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

Annotations already declare readOnlyHint=true and openWorldHint=false, so the safety profile is covered. The description adds that the tool computes viral velocity and engagement metrics, but it does not describe return shape, limits, or any behavioral caveats beyond that.

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?

Two focused sentences, front-loaded with the core purpose and followed by concrete usage triggers. No wasted words or redundant restatement.

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?

Given complete schema coverage and annotations, the description supplies enough context to call the tool correctly. It could do slightly more to clarify what kind of result set comes back, since there is no output schema, but the gaps are minor.

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% and the sort enum, default, and limit bounds are fully documented in the schema. The description adds no parameter-level guidance beyond echoing viral velocity as a metric, so baseline 3 is appropriate.

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: analyze Instagram Reels performance, with named metrics (viral velocity, engagement rates, view metrics). It is clearly Reels-specific, though it does not explicitly distinguish itself from related siblings like get_post_insights or get_top_posts.

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?

Gives clear usage triggers: Reels performance, video strategy, viral content, or which Reels perform best. It does not name exclusions or alternatives, so it falls short of a 5.

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