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

Annotations already declare readOnlyHint=false, idempotentHint=true, destructiveHint=false, so the safety profile is covered. The description adds valuable behavioral context: it mentions the 'degraded quality flag' for small regions, the client-side cutoff for window, and the platform-specific note that Instagram ignores region/date_posted params. This goes beyond annotations and helps the agent understand edge cases.

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?

The description is concise, with the core purpose front-loaded and filters summarized in one sentence. It's efficient and doesn't waste words. A slight deduction because it could be slightly more structured (e.g., bullet points for filters), but it's still well-organized and readable.

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 the tool's complexity (7 params, 2 enums, platform-specific behavior), the description covers the key points: what it returns, when to use it, and the main edge cases (region coverage, platform differences). The output schema exists, so return values are covered. It doesn't mention pagination or rate limits, but those are minor for a search tool. A 4 is fair.

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 the schema already documents all parameters well. The description adds value by summarizing the optional filters (niche, minimum views, recency window, region) and by noting the 'degraded quality flag' for regions, which is not in the schema. It doesn't repeat schema details but adds a layer of context, so a 4 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?

The description states a specific verb ('Search'), a resource ('short-form videos'), and the platforms ('TikTok or Instagram'). It clearly distinguishes from siblings like 'find_viral_template' or 'trend_pulse' by focusing on keyword search for videos. The scope and output are explicit.

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?

The description explicitly says 'Use when the user asks to find videos about a topic or keyword,' which provides clear context. It doesn't explicitly name alternatives or when-not-to-use, but the sibling list and the specific phrasing make the usage context clear enough. A small deduction for not naming alternatives explicitly.

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