refresh_mounts | PolicyLayer

WHAT IT DOES

What refresh_mounts does on Hammerspace Storage Management MCP Server

AI agents invoke refresh_mounts to trigger actions in Hammerspace Storage Management MCP Server. What it does depends on the arguments the agent supplies, and its effects often reach beyond the immediate call — builds kicked off, notifications sent, workflows started.

WHY IT NEEDS A POLICY

Why refresh_mounts needs a policy

Refreshing NFS mounts is an operational action that remounts or re-establishes filesystem mounts. It is not a passive read, nor does it irreversibly delete data, but it executes a system-level operation that can disrupt active file access, cause transient I/O errors, or affect running workloads.

From the tool's definition 'Refresh Hammerspace NFS mounts to fix stale file handles' — actively triggers a mount refresh operation on NFS mounts

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

refresh_mounts Rate-limited

refresh_mounts stays usable, but rate-capped — a runaway agent can't fire it dozens of times 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_mounts": {
      "limits": [
        {
          "counter": "refresh_mounts_rate",
          "window": "minute",
          "max": 10,
          "scope": "grant"
        }
      ]
    }
  }
}

RATE-LIMIT THIS TOOL →

Instant setup, no code required.

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

FAQ

Questions about refresh_mounts

What does the refresh_mounts tool do? +

Refresh Hammerspace NFS mounts to fix stale file handles. It is categorised as a Execute tool in the Hammerspace Storage Management MCP Server MCP Server, which means it can trigger actions or run processes. Use rate limits and argument validation.

How do I enforce a policy on refresh_mounts? +

Register the Hammerspace Storage Management MCP Server MCP server in PolicyLayer and add a rule for refresh_mounts: 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 Hammerspace Storage Management MCP Server. Nothing to install.

What risk level is refresh_mounts? +

refresh_mounts is a Execute tool with high risk. Execute tools should be rate-limited and have argument validation enabled.

Can I rate-limit refresh_mounts? +

Yes. Add a rate_limit block to the refresh_mounts 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_mounts completely? +

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

refresh_mounts is provided by the Hammerspace Storage Management MCP Server MCP server (mbloomhammerspace/mcp-1.5-main). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.