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

Annotations already cover the read-only and open-world safety profile, and the description adds real behavioral context beyond that: fixed page size of 12, returned fields, pinned-first then newest ordering, private-account edge case (empty list + is_private: true), cursor pagination, and a stated cost of 1 credit. Only error/failure behavior is left unspecified.

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?

Extremely dense and front-loaded: purpose first, then pagination/page contents, ordering, edge case, paging mechanism, and cost. Every sentence earns its place with no filler.

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 must describe returns and largely does: fields per post, ordering semantics, and the private-account response shape. It is complete enough to call and interpret results, though it does not cover rate-limit or error outcomes.

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 100% with self-documenting cursor/user_id/username fields and an example for username, so the schema carries the load. The description only adds that cursor drives pagination, which is baseline-level value over the 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?

States a specific verb ('Get') and resource ('recent Instagram posts'), and the '12 per page' and ordering details make it recognizable as the profile-feed listing tool. However it never explicitly contrasts itself with close siblings like instagram_post, instagram_media, or instagram_tagged, so the agent must infer the boundary.

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?

Usage is implied rather than stated: 'Page with cursor' signals a paginated fetch, and the private-account note implies a pre-check. There is no explicit when-to-use or when-to-prefer-a-sibling guidance (e.g. instagram_post for a single post, instagram_reels for video-only).

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