Adds a marker to a specific timeline clip at a set time, with optional name, color, and comment for easy reference.
Add a marker to a specific clip on the timeline
| Name | Required | Description | Default |
|---|---|---|---|
| name | No | Marker name | |
| time | Yes | Time in seconds relative to clip start | |
| color | No | Marker color | |
| comment | No | Marker comment | |
| clipIndex | Yes | Clip index | |
| trackType | Yes | Track type | |
| trackIndex | Yes | Track index |
Changes observed during successful MCP inspections.
v1.0.0Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
No annotations are provided, so the description carries the full behavioral burden. It identifies the operation as an addition but does not disclose permissions, whether the marker persists or is undoable, index expectations, or what happens if the clip does not exist.
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?
It is a single front-loaded sentence with no wasted words. The action and target are immediately clear even if further detail is absent.
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 mutation tool with seven parameters, no annotations, and no output schema, the description is too thin. It does not explain index conventions, required permissions, return behavior, or how it relates to the other marker tools in the sibling list.
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 all seven parameters including time, trackType, trackIndex, and clipIndex are already documented in the schema. The description adds no additional meaning beyond that structured documentation.
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 verb and resource: 'Add a marker to a specific clip on the timeline.' This distinguishes it from sequence-level or project-item marker tools by scoping the marker to a clip, but it does not explicitly name the sibling alternatives like add_marker or add_project_item_marker.
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 guidance on when to use this tool versus add_marker, add_project_item_marker, or update_marker. The clip-specific scope is implied by 'specific clip,' but no conditions, exclusions, or alternatives are stated.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.