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

Annotations already declare readOnly, idempotent and non-destructive, so the description's added value is elsewhere: it discloses the result cap (top 20), the returned metrics (views, viral multiple, trend grade) and the cost (1 credit), which is meaningful given the estimate_cost sibling.

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?

Three short sentences: what it searches, what comes back, what it costs. Front-loaded with the purpose and no filler; the credit note is the only 'extra' and it earns its place.

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?

There is no output schema, and the description does compensate by naming the returned fields and the 20-item cap. But for a 4-parameter tool with 25% schema coverage and two enums, the missing sort/platform semantics leave the definition incomplete for correct invocation.

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 only 25% — just country is documented — so the description must carry the weight and it does not. It never explains the six sort modes (trend, velocity, rising, performance…) or what the platform enum values map to, which are exactly the parameters an agent will guess wrong on.

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 (search short-form content) plus the concrete platforms covered (Shorts, TikTok, Reels) and the discovery axis (topic). It does not distinguish itself from overlapping siblings such as trending_items, similar_content or keyword_trend, so an agent cannot resolve the boundary from the description alone.

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?

Usage is only implied by 'by topic' — the reader infers this is a topical search rather than a browse, but there is no statement of when to prefer it over trending_items or similar_content, and no exclusions or prerequisites.

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