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

Annotations already declare readOnlyHint, idempotentHint, non-destructive and closed-world, so the safety profile is covered. The description adds one genuine behavioral fact beyond them — that an API key is required — but says nothing about pagination behavior (before_id), default page size, or result shape, which are the traits an agent would otherwise get wrong.

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?

Two compact sentences with the access requirement front-loaded before the purpose and ordering hint — nothing extraneous. The bilingual parenthetical "(List threads.)" is mildly redundant given the Korean already conveys the same, but it costs little.

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 five-parameter, all-optional read tool with full schema coverage and complete annotations, the description plus structured fields are nearly sufficient. The remaining gap is pagination and default-limit behavior, which an agent must reconstruct from the schema rather than the prose.

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%, with enums and descriptions for sort, board, limit, before_id and stock_code, so the schema carries parameter meaning. The description only restates board/stock filtering and the hot ordering already documented in the enum text, adding no syntax or edge-case detail (e.g., how before_id composes with sort).

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 gives a clear verb+resource in both languages ("게시판·종목별 게시글 목록" / "List threads") and states the scope is board- and stock-filtered posts. It does not name a sibling such as read_thread or create_thread to draw the boundary, so an agent must infer that this returns a list rather than a single thread from the noun "목록" alone.

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?

It provides one actionable prerequisite, "[키 필요]" (key required), and notes that sort=hot switches ordering to trending, which hints at when the parameter matters. There is no guidance on when to prefer this over read_feed or search, and no exclusion or paging guidance is offered.

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