Set a video clip's opacity percentage (0–100) and verify the readback value.
Set the Opacity percentage (0 to 100) on a video clip and verify the readback value.
| Name | Required | Description | Default |
|---|---|---|---|
| opacity | Yes | Opacity value between 0 and 100. | |
| clip_name | No | Clip name. | |
| clip_index | No | 0-based clip index. | |
| track_type | No | video | |
| track_index | No | 0-based video track index. | |
| clip_node_id | No | Timeline clip nodeId. |
Changes observed during successful MCP inspections.
v1.0.0Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
With no annotations, the description carries the full burden. It does disclose a genuine behavioral trait beyond the schema: the tool verifies the readback value after writing. However, it says nothing about failure behavior, idempotency, or what a failed verification means.
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?
A single sentence with zero filler, with the action and target front-loaded before the verification clause.
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?
There are no annotations and no output schema, so the description must explain the return side; it gestures at this by mentioning readback verification but never says what value or format comes back. The ambiguity of six parameters offering three alternate clip-identification routes is also left unresolved.
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 coverage is 83% and every meaningful parameter is documented, so the baseline is 3. The description only restates the opacity range already in the schema and adds no guidance on how clip_name, clip_index, and clip_node_id interact when locating the target clip.
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 and resource ('Set the Opacity percentage... on a video clip') plus the value domain (0 to 100), which separates it from the motion siblings (set_motion_position/scale/rotation) and set_supported_blend_mode. It stops short of clarifying why an agent would pick it over the generic set_supported_clip_property, which could plausibly also set opacity.
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?
No when-to-use context, no prerequisites, and no mention of the overlapping generic setter (set_supported_clip_property) or of read_clip_properties for inspection. The agent has to infer context from the name and sibling list.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.