# tunable_list

List all system tunables (sysctl, loader, and rc variables).

Agent View of the PolicyLayer registry record for `tunable_list`. HTML page: https://policylayer.com/tools/spranab-truenas-mcp/tunable-list

## Facts

- Tool: `tunable_list`
- Server: Truenas (`spranab/truenas-mcp`) — https://policylayer.com/tools/spranab-truenas-mcp.md
- Homepage: https://github.com/spranab/truenas-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": "tunable_list",
    "arguments": {}
  }
}
```

## Why tunable_list is rated Low

This tool queries system tunables (sysctl, loader, and rc variables) to display their current values. It has no side effects, does not modify data, and does not execute code or commands. It is purely informational retrieval.

From the tool's own definition: "Tool name is 'tunable_list' and description states 'List all system tunables' - a read-only operation that retrieves system configuration information without modifying or executing anything."

## Use case

AI agents call tunable_list to retrieve information from Truenas 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 Truenas:

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

## Other tools on Truenas (278)

- `acme_dns_authenticator_delete` — Destructive — https://policylayer.com/tools/spranab-truenas-mcp/acme-dns-authenticator-delete.md
- `alertservice_delete` — Destructive — https://policylayer.com/tools/spranab-truenas-mcp/alertservice-delete.md
- `api_key_delete` — Destructive — https://policylayer.com/tools/spranab-truenas-mcp/api-key-delete.md
- `app_delete` — Destructive — https://policylayer.com/tools/spranab-truenas-mcp/app-delete.md
- `app_rollback` — Destructive — https://policylayer.com/tools/spranab-truenas-mcp/app-rollback.md
- `boot_attach_disk` — Destructive — https://policylayer.com/tools/spranab-truenas-mcp/boot-attach-disk.md
- `boot_detach_disk` — Destructive — https://policylayer.com/tools/spranab-truenas-mcp/boot-detach-disk.md
- `bootenv_delete` — Destructive — https://policylayer.com/tools/spranab-truenas-mcp/bootenv-delete.md
- `certificate_delete` — Destructive — https://policylayer.com/tools/spranab-truenas-mcp/certificate-delete.md
- `cloud_backup_abort` — Destructive — https://policylayer.com/tools/spranab-truenas-mcp/cloud-backup-abort.md
- `cloud_backup_delete` — Destructive — https://policylayer.com/tools/spranab-truenas-mcp/cloud-backup-delete.md
- `cloudsync_credentials_delete` — Destructive — https://policylayer.com/tools/spranab-truenas-mcp/cloudsync-credentials-delete.md
- `cloudsync_delete` — Destructive — https://policylayer.com/tools/spranab-truenas-mcp/cloudsync-delete.md
- `cronjob_delete` — Destructive — https://policylayer.com/tools/spranab-truenas-mcp/cronjob-delete.md
- `dataset_delete` — Destructive — https://policylayer.com/tools/spranab-truenas-mcp/dataset-delete.md
- `directory_services_leave` — Destructive — https://policylayer.com/tools/spranab-truenas-mcp/directory-services-leave.md
- `disk_wipe` — Destructive — https://policylayer.com/tools/spranab-truenas-mcp/disk-wipe.md
- `group_delete` — Destructive — https://policylayer.com/tools/spranab-truenas-mcp/group-delete.md
- `initshutdown_delete` — Destructive — https://policylayer.com/tools/spranab-truenas-mcp/initshutdown-delete.md
- `iscsi_extent_delete` — Destructive — https://policylayer.com/tools/spranab-truenas-mcp/iscsi-extent-delete.md
- `iscsi_initiator_delete` — Destructive — https://policylayer.com/tools/spranab-truenas-mcp/iscsi-initiator-delete.md
- `iscsi_portal_delete` — Destructive — https://policylayer.com/tools/spranab-truenas-mcp/iscsi-portal-delete.md
- `iscsi_target_delete` — Destructive — https://policylayer.com/tools/spranab-truenas-mcp/iscsi-target-delete.md
- `iscsi_targetextent_delete` — Destructive — https://policylayer.com/tools/spranab-truenas-mcp/iscsi-targetextent-delete.md
- `keychaincredential_delete` — Destructive — https://policylayer.com/tools/spranab-truenas-mcp/keychaincredential-delete.md
- `network_interface_delete` — Destructive — https://policylayer.com/tools/spranab-truenas-mcp/network-interface-delete.md
- `network_rollback_changes` — Destructive — https://policylayer.com/tools/spranab-truenas-mcp/network-rollback-changes.md
- `network_static_route_delete` — Destructive — https://policylayer.com/tools/spranab-truenas-mcp/network-static-route-delete.md
- `nfs_share_delete` — Destructive — https://policylayer.com/tools/spranab-truenas-mcp/nfs-share-delete.md
- `pool_export` — Destructive — https://policylayer.com/tools/spranab-truenas-mcp/pool-export.md
- …and 248 more: https://policylayer.com/tools/spranab-truenas-mcp.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=spranab-truenas-mcp · API: https://policylayer.com/registry/api · Policy library: https://policylayer.com/policies/spranab-truenas-mcp