vault_set · Secret Vault MCP Server MCP: Risk & Policy

WHAT IT DOES

What vault_set does on Secret Vault MCP Server

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

WHY IT NEEDS A POLICY

Why vault_set needs a policy

vault_set writes/stores secrets into the encrypted vault, which is a reversible data modification operation. This is Write rather than Destructive (no deletion) or Execute (no code execution). Severity is high because compromised tool use could write malicious secrets or overwrite legitimate ones, affecting system security and application behavior downstream.

From the tool's definition Tool name 'vault_set' combined with server context indicating AES-256-GCM encrypted secret storage. Sibling tools include 'vault_delete', 'vault_update_tags', 'vault_import', and 'vault_rotate', establishing this as a secret management system.

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

vault_set Rate-limited

vault_set 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": {
    "vault_set": {
      "limits": [
        {
          "counter": "vault_set_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 Secret Vault MCP Server, so you can run agents against it safely.

FAQ

Questions about vault_set

What does the vault_set tool do? +

vault_set. It is categorised as a Write tool in the Secret Vault 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 vault_set? +

Register the Secret Vault MCP Server MCP server in PolicyLayer and add a rule for vault_set: 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 Secret Vault MCP Server. Nothing to install.

What risk level is vault_set? +

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

Can I rate-limit vault_set? +

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

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

vault_set is provided by the Secret Vault MCP Server MCP server (sam-ueckert/vault-mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.