update_host · Defined MCP: Risk & Policy

WHAT IT DOES

What update_host does on Defined

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

WHY IT NEEDS A POLICY

Why update_host needs a policy

The tool name 'update_host' clearly indicates modification of host records/configuration. Given the server's purpose (network administration) and the presence of related tools that create/block hosts, this is a Write operation—it modifies network infrastructure state reversibly. Severity is high because misuse could alter firewall rules, network routing, or host configurations affecting multiple network endpoints.

From the tool's definition Tool name is 'update_host' with empty description. In context of 'managing Defined Networking infrastructure' and sibling tools like 'create_host', 'block_host', 'add_firewall_rule', this tool creates or modifies host configuration reversibly.

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

update_host Rate-limited

update_host 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": {
    "update_host": {
      "limits": [
        {
          "counter": "update_host_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 Defined, so you can run agents against it safely.

FAQ

Questions about update_host

What does the update_host tool do? +

update_host. It is categorised as a Write tool in the Defined MCP Server, which means it can create or modify data. Consider rate limits to prevent runaway writes.

How do I enforce a policy on update_host? +

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

What risk level is update_host? +

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

Can I rate-limit update_host? +

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

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

update_host is provided by the Defined MCP server (quickvm/defined-mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.