update_constitution · Mcp Vibe Check MCP: Risk & Policy

WHAT IT DOES

What update_constitution does on Mcp Vibe Check

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

WHY IT NEEDS A POLICY

Why update_constitution needs a policy

The tool creates or modifies data (constitutional rules) for the session. Since modifications are in-memory and session-scoped, they are reversible and not permanent, placing this in Write rather than Destructive. Severity is medium because altering constitutional rules could influence AI agent behavior and decision-making within the session, but impact is limited to current session scope.

From the tool's definition Tool description states 'Append a constitutional rule for this session (in-memory)' — explicitly modifies session state by adding rules, which is a reversible write operation.

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

update_constitution Rate-limited

update_constitution 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_constitution": {
      "limits": [
        {
          "counter": "update_constitution_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 Mcp Vibe Check, so you can run agents against it safely.

FAQ

Questions about update_constitution

What does the update_constitution tool do? +

Append a constitutional rule for this session (in-memory). It is categorised as a Write tool in the Mcp Vibe Check 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_constitution? +

Register the Mcp Vibe Check MCP server in PolicyLayer and add a rule for update_constitution: 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 Mcp Vibe Check. Nothing to install.

What risk level is update_constitution? +

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

Can I rate-limit update_constitution? +

Yes. Add a rate_limit block to the update_constitution 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_constitution completely? +

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

update_constitution is provided by the Mcp Vibe Check MCP server (vinny1575/vibe-check-mcp-server). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.