capcut_add_clip

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

With no annotations, the description carries the behavioral load and does so well: it discloses the side effect (file copied into <draft>/assets/), which formats have readable length/size, that fade_in_s/fade_out_s reuse the capcut_set_clip audio-fade writer, and that video clips copy audio_fade onto video material. The dry-run-by-default behavior is a critical safety disclosure, though it is left to the last sentence.

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 in the first sentence and every following sentence carries substance (side effects, format support, fade semantics, units, dry-run). It is slightly dense but contains 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 13-parameter mutation tool with no annotations and no output schema, the description covers purpose, side effects, format limitations and the dry-run default adequately. It could have said more about the write/return behavior in non-dry-run mode, but the essential call-time context is present.

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 already 92%, so the baseline is 3. The description adds genuine unit semantics ('Times are seconds') and cross-tool fade behavior, but it does not explain the majority of the 13 parameters (track layering, in_s vs start_s distinction, volume bounds), leaving most meaning 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?

States a specific verb (Add) and resource (video, image or audio file to a draft timeline), which is more granular than the sibling capcut_add_audio. However it does not explicitly contrast itself with siblings like capcut_add_audio or capcut_add_clip-adjacent tools, so an agent still has to infer the boundary.

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 never says when to use this tool versus alternatives, nor does it state prerequisites or exclusions. The cross-reference to capcut_set_clip concerns fade behavior, not usage routing. Nothing tells the agent when to prefer capcut_add_audio or capcut_add_effect instead.

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