save_video

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

No annotations are present, so the description must carry behavioral context. It adds a useful disclosure that authentication is handled internally and the API key is not exposed, but it omits other behavioral details such as overwrite behavior or what happens if the video is not yet complete.

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?

Two concise sentences front-load the purpose and add a relevant security detail. No wasted words, though 'Download and save' is slightly redundant but acceptable.

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?

With no output schema, the description should at least hint at return behavior, but it does not. It also fails to clarify how this tool differs from 'download_video', leaving a significant selection gap despite adequate schema coverage.

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?

The input schema has 100% description coverage for all three parameters, including the variant enum and output_path default. The description adds no parameter-level detail, so the schema carries the burden; baseline 3 is appropriate.

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?

Description uses a specific verb ('Download') and identifies the object ('a completed video' saved 'to a local file'), making the core action clear. However, it does not distinguish itself from the sibling tool 'download_video', so it lacks sibling differentiation.

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 phrase 'completed video' implies it should be used only after the video has finished processing, and 'handles authentication internally' suggests a reason to prefer it. But there is no explicit when-not or alternative comparison, especially with the sibling download_video.

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