lexq_facts_update · LexQ MCP: Risk & Policy

WHAT IT DOES

What lexq_facts_update does on LexQ

AI agents use lexq_facts_update to create or update resources in LexQ — usually the action step of a workflow, after the agent has gathered context. Every call changes real data in your LexQ environment.

WHY IT NEEDS A POLICY

Why lexq_facts_update needs a policy

This tool modifies existing fact definitions in the business rules system, which constitutes a Write operation. It is reversible (facts can be updated again to previous states) and not destructive.

From the tool's definition Tool description explicitly states 'Update a fact definition' with constraints on what can be modified. The verb 'Update' and the nature of modifying fact definitions (business logic data) indicates a reversible write operation.

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

lexq_facts_update Rate-limited

lexq_facts_update 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.

View as policy code

policy.json

{
  "version": "1",
  "default": "deny",
  "tools": {
    "lexq_facts_update": {
      "limits": [
        {
          "counter": "lexq_facts_update_rate",
          "window": "minute",
          "max": 30,
          "scope": "grant"
        }
      ]
    }
  }
}

LIMIT THIS TOOL →

Instant setup, no code required.

PolicyLayer is an MCP gateway: every tool call is checked against your rule before it reaches LexQ, so you can run agents against it safely.

FAQ

Questions about lexq_facts_update

What does the lexq_facts_update tool do? +

Update a fact definition. Key and type cannot be changed. Only provided fields are updated. System facts only allow name and description changes. It is categorised as a Write tool in the LexQ MCP Server, which means it can create or modify data. Consider rate limits to prevent runaway writes.

How do I enforce a policy on lexq_facts_update? +

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

What risk level is lexq_facts_update? +

lexq_facts_update is a Write tool with medium risk. Write tools should be rate-limited to prevent accidental bulk modifications.

Can I rate-limit lexq_facts_update? +

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

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

lexq_facts_update is provided by the LexQ MCP server (lexq-io/lexq-cli). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.