invalidate_edge

THE RISK

Critical Risk

Why invalidate_edge needs a policy

Invalidating a graph edge modifies the temporal knowledge graph in a way that removes or marks as invalid existing relationship data. This is likely irreversible — once an edge is invalidated in a temporal knowledge graph, the validity window is closed and cannot be restored to its previous state.

From the tool's definition Explicitly invalidates a graph edge when it is discovered to be stale or incorrect

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

POLICY

How to control invalidate_edge

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

policy.json

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

invalidate_edge 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 Memex — 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 Memex tools

Write record_decision Creates a Decision node in the graph. Call this when making or discovering architectural c Write record_problem Creates a Problem node in the graph. Call this when discovering bugs or technical debt. Re Write resolve_problem Marks a Problem as closed and records the resolution. Returns a status string. Read explain_change Cross-references a git commit Read get_context_briefing Returns a ranked, token-capped briefing of the most important Read get_open_problems Returns currently open technical problems and TODOs sorted by severity as a Markdown strin Read get_project_context Returns a compressed briefing of the project as a Markdown string: active modules, recent Read get_recent_decisions Returns architectural and technical decisions from the past N days as a Markdown string.

All 13 Memex tools →

Destructive tools on other servers

Android Forensics ADB MCP Server create_full_backup 0xarchive web3_revoke_key Frida Game Hacking MCP clear_scan cPanel MCP Server clear_spam_box

Go deeper

Critical-risk tools in Memex → 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 invalidate_edge

What does the invalidate_edge tool do? +

Explicitly invalidates a graph edge when it is discovered to be stale or incorrect. Returns a status string. It is categorised as a Destructive tool in the Memex 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 invalidate_edge? +

Register the Memex MCP server in PolicyLayer and add a rule for invalidate_edge: 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 Memex. Nothing to install.

What risk level is invalidate_edge? +

invalidate_edge 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 invalidate_edge? +

Yes. Add a rate_limit block to the invalidate_edge 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 invalidate_edge completely? +

Set action: deny in the PolicyLayer policy for invalidate_edge. 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 invalidate_edge? +

invalidate_edge is provided by the Memex MCP server (stifler7/memex). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.

Enforce policy on every Memex tool call.

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

CHECK YOUR STACK →