Updates an existing knowledge node. Use to modify content, tags, importance, or visibility of a node. Supports partial updates - only specified fields are changed.
AI agents use kg_update_node to create or update resources in Personal Kg — usually the action step of a workflow, after the agent has gathered context. Every call changes real data in your Personal Kg environment.
This is a Write operation because it creates or modifies data reversibly. It updates existing knowledge nodes (the data structure underlying this knowledge graph system) but does not delete or irreversibly destroy data, nor does it execute arbitrary code or trigger external operations. The changes are reversible through subsequent updates.
From the tool's definition kg_update_node updates an existing knowledge node, allowing modification of content, tags, importance, or visibility. The description explicitly states 'modifies content' and supports 'partial updates' of node properties.
Documented attack patterns abuse exactly the kind of access kg_update_node gives an agent:
PolicyLayer is an MCP gateway — it sits between your AI agents and Personal Kg, and nothing reaches the server without passing your rules. This is the rule we recommend for kg_update_node:
{
"version": "1",
"default": "deny",
"tools": {
"kg_update_node": {
"limits": [
{
"counter": "kg_update_node_rate",
"window": "minute",
"max": 30,
"scope": "grant"
}
]
}
}
}kg_update_node 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.
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Updates an existing knowledge node. Use to modify content, tags, importance, or visibility of a node. Supports partial updates - only specified fields are changed. It is categorised as a Write tool in the Personal Kg MCP Server, which means it can create or modify data. Consider rate limits to prevent runaway writes.
Register the Personal Kg MCP server in PolicyLayer and add a rule for kg_update_node: 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 Personal Kg. Nothing to install.
kg_update_node 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 kg_update_node 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 kg_update_node. 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.
kg_update_node is provided by the Personal Kg MCP server (tomschell/personal-kg-mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
Start from Personal Kg, 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.
18 Personal Kg tools catalogued and risk-classified — across an index of 43,000+ MCP servers.