Extract and save a single video frame at a chosen timestamp as PNG or JPEG for thumbnails or previews.
Save one frame of a video as a PNG or JPEG, at a time in seconds.
| Name | Required | Description | Default |
|---|---|---|---|
| overwrite | No | ||
| timestamp | No | ||
| input_path | Yes | ||
| output_path | Yes |
| Name | Required | Description | Default |
|---|---|---|---|
| output_path | Yes | ||
| output_bytes | Yes | ||
| timestamp_seconds | Yes |
Changes observed during successful MCP inspections.
v0.3.0Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already declare write and destructive behavior. The description adds useful context that the operation saves a frame at a timestamp and supports PNG/JPEG, but it does not explain overwrite behavior or what happens to an existing output file.
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 with no wasted words. It conveys the core action and the key timestamp unit efficiently.
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 output schema covers return values, and annotations cover the destructive write profile. Still, for a file-writing tool with undocumented parameters, the description should explain overwrite semantics and how the output format is selected.
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?
With 0% schema description coverage, the description partially compensates by clarifying that timestamp is in seconds and that output can be PNG or JPEG. However, it does not explain the overwrite parameter or output format determination, leaving meaningful gaps.
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: saving one video frame as a PNG or JPEG. It clearly distinguishes video frame extraction from image-oriented siblings, though it does not explicitly contrast with video_info.
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 alternatives such as video_info or image_thumbnail. The description implies extraction use but gives no conditions, prerequisites, or exclusions.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.