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

The annotations already declare readOnlyHint, idempotentHint, destructiveHint=false and openWorldHint=false, so safety behavior is covered. The description contributes provenance and freshness ("최근 정기보고서", "모두 DART 공시 기반", original-text quotes with DART links), which is genuinely useful, but it says nothing about behavior when a ticker is unknown, when a company has no recent report, or about response size/latency.

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 routing cue is front-loaded in the first clause, followed by a compact enumeration of outputs and a source note. It is one dense sentence with no filler, though the parenthetical asides make it slightly heavy on first read.

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?

There is no output schema, so the description must carry the return-value burden — and it does, naming each returned block (segments, quarterly trend, cited earnings-change reasons with links, overview, dividends, record date). What is missing is data-freshness granularity (which quarter's report) and empty/error behavior, but for a single-parameter read tool this is nearly complete.

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 single `stock` parameter is fully documented in the schema with format and examples ('005930', '삼성전자'). The description adds no additional meaning about ticker resolution (e.g., market prefix, name ambiguity), so the baseline 3 applies.

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?

"종목 한눈에 — 특정 종목 질문은 여기서 시작" states the resource (a single stock) and that this is the entry point, and then enumerates the concrete payload (segment breakdown, quarterly trend, stated reasons for earnings changes, business overview, dividends/buybacks, upcoming record date). It is unambiguously about one company, but it never contrasts itself with the many overlapping siblings (financials, earnings, business_trend, shareholders), which is the only thing keeping it from a 5.

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?

"특정 종목 질문은 여기서 시작" is a real when-to-use cue for single-stock questions, and the DART-source note bounds the domain. However, there is no when-NOT-to-use and no routing to alternatives such as earnings for detailed quarterly figures or price for quotes, so the agent must infer boundaries by inspecting sibling names itself.

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