video_meta

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

With no annotations, the description does carry real behavioral weight: "不下载任何媒体，几乎零成本" tells the agent this is a side-effect-free, low-latency read. However, it does not cover failure modes for private/geo-blocked videos, rate limits, or whether any network cost exists beyond 'almost zero'.

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?

Three short clauses ordered well: what it returns, then the cost/side-effect guarantee, then the decision it supports. Zero filler and the returned-field list 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?

There is no output schema, so the field enumeration in the description usefully doubles as the return-value contract. For a single-parameter read tool with no annotations, the only meaningful gap is the accepted URL format.

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 0% for the single `url` parameter, so the description must compensate; it only weakly does so via "公开视频", implying the URL must point at a publicly accessible video. No format examples (short link vs. full URL vs. BV id) are given.

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 concrete verb+resource: reads metadata of a public video, and enumerates the returned fields (title, uploader, duration, date, views/likes, subtitle presence). This field list effectively distinguishes it from siblings like video_subs or video_full, though it never names them explicitly.

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?

"用于判断这个视频值不值得看" implies a usage context (cheap pre-check before committing to heavier tools), but there is no explicit when-not guidance and no sibling is named as the alternative. An agent must infer that this is the triage step before video_full/video_watch.

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