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

Annotations already declare readOnlyHint=true and openWorldHint=true, so the safety profile is covered. The description adds that results are 'normalized' and that pagination is page-based, which is genuine behavioral context, but it omits result counts, per-page limits, or region behavior.

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?

It is a single front-loaded sentence with no filler, but the enumerated field list duplicates what the existing output schema already provides, so that clause does not fully earn 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?

An output schema exists, so return values need not be re-explained, yet the description spends its text doing exactly that while leaving the required q parameter and the region parameter unexplained and offering no usage context. For a search tool with 0% schema coverage, this is inadequate.

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 0% for all three parameters (q, page, region). The description only hints at 'page-based pagination' for the page parameter and says nothing about q or region semantics, so it fails to compensate for the coverage gap.

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 identifies the resource (DuckDuckGo video results) and enumerates returned fields, but never states the action verb (search/fetch videos for a query). It reads like output-schema documentation rather than a statement of what the tool does, and it does not distinguish itself from siblings like duckduckgo_search or duckduckgo_image.

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?

There is no when-to-use guidance and no mention of alternatives such as duckduckgo_search (web) or duckduckgo_image. The only operational hint is 'page-based pagination', which describes iteration but not tool selection.

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