get_douyin_download_link

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

With no annotations, the description carries the full burden. It does disclose the return format (JSON string with download link and video info) and the watermark-free promise, but it omits any caveats about invalid links, request failures, or underlying network behavior. That is a moderate but not complete level of transparency.

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 tightly written: a one-line purpose, a one-line parameter explanation, and a one-line return summary. No filler or repetition is present, and the key information is front-loaded.

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?

The tool is simple and an output schema exists, so the return contract is already defined. However, the description does not explain how this download-link tool relates to siblings or what preconditions apply to the share_link, leaving some context gaps for an agent choosing among similar tools.

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?

The schema only provides the parameter name and type, while the description adds important meaning: the share_link can be a share link or any text containing the link. This materially helps the agent construct a valid invocation and justifies a score above the 0%-coverage baseline.

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 ('获取'/fetch) and a clear resource ('抖音视频的无水印下载链接'/watermark-free Douyin video download link), which differentiates it from siblings that extract text, recognize audio, or parse video info.

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?

No guidance is given about when to prefer this tool over the listed siblings such as parse_douyin_video_info or extract_douyin_text. The description only says what the tool does and the required parameter, leaving the selection decision entirely to inference.

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