AI agents use update_note to create or update resources in Open WebUI MCP Server — usually the action step of a workflow, after the agent has gathered context. Every call changes real data in your Open WebUI MCP Server environment.
This tool falls under Write because it creates or modifies data reversibly. Notes can be updated and reverted, making this a modification rather than a destructive or read-only operation. Severity is medium because a malicious agent could modify notes containing important information, but the impact is limited to notes rather than system-critical data or irreversible actions.
From the tool's definition update_note updates a note's title or content, which is a reversible modification of data. The description explicitly states 'Update a note's title or content,' indicating a write operation that modifies existing data.
Documented attack patterns abuse exactly the kind of access update_note gives an agent:
PolicyLayer is an MCP gateway — it sits between your AI agents and Open WebUI MCP Server, and nothing reaches the server without passing your rules. This is the rule we recommend for update_note:
{
"version": "1",
"default": "deny",
"tools": {
"update_note": {
"limits": [
{
"counter": "update_note_rate",
"window": "minute",
"max": 30,
"scope": "grant"
}
]
}
}
}update_note 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.
Update a note's title or content. It is categorised as a Write tool in the Open WebUI MCP Server MCP Server, which means it can create or modify data. Consider rate limits to prevent runaway writes.
Register the Open WebUI MCP Server MCP server in PolicyLayer and add a rule for update_note: 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 Open WebUI MCP Server. Nothing to install.
update_note 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 update_note 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 update_note. 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.
update_note is provided by the Open WebUI MCP Server MCP server (troylar/open-webui-mcp-server). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
Start from Open WebUI MCP Server, add the rest of your stack, and see everything your agents can call. Then put policy on all of it.
Free to start. No card required.
82 Open WebUI MCP Server tools catalogued and risk-classified — across an index of 43,000+ MCP servers.