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

Annotations already declare readOnlyHint, idempotentHint, openWorldHint and destructiveHint=false, so safety is covered structurally. The description adds real value beyond them by disclosing billing behavior: ¥0.3 per call, only successful calls billed, failures and empty results auto-refunded. It doesn't describe pagination, rate limits, or what an empty/private post looks like, so it stops short of rich behavioral disclosure.

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?

Purpose is front-loaded in the first clause, then returns, then usage, then pricing. Each sentence carries information an agent needs, with no filler. Slightly list-like enumeration of return fields keeps it from being maximally tight.

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 correctly compensates by enumerating what comes back (copy, engagement counts, author, media list, publish time). Pricing, refund policy and use cases are all covered for a simple 2-param read tool. Minor gaps: shortcode format expectations and behavior on private/deleted posts.

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%, so both parameters ('code' and the _token fallback) are already documented in the schema. The description only echoes that lookup is by shortcode and adds no format detail, such as an example shortcode string, so it lands at the baseline for high-coverage schemas.

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 names a specific verb and resource ('按shortcode获取Instagram帖子详情'), plus an identifier type, so an agent can tell it apart from ig_post_comments or ig_user_posts. It enumerates returned fields (文案、点赞/评论数、作者信息、媒体列表、发布时间), making scope concrete. It never explicitly names a sibling it is not, which keeps it just short of a 5.

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 gives concrete when-to-use scenarios: single-post engagement analysis, material archiving, or as the entry point for batch jobs ('作为批量任务起点'). What is missing is exclusion guidance: it doesn't say to use ig_post_comments for comment threads or ig_user_posts to enumerate a user's posts, and it doesn't state the shortcode prerequisite.

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