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

With no annotations the description carries the full burden, and it discloses key traits: credit cost (10 credits per started 10s), asynchronous polling, an input-type restriction, and live preview rendering. It omits auth/permission requirements and any failure modes, keeping it short of a 5.

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?

Purpose is front-loaded, followed by cost, input constraint, and polling instruction in a compact sequence. Every sentence carries distinct operational information with no 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?

For a 2-param generation tool with no output schema and no annotations, the description covers cost, async workflow, input constraints, a fallback tool, and rendering behavior. Nothing an agent needs to invoke it correctly is missing.

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 100%, so the 3 baseline applies, but the description adds real meaning for videoUrl beyond the schema's generic 'Direct URL of the video file': it must be a direct file URL (e.g. .mp4) and page links are invalid. The 'name' parameter is left to the schema.

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 names a specific verb ('remove') and a precise set of resources ('burned-in subtitles, captions, watermarks, logos or on-screen text from a video'), with an alternative alias '(Subtitle Remover)'. An agent can distinguish this from siblings like create_video or upscale_video without opening the schema.

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?

It gives an explicit when-not ('page links (YouTube, TikTok) don't work') and an alternative tool with its condition ('use upload_file first for a file the user provides'), plus the follow-up action ('poll with wait_for_video'). The routing is unambiguous.

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