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

With no annotations, the description carries the behavioral burden well: it warns that ranking/hotness fields are not measured search volume, notes region/session variance, and states there is no pagination. It still omits any auth or rate-limit context, 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?

Four short sentences, all load-bearing: purpose, return shape, sibling disambiguation, caveats. Front-loaded with the core action; slightly dense but nothing is wasted.

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, so the description steps in by naming the returned fields (trending_search_words plus source metadata) and flagging interpretation pitfalls. Enough to call it correctly, though return structure detail is only partial.

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% and the single parameter is already documented, so the baseline is 3. The description adds real meaning by framing the call as 'one native batch' with no pagination parameter, clarifying that count is a soft page-size request rather than a traversable cursor.

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 ('Get one native batch of TikTok web trending search phrases') and explicitly distinguishes itself from the sibling trending_topics with its queryId records. An agent can tell it apart 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?

Names the alternative ('separate from CSI trending_topics') and characterizes its own scope as web search discovery, giving clear context for selection. It stops short of an explicit 'use this when / not when' rule, but the routing intent is unambiguous.

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