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

Annotations already declare this is a read-only, idempotent, non-destructive call, so safety is covered. The description adds genuinely non-obvious behavior beyond that: the exact qualification threshold, the field set returned, and the tier gating where Pro gets only a teaser and `locked` counts the remainder until Premium.

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 definition, then the returned fields, then the tier caveat — a sensible order. Three dense sentences with little waste, though the trailing 'Free.' is telegraphic and slightly unclear about what exactly is free.

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 usefully enumerates return fields (views, likes, outlier multiple, caption, URL, account, labels) and warns that labels may be null. Pagination is carried by the schema's cursor param, so the remaining gap is 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%, so uid, brand, limit, cursor and bearer_token are all documented in the schema itself, including the list_ugc_brands reference for brand. The description adds no parameter-level syntax or constraints beyond that, so the baseline 3 applies.

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?

Names a specific verb and resource (list winning organic TikTok/Instagram videos) and pins down the qualifying criterion precisely: at least 5x the account's median views, tier viral or winner. The 'organic, not paid' framing implicitly separates it from list_winning_ads, so an agent can pick correctly without opening the 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?

Gives a clear use case ('find proven organic formats and hooks') plus the conceptual definition that governs inclusion. It never names an alternative tool or says when not to use this one — e.g. versus search_ugc_database or list_tracked_videos — so the routing guidance stays implicit.

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