Remove a relationship between two entities from the knowledge graph
AI agents call delete_relation to permanently remove resources in Lightrag — typically in cleanup and lifecycle workflows. It does its job in a single call, and there is no undo.
This tool permanently deletes data (relationships in a knowledge graph). Deletion operations are classified as Destructive per the schema rules. The severity is high because deleting relationships could break data integrity and knowledge graph consistency, affecting downstream queries and analyses that depend on those relationships.
From the tool's definition Tool name is 'delete_relation' and description states 'Remove a relationship between two entities from the knowledge graph' - this is an irreversible deletion operation that cannot be undone.
Attacks that exploit this kind of access
Remove a relationship between two entities from the knowledge graph. It is categorised as a Destructive tool in the Lightrag MCP Server, which means it can permanently delete or destroy data. Block by default and require explicit approval.
Register the Lightrag MCP server in PolicyLayer and add a rule for delete_relation: 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 Lightrag. Nothing to install.
delete_relation is a Destructive tool with critical risk. Critical-risk tools should be blocked by default and only enabled with explicit human approval.
Yes. Add a rate_limit block to the delete_relation 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 delete_relation. 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.
delete_relation is provided by the Lightrag MCP server (lightrag-mcp). 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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