youtube-video-downloader

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

No annotations are provided, so the description carries the full burden of behavioral disclosure. It only names the operation 'download' and gives no details about the return value, whether a file path or URL is produced, whether authentication or cookies are needed, or how failures or unsupported videos are handled.

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 a single short sentence that immediately communicates the action and resource. It contains no filler, repeated schema information, or unnecessary clauses, 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?

For a simple one-parameter tool, the core purpose and input are clear enough for basic selection and invocation. However, with no annotations and no output schema, the description leaves meaningful gaps around return behavior, prerequisites, and platform limitations, so it is only minimally complete.

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% and the single 'url' parameter is already described as 'YouTube视频链接'. The description's phrase '根据视频链接' restates the parameter without adding extra meaning such as accepted URL formats, video type restrictions, or size/length constraints.

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 action ('下载'/download), a specific resource ('YouTube视频'/YouTube video), and the required input ('视频链接'/video link). This clearly separates it from platform-specific siblings like bilibili-video-downloader and from non-download YouTube tools like youtube-comment or youtube-digest.

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 implies the main usage context: use this when a user supplies a YouTube video link and wants the video downloaded. However, it does not explicitly mention alternatives or say when not to use it, such as for bilibili, Instagram, TikTok, or other platform links, so the guidance remains implicit rather than explicit.

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