capcut_add_subtitles

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

No annotations are provided, so the description carries the full burden of behavioral disclosure. It only says 'batch adds' and does not explain side effects such as whether existing subtitles are replaced or appended, whether a project or media must exist first, or what happens when multiple subtitle sources are provided. This lack of behavioral context is a meaningful gap for a mutation tool.

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, tightly worded sentence that front-loads the core action and the main input alternatives. Every phrase contributes useful information, and there is no redundant or filler content.

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 no-annotation mutation tool with nine parameters and no output schema, the description is too thin. It omits operational context such as how multiple input sources are resolved, whether the operation appends or replaces existing subtitles, and what the expected result or return value is. The parameter schema covers parameter semantics but not the operation-level details needed for confident 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 100%, so the baseline is 3. The description adds value by grouping the optional-input parameters into three meaningful modes: structured array, SRT file path, or raw SRT string. This clarifies that these parameters are alternative sources, which is not obvious from the schema alone, though it does not specify precedence if more than one is supplied.

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 ('batch adds'), a clear resource ('synchronized subtitles / captions'), and the three supported input forms: array items, SRT file path, or raw SRT string. This makes the tool's function immediately evident and distinguishes it from sibling tools like capcut_add_text or capcut_add_viral_caption by emphasizing batch synchronization.

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 clearly implies when this tool is appropriate: when subtitles need to be added in batch from structured cues, an SRT file, or raw SRT text. However, it does not explicitly mention alternatives or state when not to use it, such as for a single text overlay.

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