Trim Video — Trim a video clip to a specified start and end time without re-encoding. [category: media]
| Name | Required | Description | Default |
|---|---|---|---|
| end | No | End time. Omit to trim to the end of the file; when set it must be after start. | |
| file | Yes | Video to trim. Stream copy — output keeps this container/codec, and the cut starts at the keyframe at or before `start`. | |
| start | No | Start time e.g. '00:00:10'. Defaults to the beginning. | 0 |
Changes observed during successful MCP inspections.
Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
The 'without re-encoding' phrase adds a meaningful behavioral trait beyond the annotations, implying stream-copy behavior and keyframe-aligned cuts. However, the description does not state what the tool returns or how it handles the output file, and there is no contradiction with the provided annotations.
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, front-loaded sentence that immediately states the tool's title and purpose. There is no filler or redundant information; the category tag is minimal and unobtrusive.
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?
The input parameters are fully documented in the schema and the annotations cover the safety profile, so an agent can select and invoke the tool correctly. The only minor gap is the lack of an explicit description of the return value, but for a trim operation the result is reasonably inferable and not needed for 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%, with detailed descriptions for file, start, and end, so the description does not need to repeat parameter meaning. The description's mention of 'specified start and end time' aligns cleanly with the schema but adds no new semantic detail.
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 names a specific operation ('Trim'), a specific resource ('a video clip'), and the control parameters ('specified start and end time'). The qualifier 'without re-encoding' helps distinguish this from convert/compress video tools, making the purpose unambiguous.
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 gives clear context for when to use the tool: when a video clip needs trimming to a start/end time without re-encoding. It does not explicitly name siblings like media_trim_audio or exclusion conditions, so it stops short of full alternative guidance.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.
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