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

With no annotations provided, the description does some of the disclosure work: it states the operation is limited to public posts, costs 1 credit, and requires an Authorization: Bearer header. However, it omits error behavior for invalid shortcodes, rate limits, and any mention of pagination or caching.

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 purpose and returned fields are front-loaded, and the credit and auth boilerplate is short. It is slightly marred by the stray double period after 'sample..' and dense appended 'Platform=instagram resource=post' metadata, but nothing is meaningfully 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?

There is no output schema, so the description must convey return values, and it does so by listing the main fields returned. Cost and authentication requirements are also covered. Remaining gaps (failure modes, pagination for larger comment samples) are minor for this tool's complexity.

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, n_comments_to_fetch) are already documented in the schema. The description's reference to a 'shortcode' and a 'small comments sample' only loosely restates that, adding no format or bounds detail beyond the schema's 0-50 range.

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 (fetch) and resource (public post details by shortcode) and enumerates the returned fields (caption, owner, likes, comments count, media URLs). It implicitly distinguishes itself from the plural sibling instagram_posts by operating on a single shortcode, but it never names or contrasts siblings like instagram_detailed, which could also plausibly return post details.

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 only implies usage via the required shortcode; it never states when to call this tool versus instagram_posts, instagram_detailed, or instagram_comments. There are no exclusions, prerequisites, or alternative-naming guidance.

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