capcut_add_video_clip

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

With no annotations, the description carries the full burden, and it partially delivers: it explains that smart_cutout activates native AI portrait background removal and that CapCut strips the background on open/export. However, it says nothing about whether the operation mutates/overwrites an existing draft, permission/auth needs, or ordering constraints with other add_* calls.

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?

Front-loads the core action, then uses a tight bulleted list for the two documented parameters. Efficient with no filler, though the bullets could be scannable one-liners rather than multi-line explanations.

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 10-parameter mutation tool with no annotations, the description is thin: it omits most parameters and all mutation side effects. An output schema exists, so return values need not be described, but the input-side gaps leave the agent under-informed about a complex insertion operation.

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 0% across 10 parameters, so the description must compensate, but it explains only 2 (smart_cutout, track_index). Key params like start_ms, duration_ms, source_start_ms, scale, transform_x/transform_y, and even the required draft_name/video_path receive no added meaning.

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?

States a specific verb+resource: 'Add a video or photo segment to the CapCut timeline.' An agent can tell this inserts visual media into the timeline, distinct from siblings like capcut_add_audio_clip or capcut_add_captions. It stops short of explicitly naming which sibling to prefer for overlays vs primary placement.

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 when-to-use guidance, no prerequisites (e.g. whether a draft must exist first), and no alternative routing. The track_index note ('0 for primary track, 1 for overlay/B-roll') hints at a usage decision but is framed as a parameter fact, not as guidance on choosing this tool.

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