set_youtube_watermark
Set (or remove) the BRANDING WATERMARK — the small subscribe badge overlaid on EVERY video on the channel, including ones uploaded later. One generated asset brands the whole channel at once, which is why it is worth doing before a batch of uploads rather than after. YouTube wants a SQUARE image,...
This record as markdown: /tools/hermoso/set-youtube-watermark.md
What set_youtube_watermark does on Hermoso
AI agents use set_youtube_watermark to create or update resources in Hermoso, usually the action step of a workflow, after the agent has gathered context. Every call changes real data in your Hermoso environment.
Why set_youtube_watermark is rated Medium
An AI agent can call set_youtube_watermark faster than any human can review: one bad instruction and it creates or modifies resources in Hermoso by the hundred, each call as confident as the last.
Risk signalsBulk/mass operation — affects multiple targets
Attacks that exploit this kind of access
The rule that runs set_youtube_watermark safely
PolicyLayer is an MCP gateway: it sits between your AI agents and Hermoso, and checks every tool call against a rule you set before the call runs. Nothing changes on the server itself. For set_youtube_watermark, this is the rule to start with:
set_youtube_watermark 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.
The button opens the PolicyLayer dashboard: create your workspace, connect Hermoso, apply this rule, and every set_youtube_watermark call is checked against it from then on.
Questions about set_youtube_watermark
Set (or remove) the BRANDING WATERMARK — the small subscribe badge overlaid on EVERY video on the channel, including ones uploaded later. One generated asset brands the whole channel at once, which is why it is worth doing before a batch of uploads rather than after. YouTube wants a SQUARE image, at least 150x150, under 10MB, and it renders SMALL: a full logo lockup with text will not read at that size. By default it shows for the whole video; timingType offsetFromStart/offsetFromEnd with offsetMs and durationMs narrows it. THE DATA API PUBLISHES NO WAY TO READ A WATERMARK BACK — there is only set and unset — so this reports. It is categorised as a Write tool in the Hermoso MCP Server, which means it can create or modify data. Consider rate limits to prevent runaway writes.
Register the Hermoso MCP server in PolicyLayer and add a rule for set_youtube_watermark: 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 Hermoso. Nothing to install.
set_youtube_watermark 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 set_youtube_watermark 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 set_youtube_watermark. 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.
set_youtube_watermark is provided by the Hermoso MCP server (https://app.hermoso.ai/mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
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