Reels

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

Beyond the annotations, it discloses that the call consumes paid credits and requires confirm=true, clarifies why a read-like POST does not publish to social platforms, notes that captions are not returned, and explains that play counts exclude Facebook cross-posts. This is rich behavioral context the structured fields don't carry.

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 dense and slightly long, but it is front-loaded with the resource definition and then layers the high-value caveats (timestamps, missing captions, credit cost). Nearly every sentence carries operationally useful information, with only minor compression possible.

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 carries the burden of explaining returns, and it does so thoroughly (fields, timestamp semantics, missing captions, view-count caveats). Combined with the annotations and a fully documented schema, an agent has what it needs to call this 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 100%, so the baseline is 3, but the description adds real meaning: trim shifts the timestamp field to items[].created_at, max_id drives cursor pagination, user_id yields faster responses, and confirm gates the credit-consuming call. The remaining fields (account) get no prose, but the added value is genuine.

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 ("Returns a paginated list of a user's public Instagram reels") and scopes it to short-form videos. It also enumerates the returned fields, so an agent can distinguish this per-user listing from search-based siblings like instagram_search_reels without opening a schema.

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 operating conditions: cursor pagination via max_id, a preference for user_id over handle for speed, and the confirm=true credit prerequisite. It does not explicitly route the agent to or away from sibling reels endpoints, so usage is clear but lacks explicit alternatives.

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