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

Annotations cover readOnlyHint and openWorldHint, so the safety profile is already handled. The description adds genuinely new behavioral context: the exact fields returned and a per-call cost ('[호출당 10포인트]'), which functions like a rate/cost disclosure the schema and annotations do not carry.

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?

Front-loaded with the resource and return fields, and the cost note is placed at the end. The English/Korean duplication doubles the token count, but it appears intentional rather than 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?

There is no output schema, so listing the returned fields in the description is the right compensation, and the cost note rounds it out. It omits failure behavior (private/deleted posts, invalid URLs), which is the main 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?

Only one parameter with 100% schema description coverage, including format examples (/p/코드/ or /reel/코드/). The description restates that the URL points to a post or reel but adds no syntax or format detail beyond the schema — baseline 3.

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-implied resource ('Instagram post or reel by URL') and enumerates exactly what is retrieved (likes, comments count, views, caption, hashtags, media URLs). This clearly separates it from the sibling instagram_profile, which is profile-scoped rather than post-scoped.

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 'by URL' framing implies the precondition (you already have a post/reel URL), but no when-to-use/when-not statement or alternative routing (e.g., instagram_profile for accounts) is given. Usage is inferable but not explicit.

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