice, and it uses specific screening logic including FINRA short-ratio deviation from the 20-day average. It does not describe output shape or refresh timing, but for a read-only screener this is adequate.

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 dense but well organized: screening inputs and examples come first, then usage timing, then access and disclaimer. The English parenthetical partially repeats the Korean content, but it is short and the overall structure is front-loaded and efficient.

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 one optional parameter and no output schema, the description covers the core needed information: what it returns, the screening logic, when to call it, auth requirements, and the disclaimer. The main gaps are the undocumented `limit` behavior and the lack of explicit return format details, but these are minor for a filter-style read-only 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 0% and the description never mentions the `limit` parameter. The agent must infer from the parameter name alone that it controls the number of returned stocks. The description does not compensate for the missing schema documentation.

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 uses a specific verb ('준다' = gives) and a specific resource: Korean stocks to watch, filtered by explicit conditions such as US leading indicators (VIX, Nasdaq 100 futures, SOX, Hynix ADR, Treasuries), paired US peers, or FINRA short-sale ratio spikes. It clearly differentiates the tool from sibling market-data tools by focusing on overnight US moves screening Korean equities.

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 explicitly states when to use the tool: '한국 장 시작 전에 부르면 좋다' (call before the Korean market opens). It also states the access requirement: '키 없이 쓸 수 있다' (no key needed). It does not explicitly name alternatives or when-not-to-use cases, so it stops short of a 5.

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