refresh_cache · Mcp Proxy MCP: Risk & Policy

WHAT IT DOES

What refresh_cache does on Mcp Proxy

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

WHY IT NEEDS A POLICY

Why refresh_cache needs a policy

This tool modifies the cached tool definitions stored by the proxy server. While it does not delete or irreversibly destroy data (precluding Destructive), and it does not create new entries in a persistent system (Write rather than Execute), it does alter the state of the cache.

From the tool's definition The tool performs 'Force re-fetch' and 'update cache', which are write operations that modify cached state. The description uses language indicating mutation of the local cache state.

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

refresh_cache Rate-limited

refresh_cache 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": {
    "refresh_cache": {
      "limits": [
        {
          "counter": "refresh_cache_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 Proxy, so you can run agents against it safely.

FAQ

Questions about refresh_cache

What does the refresh_cache tool do? +

Force re-fetch tool definitions from a server (or all servers) and update cache. It is categorised as a Write tool in the Mcp Proxy MCP Server, which means it can create or modify data. Consider rate limits to prevent runaway writes.

How do I enforce a policy on refresh_cache? +

Register the Mcp Proxy MCP server in PolicyLayer and add a rule for refresh_cache: 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 Proxy. Nothing to install.

What risk level is refresh_cache? +

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

Can I rate-limit refresh_cache? +

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

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

refresh_cache is provided by the Mcp Proxy MCP server (shengxiao20/mcp-proxy-server). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.