Download a finished Seedance video

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

With no annotations provided, the description fully carries the burden. It discloses critical behaviors: output URLs expire after 24 hours and allow only 100 downloads (no reissue), the tool looks up the current URL itself, file is written to current directory if no path given, existing files are never overwritten unless overwrite=true, and include_last_frame requires the task to have been created with return_last_frame.

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 about 100 words, well-structured with the primary purpose first, followed by usage context and parameter details. Every sentence adds value, no redundancy or filler.

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?

Given the 4 parameters and full schema coverage, the description is complete. It explains prerequisites (task must be succeeded, within 24h), file handling rules, optional behavior (include_last_frame condition), and the self-service nature of URL resolution. An output schema exists but the description correctly focuses on usage context rather than return 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 description coverage is 100%, giving a baseline of 3. The description adds value beyond the schema by explaining that output_path defaults to current directory for <task_id>.mp4, that existing files are never overwritten without explicit overwrite=true, and that include_last_frame requires the original task to have return_last_frame. These details clarify default behavior and preconditions not obvious from parameter descriptions alone.

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 tool saves a finished Seedance video to a local file, with the specific verb 'Save' and resource 'finished Seedance video'. It distinguishes from siblings like seedance_get_video (just view link) by explaining when to use it for permanent storage rather than just seeing a link.

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 explicitly says to use this when the user wants to keep the video rather than just a link, and mentions URL expiration and download limits. It also states the task must be in 'succeeded' state. While it doesn't explicitly name alternative tools, the context of sibling names and the 'use this whenever' phrasing provides clear guidance.

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