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

Annotations already cover read-only, idempotent, non-destructive and closed-world behavior, so the description's job is to add operational context — and it does: default scoping when no filters are supplied, result ordering, the fields returned, and the special behavior of list_filters. It stops short of describing pagination behavior (the offset/next_offset loop) or result-count limits.

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 trigger condition, then defaults, then the sibling routing — a sensible order with no filler. The first clause is long and comma-chained, which slightly hurts scanability, but every sentence carries information.

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?

No output schema exists, and the description compensates by listing the returned metrics (views, likes, comments, shares), so an agent knows what comes back. The gap is pagination: offset/next_offset is a real part of using this tool at scale and is never mentioned.

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 86%, so most parameters are already documented; the description nevertheless adds real meaning by explaining the default scoping for place and niches and by giving semantics to list_filters, which has no schema description at all. It does not clarify the difference between the 'views' and 'score' sort modes beyond the terse enum text.

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 — lists trending videos and ads across TikTok, Instagram, YouTube and Facebook — plus the dimensions (niche, place, language), the returned metrics, and the ordering (most viral first). It is clearly distinguishable from get_viral_idea, which is named as the single-result counterpart.

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?

Opens with an explicit trigger ('when the user wants ideas from what is going viral right now'), documents the no-filter default (user's own niches and region), and routes to the alternative ('For one result, call get_viral_idea'). Both the when and the alternative are stated rather than inferred.

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