两个视频叠加，注意不是拼接长度，而是画中画效果 参数： background_video(str) - 背景视频文件的路径。 overlay_video(str) - 前景视频文件路径。 output_path(str) - 输出路径 position(enum) - 相对位置，TopLeft=1: 左上角,TopCenter=2: 上居中, TopRight=3: 右上角 RightCenter=4: 右居中 BottomRight=5: 右下角 BottomCenter=6: 下居中 BottomLeft=7: 左下角 LeftCenter=8: 左居中 Center=9: 居中 d...
AI agents use overlay_video to create or update resources in FFmpeg-MCP Server — usually the action step of a workflow, after the agent has gathered context. Every call changes real data in your FFmpeg-MCP Server environment.
This tool composites two videos into a new output file (picture-in-picture). It creates a new file at output_path without deleting source files, making it a Write operation. Misuse could overwrite existing files if output_path points to an existing file, but the primary action is creation/modification, not irreversible destruction.
From the tool's definition 两个视频叠加，注意不是拼接长度，而是画中画效果 (two videos overlaid, picture-in-picture effect); output_path parameter writes a new file
Documented attack patterns abuse exactly the kind of access overlay_video gives an agent:
PolicyLayer is an MCP gateway — it sits between your AI agents and FFmpeg-MCP Server, and nothing reaches the server without passing your rules. This is the rule we recommend for overlay_video:
{
"version": "1",
"default": "deny",
"tools": {
"overlay_video": {
"limits": [
{
"counter": "overlay_video_rate",
"window": "minute",
"max": 30,
"scope": "grant"
}
]
}
}
}overlay_video stays usable, but capped — an agent stuck in a loop can't make hundreds of changes a minute. Everything else on the server is denied unless you say otherwise.
Free to start. No card required.
两个视频叠加，注意不是拼接长度，而是画中画效果 参数： background_video(str) - 背景视频文件的路径。 overlay_video(str) - 前景视频文件路径。 output_path(str) - 输出路径 position(enum) - 相对位置，TopLeft=1: 左上角,TopCenter=2: 上居中, TopRight=3: 右上角 RightCenter=4: 右居中 BottomRight=5: 右下角 BottomCenter=6: 下居中 BottomLeft=7: 左下角 LeftCenter=8: 左居中 Center=9: 居中 dx(int) - 整形,前景视频坐标x偏移值 dy(int) - 整形,前景视频坐标y偏移值. It is categorised as a Write tool in the FFmpeg-MCP Server MCP Server, which means it can create or modify data. Consider rate limits to prevent runaway writes.
Register the FFmpeg-MCP Server MCP server in PolicyLayer and add a rule for overlay_video: allow, deny, rate-limit, or require approval. Point your MCP client at the PolicyLayer proxy URL and the rule is enforced on every call, before it reaches FFmpeg-MCP Server. Nothing to install.
overlay_video is a Write tool with medium risk. Write tools should be rate-limited to prevent accidental bulk modifications.
Yes. Add a rate_limit block to the overlay_video rule in your PolicyLayer policy. For example, setting max: 10 and window: 60 limits the tool to 10 calls per minute. Rate limits are tracked per agent session and reset automatically.
Set action: deny in the PolicyLayer policy for overlay_video. The AI agent will receive a policy violation error and cannot call the tool. You can also include a reason field to explain why the tool is blocked.
overlay_video is provided by the FFmpeg-MCP Server MCP server (video-creator/ffmpeg-mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
Deterministic rules across all 8 FFmpeg-MCP Server tools. Per-identity grants. Full audit log. Live in minutes. Nothing to install.
Free to start. No card required.
8 FFmpeg-MCP Server tools catalogued and risk-classified — across an index of 42,500+ MCP servers.