capcut_auto_duck_bgm

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

With no annotations, the description must carry the full burden of behavior disclosure. It states the core volume-ducking behavior but does not mention that this modifies the timeline/BGM track, may overwrite existing volume automation, requires a saved draft, or whether the change is reversible.

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?

One focused sentence communicates the exact behavior without redundancy or filler. The core action is front-loaded and every part of the sentence contributes meaning.

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?

Although the parameter schema covers most inputs, the description is too thin given the lack of annotations and output schema. It does not clarify that the operation mutates the draft, requires saving via capcut_save, or what happens to existing manual volume keyframes, so the agent lacks important operational context.

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 83%, with baseVolume, duckVolume, bgmTrackIndex, fadeDurationSec, and speechTrackIndex documented. The description itself adds no parameter-specific meaning and leaves the required 'draft' parameter undocumented, but it does not need to repeat the schema, so 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?

The description states a specific action (automatically duck/lower) on a specific resource (BGM music volume) with clear conditions (during speech, raise during silence). This clearly distinguishes it from sibling audio tools such as capcut_set_audio_fade or capcut_normalize_audio.

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 intended use is implied by the description: call it when BGM should be automatically reduced under dialogue. However, it provides no explicit when-not-to-use guidance or comparison to alternatives like capcut_set_audio_fade, leaving the selection logic partly to inference.

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