Instagram MCP Server

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

No annotations are provided, so the description carries full burden. It mentions what the tool does but lacks behavioral details: no information about authentication requirements, rate limits, error conditions, pagination behavior, or what happens with invalid usernames. The description states it returns '投稿一覧の文字列' (posts list as string) but doesn't describe the format or structure of that string.

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 description is reasonably concise with clear sections (Args, Returns). However, the initial purpose statement is somewhat redundant with the tool name, and the structure could be more front-loaded with critical information. The Japanese formatting is clean but not optimally organized for quick scanning.

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?

Given 2 parameters with 0% schema coverage but good parameter explanation in the description, plus an output schema exists (though not shown), the description is moderately complete. It covers the basic purpose and parameters but lacks behavioral context that would be important for a social media API tool (authentication, limits, error handling). The existence of an output schema reduces the need to describe return values in detail.

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?

With 0% schema description coverage, the description compensates well by explaining both parameters: 'username: Instagramユーザー名（@なし）' clarifies the username format (without @ symbol), and 'count: 取得する投稿数（デフォルト: 12）' explains it's the number of posts to retrieve with a default value. This adds meaningful context beyond the bare schema.

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 clearly states the tool's purpose: 'Instagramユーザーの投稿一覧を取得します' (Get Instagram user posts list). It specifies the verb ('取得します' - get/retrieve) and resource ('投稿一覧' - posts list), though it doesn't explicitly differentiate from siblings like 'instagram_user_tagged_posts' or 'instagram_user_reels'. The purpose is clear but lacks sibling differentiation.

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 description provides no guidance on when to use this tool versus alternatives. With multiple sibling tools available (instagram_user_info, instagram_user_reels, instagram_user_tagged_posts), there's no indication of when this specific posts retrieval tool is appropriate versus other user-related tools. No usage context or exclusions are mentioned.

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