download_video

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

With no annotations provided, the description carries full burden for behavioral disclosure. It states the basic action (download video) but doesn't describe what happens during execution: whether it's synchronous/asynchronous, if it creates background tasks, error handling, file system impacts, or performance characteristics. For a tool with 8 parameters and no annotation coverage, this leaves significant behavioral gaps.

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, efficient Chinese sentence that directly states the tool's purpose without unnecessary words. It's appropriately sized for a download tool and front-loads the core functionality. Every word earns its place with zero waste.

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 complex video download tool with 8 parameters, no annotations, and no output schema, the description is inadequate. It doesn't explain what the tool returns (success/failure indicators, file paths, task IDs), doesn't mention behavioral aspects like async processing (suggested by sibling task tools), and provides minimal context beyond the basic action. The description should do more given the tool's complexity.

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%, so the schema already documents all 8 parameters thoroughly with descriptions, defaults, enums, and required status. The description adds no parameter-specific information beyond what's in the schema. Baseline 3 is appropriate when schema does all the parameter documentation work.

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 clearly states the action ('下载' meaning download) and target resource ('指定URL的视频'), specifying it downloads video from a URL to a local path. It distinguishes from siblings like get_video_info (info retrieval) and list_tasks (task listing), but doesn't explicitly differentiate from cancel_task or get_task_status which are task management tools. The purpose is clear but sibling differentiation is implicit rather than explicit.

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 provides no guidance on when to use this tool versus alternatives. While it's obvious this is for downloading videos (unlike get_video_info for info retrieval), there's no mention of prerequisites, constraints, or when to choose other tools like cancel_task for task management. Usage context is implied but not explicitly stated.

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