Upload and set a custom thumbnail for a video. The image is streamed from a local file. The MIME type is inferred from the file extension (.png, .jpg/.jpeg, .gif, .bmp). Args - videoId (string, required): video to update the thumbnail for - imagePath (string, required): absolute path to the local...
AI agents use youtube_set_thumbnail to create or update resources in Youtube — usually the action step of a workflow, after the agent has gathered context. Every call changes real data in your Youtube environment.
This tool modifies existing video content (thumbnail) reversibly. A malicious agent could replace legitimate thumbnails with misleading, offensive, or deceptive images to manipulate viewer perception, damage channel reputation, or conduct social engineering. However, the action is reversible (a new thumbnail can be uploaded), so it is Write rather than Destructive.
From the tool's definition Tool 'uploads and sets a custom thumbnail for a video' — this modifies video metadata and presentation. Description explicitly states 'Upload and set' indicating a write/update operation to video properties.
Attacks that exploit this kind of access
Upload and set a custom thumbnail for a video. The image is streamed from a local file. The MIME type is inferred from the file extension (.png, .jpg/.jpeg, .gif, .bmp). Args - videoId (string, required): video to update the thumbnail for - imagePath (string, required): absolute path to the local image file Returns Short confirmation + thumbnail resource with URLs for all size variants. Examples - Set thumbnail: \. It is categorised as a Write tool in the Youtube MCP Server, which means it can create or modify data. Consider rate limits to prevent runaway writes.
Register the Youtube MCP server in PolicyLayer and add a rule for youtube_set_thumbnail: 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 Youtube. Nothing to install.
youtube_set_thumbnail 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 youtube_set_thumbnail 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 youtube_set_thumbnail. 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.
youtube_set_thumbnail is provided by the Youtube MCP server (tuitamogamer-gpt/youtube-mcp-server). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
Every MCP server has a record like this.
Type a name, get the same breakdown: verified identity, auth posture, risk grade, capabilities, recommended policy.
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