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.
Input schema / properties / start / x-uiAdded value: +{
+ "pair_joint": "to",
+ "pair_label": "Part to keep",
+ "pair_with": "end"
+}Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations only provide readOnlyHint=false and destructiveHint=false. The description adds the key behavioral fact 'without re-encoding', which indicates a lossless operation. While the schema description for the file parameter elaborates on stream copy and keyframe alignment, the description itself contributes a meaningful trait beyond 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 efficiently conveys the action, resource, and key behavioral trait. It includes a category tag and no filler, making it optimally concise.
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 simple trim tool with a thorough schema, the description covers the core function and the lossless aspect. It does not mention output or return behavior, but the absence of an output schema is not a significant gap given the schema's completeness. Overall, it is sufficiently informative for an agent to call correctly.
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 explanations for all three parameters (end, file, start), including defaults and constraints. The description adds no additional parameter-specific meaning beyond summarizing 'start and end time', so it rests at the baseline for high schema coverage.
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 clearly states the verb 'Trim' and the resource 'video clip' with specific start/end times. The phrase 'without re-encoding' distinguishes it from compression or conversion tools, making its purpose unambiguous among many sibling media tools.
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 implies a use case (lossless trimming) but does not explicitly contrast with alternatives like media_trim_audio or media_compress_video. It lacks explicit when-to-use or when-not-to-use guidance, though the 'without re-encoding' hint gives some direction.
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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