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

No annotations exist, so the description carries the full burden. It discloses that this is a read (조회) that returns both the fact record and the primary-source excerpt, which is genuine behavioral content. It says nothing about auth requirements, rate limits, or not-found behavior for an invalid ID/slug.

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?

A single front-loaded sentence with no filler; the resource and lookup key come first. The ID examples are the only slightly distracting insertion, but they are useful, not wasteful.

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 one-parameter lookup with no output schema and no annotations, the description is largely sufficient: it identifies the input formats and states that the returned content includes the fact record and source excerpt. More detail on ID-not-found handling or the shape of the returned record would close the remaining gap.

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 0% — the id parameter is only typed as a 2-100 char string. The description compensates well by specifying the accepted formats: permanent fact IDs with concrete examples (F-01, F-39) or a slug, which the schema alone does not convey. It stops short of stating whether ID and slug are mutually exclusive.

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 specific verb (조회) and resource (단일 팩트 레코드), plus the retrieval key (영구 팩트 ID or 슬러그) and the additional payload (1차 출처 원문 발췌). This clearly separates it from the search_* siblings, though no sibling is named explicitly.

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 single-record-by-ID framing implies lookup rather than search, and the ID examples (F-01, F-39) help the agent supply the right input. However, it never states when to prefer this over search_facts or search_verified_facts, nor any prerequisite for having an ID/slug already in hand.

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