list_fields_vast

THE RISK

Low Risk

Why list_fields_vast needs a policy

This tool queries and returns metadata about available fields for commands. It performs data retrieval without modifying, creating, or deleting any resources. The metadata returned would be used to understand command structure, making it a classic Read operation with minimal risk if misused by an AI agent.

From the tool's definition Tool name and description indicate a retrieval operation: 'Get available fields for a command with metadata'. The verb 'Get' and the informational nature of returning field metadata describe a read-only query with no side effects.

Documented attack patterns abuse exactly the kind of access list_fields_vast gives an agent:

POLICY

How to control list_fields_vast

PolicyLayer is an MCP gateway — it sits between your AI agents and VAST Admin MCP Server, and nothing reaches the server without passing your rules. This is the rule we recommend for list_fields_vast:

policy.json

{
  "version": "1",
  "default": "deny",
  "tools": {
    "list_fields_vast": {}
  }
}

list_fields_vast is read-only, so it stays allowed — but everything else on the server is denied unless you say otherwise.

Create a free account and register VAST Admin MCP Server — nothing to install.
Add this policy — paste it, or build it visually.
Point your MCP client (Claude, Cursor, anything) at your gateway URL.

CAP THIS TOOL →

Free to start. No card required.

EXPLORE

Related tools and policies

More VAST Admin MCP Server tools

Execute create_support_bundle_vast Create a support bundle on a VAST cluster for diagnostics and troubleshooting Write create_clone_vast Create a clone from a snapshot Write create_quota_vast Create or update quota for a specific path and tenant Write create_snapshot_vast Create a snapshot for a VAST view Write create_view_from_template_vast Create a new VAST view from a predefined template Write create_view_vast Create a new VAST view Read describe_tool_vast Get tool schema with examples and accepted formats Read list_clusters_vast Retrieve information about configured VAST clusters

All 16 VAST Admin MCP Server tools →

Read tools on other servers

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Go deeper

The MCP Attack Database → Documented attack patterns against MCP deployments — and the policies that stop them.
Data exfiltration → How read access becomes an exfiltration channel when chained with untrusted content.
MCP token cost → What connecting this server costs in context-window tokens on every request.
Rate Limiting MCP Tool Calls: A Practical Guide →
MCP Security: Why Prompt Guardrails Aren't Enough →

FAQ

Questions about list_fields_vast

What does the list_fields_vast tool do? +

Get available fields for a command with metadata. It is categorised as a Read tool in the VAST Admin MCP Server MCP Server, which means it retrieves data without modifying state.

How do I enforce a policy on list_fields_vast? +

Register the VAST Admin MCP Server MCP server in PolicyLayer and add a rule for list_fields_vast: 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 VAST Admin MCP Server. Nothing to install.

What risk level is list_fields_vast? +

list_fields_vast is a Read tool with low risk. Read-only tools are generally safe to allow by default.

Can I rate-limit list_fields_vast? +

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

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

list_fields_vast is provided by the VAST Admin MCP Server MCP server (vast-data/vast-admin-mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.

Enforce policy on every VAST Admin MCP Server tool call.

Start from VAST Admin MCP Server, add the rest of your stack, and see everything your agents can call. Then put policy on all of it.

CHECK YOUR STACK →