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

Annotations only assert readOnly and openWorld. The description adds real behavior beyond that: results are in Instagram's own order, only one page is returned, hasMore signals whether more exists, and each call costs 1 credit. That is meaningful operational context an agent needs.

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 core purpose and kept to two sentences. The opening phrase 'Top posts for a keyword' is immediately restated ('Top posts for a keyword from...'), a minor redundancy, but nothing else is wasted.

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 carries the return-shape burden and does so partly: it names content types, states ordering, and explains hasMore. It omits the return format beyond hasMore and says nothing about cache_max_age, but overall it is sufficient to call the tool correctly.

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 67%; query and cursor are documented in the schema, while cache_max_age is undocumented in both. The description implies cursor-based paging via 'one page' and 'hasMore' but adds no query formatting or cache semantics. Baseline 3 fits.

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 and resource ('Top posts for a keyword') and pins it to a named surface, Instagram's Popular page at instagram.com/popular/<keyword>/. It also enumerates content types (reels, images, carousels), which distinguishes it from siblings like instagram_search and instagram_hashtagPosts.

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 implies usage through 'Popular page' and 'one page', but never explicitly says when to pick this over instagram_search, instagram_hashtagPosts, or instagram_reelsSearch. An agent must infer the distinction from the page URL alone.

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