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

Annotations already declare readOnly/idempotent/non-destructive, and the description adds behavior well beyond them: wrong-region calls return 401, the account's registered region overrides the region argument and cannot be mixed, and the response embeds channels[] summaries. It also discloses pagination behavior (default 100, usually one call suffices, check pagination.total to continue).

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 critical anti-pattern warning is correctly front-loaded and the text is sectioned by concern, which helps. However, the region paragraph and the pagination paragraph substantially duplicate what the region and per_page schema descriptions already say, so several sentences do not add information beyond structured fields.

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?

With no output schema, the description compensates by describing the response shape (per-category fields plus channels[] and pagination.total/current_page). For a read-only, zero-required-parameter listing tool, an agent has everything needed to call it correctly and to iterate pages.

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 coverage is 100%, so the baseline is 3; the description nonetheless adds real meaning about region selection (decide from user context, confirm when ambiguous, account region wins, 401 on mismatch) and about parent_category_key returning all descendants versus the full tree when omitted. The page/per_page guidance largely restates the schema, so it is not fully additive.

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 specific verb and resource ("Kollus VOD 카테고리 트리를 조회한다 (GET /categories)") and enumerates the returned fields (key, name, parent_key, level, children_exist, position, channels[]). The hierarchy semantics (parent_key=null means top-level, level indicates depth) let an agent distinguish this tree-listing call from flat listing siblings such as vod_channel_list.

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 states an explicit prohibition (no polling/setInterval/refetchInterval for CMS or DB sync) and redirects to kollus://anti-patterns/cms-admin-site, then lists four recommended one-shot use cases. What is missing is any explicit routing against sibling tools (e.g., vod_channel_list for channel-focused needs), so the alternative-selection half of the guidance is left to inference.

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