capcut_add_video

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

No annotations are provided, so the description carries the full behavioral burden. It does add one meaningful fact: the operation is a session edit and requires capcut_save to persist. However, it does not disclose whether clips are inserted vs replaced, how track selection behaves, or any side effects on existing clips.

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 front-loaded sentence with no wasted words. The core action and the persistence requirement are both stated efficiently. It is slightly too terse given the tool's complexity, but as conciseness alone it is well structured.

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?

This is a complex 14-parameter tool with no annotations and no output schema, and the description leaves most operational behavior unstated. An agent is not told how omitted tracks are handled beyond the schema, what the default duration means, or what happens on success/failure. The session-save note helps but is far from enough for safe invocation.

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 only 36%, and the description provides no parameter-level meaning whatsoever. With 14 parameters and 12 undocumented, an agent cannot understand how file, posX, posY, scale, speed, volume, opacity, rotation, or trackRenderIndex behave. The description must compensate for the schema gaps and does not.

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 verb ('Add'), the resource ('a video clip'), and the target ('on a track'). It also distinguishes this tool from siblings like capcut_add_image, capcut_add_audio, and capcut_add_text by naming the media type explicitly.

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?

There is no guidance about when to choose this tool over alternatives. With 27 siblings, including several other add_* tools, the description gives no exclusions, no alternative names, and no conditions for selecting it. The media-type naming implies some distinction, but the tool never says 'use this for video clips instead of add_image/add_audio'.

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