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

Annotations already declare read-only, non-destructive, open-world and non-idempotent behavior, so the bar is lower. The description adds genuinely new context: public accounts only, structured metadata rather than media files, and the accepted payment chains (Base/Polygon, not Solana). It does not mention rate limits or failure modes, keeping it below a 5.

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?

Five short sentences, front-loaded with what is read before what is returned. The payment-chain sentence is unusual but purposeful for a paid endpoint; the 'returns structured metadata' sentence slightly overlaps the earlier JSON field list.

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 only two parameters, no output schema, and complete annotation coverage, the definition is nearly self-sufficient: it enumerates returned fields and clarifies that no media is delivered. Missing only error/empty-result behavior and rate-limit expectations.

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 both parameters are already fully documented in the schema, including the limit clamping rules. The description reinforces the dual accept-mode of target (username vs direct reel URL) but adds no syntax, format, or precedence guidance beyond that.

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 (read reels) plus scope (one public account, or a single reel URL), and names the returned fields. An agent can distinguish it from siblings like instagram-comments or instagram-profile without opening any 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?

Offers one concrete use case ('compare short-video performance') and implicitly limits scope to public accounts, but never states when to prefer instagram-profile, instagram, or instagram-comments instead, nor any exclusions or prerequisites.

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