video_watch

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

With no annotations, the description carries the load well: it discloses statefulness (progress is persisted and can be cleared via cursor="stop"), the default chunk size, and that returns include point summaries plus a seen/total percentage and an explicit completion signal. It does not explain what the 'session' parameter does for progress isolation, which is a notable gap for a stateful tool.

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?

Front-loaded one-line summary followed by bulleted call patterns, so the important scoping and sequencing information is easy to scan. Slightly padded by the near-duplicate framing sentence ('一段一段看、看一点说一点'), but no bullet is wasted.

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 6-parameter stateful tool with no annotations and no output schema, the description covers call sequencing, mutation of stored progress, chunk sizing, and the shape of the return (progress percentage, completion notice). Remaining gaps are the session parameter and the lang/model knobs, which an agent may need to use correctly.

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%, so the description must compensate. It documents cursor's semantics (next/restart/stop) thoroughly and implies minutes via the '5 分钟' default, but leaves url, lang, model, and especially session unexplained.

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 specific action and resource: incremental, segmented viewing of a video that advances one chunk at a time (default 5 min, ~1k chars) and then stops for the caller to decide. It explicitly names the siblings it is not: video_window for verbatim text and video_brief(level="full") for a full pull.

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?

Gives an explicit call sequence — first call starts at 0, subsequent calls pass cursor="next", cursor="restart" rewinds, cursor="stop" clears progress — plus a clear exclusion ('do not use video_brief(level="full")') and a redirect to video_window. The when-to-use-vs-alternative mapping is fully spelled out.

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