# list_variables

A read tool on the n8n MCP Server MCP server.

Agent View of the PolicyLayer registry record for `list_variables`. HTML page: https://policylayer.com/tools/andhit-r-n8n-mcp/list-variables

## Facts

- Tool: `list_variables`
- Server: n8n MCP Server (`andhit-r/n8n-mcp`) — https://policylayer.com/tools/andhit-r-n8n-mcp.md
- Homepage: https://github.com/andhit-r/n8n-mcp
- Risk category: Read (Low risk)
- Registry record: grade F, identity unverified
- Server rate-limited: no
- Parameters: 0
- Recommended policy verdict: Allowed

## Example call (MCP tools/call, JSON-RPC 2.0)

```json
{
  "jsonrpc": "2.0",
  "id": 1,
  "method": "tools/call",
  "params": {
    "name": "list_variables",
    "arguments": {}
  }
}
```

## Why list_variables is rated Low

The 'list_' prefix is a strong indicator of a read operation that queries and returns a collection of items (variables in this case). No side effects are implied. Although the description is empty, the naming convention combined with the tool's position among other n8n management tools strongly suggests this retrieves variable metadata without modification.

From the tool's own definition: "Tool name 'list_variables' with prefix 'list' indicates retrieval of existing data without modification. The sibling tools on this server show a clear pattern: 'create_*', 'delete_*', 'activate/deactivate_*' for write/destructive/execute operations, while…"

## Use case

AI agents call list_variables to retrieve information from n8n MCP Server without modifying anything. It is typically the context-gathering step in research, monitoring, and reporting workflows, before the agent takes action elsewhere.

## Recommended policy (PolicyLayer)

Verdict: **Allowed**. Enforced by the PolicyLayer MCP gateway (https://policylayer.com/mcp-gateway) before a call reaches n8n MCP Server:

```json
{
  "version": "1",
  "default": "deny",
  "tools": {
    "list_variables": {}
  }
}
```

## Other tools on n8n MCP Server (21)

- `delete_credential` — Destructive — https://policylayer.com/tools/andhit-r-n8n-mcp/delete-credential.md
- `delete_execution` — Destructive — https://policylayer.com/tools/andhit-r-n8n-mcp/delete-execution.md
- `delete_tag` — Destructive — https://policylayer.com/tools/andhit-r-n8n-mcp/delete-tag.md
- `delete_variable` — Destructive — https://policylayer.com/tools/andhit-r-n8n-mcp/delete-variable.md
- `delete_workflow` — Destructive — https://policylayer.com/tools/andhit-r-n8n-mcp/delete-workflow.md
- `activate_workflow` — Execute — https://policylayer.com/tools/andhit-r-n8n-mcp/activate-workflow.md
- `deactivate_workflow` — Read — https://policylayer.com/tools/andhit-r-n8n-mcp/deactivate-workflow.md
- `get_audit_log` — Read — https://policylayer.com/tools/andhit-r-n8n-mcp/get-audit-log.md
- `get_credential` — Read — https://policylayer.com/tools/andhit-r-n8n-mcp/get-credential.md
- `get_execution` — Read — https://policylayer.com/tools/andhit-r-n8n-mcp/get-execution.md
- `get_workflow` — Read — https://policylayer.com/tools/andhit-r-n8n-mcp/get-workflow.md
- `list_credentials` — Read — https://policylayer.com/tools/andhit-r-n8n-mcp/list-credentials.md
- `list_executions` — Read — https://policylayer.com/tools/andhit-r-n8n-mcp/list-executions.md
- `list_tags` — Read — https://policylayer.com/tools/andhit-r-n8n-mcp/list-tags.md
- `list_workflows` — Read — https://policylayer.com/tools/andhit-r-n8n-mcp/list-workflows.md
- `create_credential` — Write — https://policylayer.com/tools/andhit-r-n8n-mcp/create-credential.md
- `create_tag` — Write — https://policylayer.com/tools/andhit-r-n8n-mcp/create-tag.md
- `create_variable` — Write — https://policylayer.com/tools/andhit-r-n8n-mcp/create-variable.md
- `create_workflow` — Write — https://policylayer.com/tools/andhit-r-n8n-mcp/create-workflow.md
- `update_tag` — Write — https://policylayer.com/tools/andhit-r-n8n-mcp/update-tag.md
- `update_workflow` — Write — https://policylayer.com/tools/andhit-r-n8n-mcp/update-workflow.md

## For agents

This record is a snapshot. Live verdicts and the full registry:

- Check every server in your MCP config at once: `npx -y policylayer stack`
- Vet a server before you add it: install the mcp-precheck skill — `npx skills add https://policylayer.com` (skill text: https://policylayer.com/skill.md)
- Query the registry over MCP: endpoint `https://api.policylayer.com/mcp` — tools `check_mcp_server`, `check_mcp_stack`, `check_tool`, `search_registry`, `get_change_events`

---

Source: the PolicyLayer MCP registry — one continuously verified record per MCP server. Full record: https://policylayer.com/registry?q=andhit-r-n8n-mcp · API: https://policylayer.com/registry/api · Policy library: https://policylayer.com/policies/andhit-r-n8n-mcp