delete_observations

THE RISK

Critical Risk

Why delete_observations needs a policy

Deleting observations from a knowledge graph that serves as persistent memory for chat applications permanently removes stored user information. This action cannot be undone and constitutes data loss. While not as severe as a critical system wipe, it is destructive in nature and warrants 'high' severity because it irreversibly modifies the user's memory store, which is the core function of this MCP server.

From the tool's definition Tool name is 'delete_observations' with description 'Delete specific observations from entities in the knowledge graph' — the verb 'delete' indicates irreversible removal of data.

Documented attack patterns abuse exactly the kind of access delete_observations gives an agent:

POLICY

How to control delete_observations

PolicyLayer is an MCP gateway — it sits between your AI agents and Knowledge Graph Memory Server, and nothing reaches the server without passing your rules. This is the rule we recommend for delete_observations:

policy.json

{
  "version": "1",
  "default": "deny",
  "hide": [
    "delete_observations"
  ]
}

delete_observations disappears from the agent's tool list entirely, and any attempt to call it is denied. The rest of the server keeps working.

Create a free account and register Knowledge Graph Memory Server — nothing to install.
Add this policy — paste it, or build it visually.
Point your MCP client (Claude, Cursor, anything) at your gateway URL.

RESTRICT THIS TOOL →

Free to start. No card required.

EXPLORE

Related tools and policies

More Knowledge Graph Memory Server tools

Destructive delete_entities Delete multiple entities and their associated relations from the knowledge graph Destructive delete_relations Delete multiple relations from the knowledge graph Write add_observations Add new observations to existing entities in the knowledge graph Write create_entities Create multiple new entities in the knowledge graph Write create_relations Create multiple new relations between entities in the knowledge graph. Relations should be Read read_graph Read the entire knowledge graph Read search_nodes Search for nodes in the knowledge graph based on one or more keywords. The search covers e Read open_nodes Open specific nodes in the knowledge graph by their names. Returns the complete node infor

All 9 Knowledge Graph Memory Server tools →

Destructive tools on other servers

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Go deeper

Critical-risk tools in Knowledge Graph Memory Server → Every critical-risk tool this server exposes, in one view.
All critical-risk MCP tools → Every critical-risk tool across the catalogue, and the policy pattern that contains them.
The MCP Attack Database → Documented attack patterns against MCP deployments — and the policies that stop them.
Blast radius → How much damage one compromised or confused agent can do — and how to bound it.
Tool call approval → Approval gates on individual tool calls: auto-allow, prompt, or deny.
Rate Limiting MCP Tool Calls: A Practical Guide →
MCP Security: Why Prompt Guardrails Aren't Enough →

FAQ

Questions about delete_observations

What does the delete_observations tool do? +

Delete specific observations from entities in the knowledge graph. It is categorised as a Destructive tool in the Knowledge Graph Memory Server MCP Server, which means it can permanently delete or destroy data. Block by default and require explicit approval.

How do I enforce a policy on delete_observations? +

Register the Knowledge Graph Memory Server MCP server in PolicyLayer and add a rule for delete_observations: 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 Knowledge Graph Memory Server. Nothing to install.

What risk level is delete_observations? +

delete_observations is a Destructive tool with critical risk. Critical-risk tools should be blocked by default and only enabled with explicit human approval.

Can I rate-limit delete_observations? +

Yes. Add a rate_limit block to the delete_observations 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.

How do I block delete_observations completely? +

Set action: deny in the PolicyLayer policy for delete_observations. 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.

What MCP server provides delete_observations? +

delete_observations is provided by the Knowledge Graph Memory Server MCP server (yodakeisuke/mcp-memory-domain-knowledge). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.

Enforce policy on every Knowledge Graph Memory Server tool call.

Start from Knowledge Graph Memory Server, add the rest of your stack, and see everything your agents can call. Then put policy on all of it.

CHECK YOUR STACK →