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

Annotations already declare readOnly/idempotent/non-destructive, so the safety profile is covered. The description adds genuinely non-obvious behavior: the data is prior-day closing data, '집계 전' means the trading day has not elapsed rather than 0%, and the reference date must be quoted verbatim rather than paraphrased as 'today'. These are real operational caveats beyond the annotations.

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?

Purpose is front-loaded in the first sentence, and each subsequent sentence carries a distinct fact (data freshness, aggregate-not-zero clarification, quoting rule, advisory exclusion). The phrasing is somewhat telegraphic, but nothing is padding.

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?

No output schema exists, so the description must carry return-value meaning, and it does address the first line's reference date and the '집계 전' value. It stops short of describing the list/performance fields themselves, but covers the return-interpretation risks an agent is most likely to mishandle.

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%, so parameters (code, from, to, limit, format) are already documented including the enum and default for format and limit. The description adds no parameter-level detail such as date-range semantics or code format, so the baseline 3 is appropriate.

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?

States a concrete verb+resource: it tells when a stock was added to which list and how it performed afterward, and explicitly labels itself '과거 통계 조회 도구' (historical statistics lookup). It does not, however, differentiate itself from close siblings like maedong_signals or maedong_signal_stats, leaving some ambiguity about which signal-related tool to pick.

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?

Provides a clear exclusion: 'do not use it to generate buy/sell decisions for a specific stock.' This frames the intended regime of use (descriptive history, not advisory). It does not name an alternative tool to use instead, so the routing guidance is incomplete but still meaningful.

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