auth_refresh · Evaluar MCP Server MCP: Risk & Policy

WHAT IT DOES

What auth_refresh does on Evaluar MCP Server

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

WHY IT NEEDS A POLICY

Why auth_refresh needs a policy

This tool performs a write-like operation on the user's authentication session state. While not destructive or permanent, refreshing a token creates a new/updated credential artifact. However, the severity is medium rather than high because token refresh is a standard, reversible operation with limited blast radius—a refreshed token doesn't directly access or modify business data on its own.

From the tool's definition The tool description states it 'Refresh the authentication token', which modifies the current authentication state by generating or updating a token credential.

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

auth_refresh Rate-limited

auth_refresh 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": {
    "auth_refresh": {
      "limits": [
        {
          "counter": "auth_refresh_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 Evaluar MCP Server, so you can run agents against it safely.

FAQ

Questions about auth_refresh

What does the auth_refresh tool do? +

Refresh the authentication token. Use this when the current token is about to expire. It is categorised as a Write tool in the Evaluar MCP Server MCP Server, which means it can create or modify data. Consider rate limits to prevent runaway writes.

How do I enforce a policy on auth_refresh? +

Register the Evaluar MCP Server MCP server in PolicyLayer and add a rule for auth_refresh: 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 Evaluar MCP Server. Nothing to install.

What risk level is auth_refresh? +

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

Can I rate-limit auth_refresh? +

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

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

auth_refresh is provided by the Evaluar MCP Server MCP server (yarmijosp94/evaluar-mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.