# list_instances

Lists Compute Engine virtual machine (VM) instances. Details for each instance include name, ID, status, machine type, creation timestamp, and attached guest accelerators. Use other tools to get more details about each instance. Requires project and zone as input.

Agent View of the PolicyLayer registry record for `list_instances`. HTML page: https://policylayer.com/tools/com-googleapis-compute-mcp/list-instances

## Facts

- Tool: `list_instances`
- Server: Mcp (`https://compute.googleapis.com/mcp`) — https://policylayer.com/tools/com-googleapis-compute-mcp.md
- Homepage: https://github.com/https://compute.googleapis.com/mcp
- Risk category: Read (Low risk)
- Registry record: grade F, identity unverified
- Server auth posture: open
- Server rate-limited: no
- Parameters: 4 (2 required)
- Recommended policy verdict: Allowed

## Parameters

| Parameter | Type | Required | Description |
| --- | --- | --- | --- |
| `zone` | string | yes | Required. The zone of the instances. |
| `project` | string | yes | Required. Project ID for this request. |
| `pageSize` | integer | no | Optional. The maximum number of instances to return. |
| `pageToken` | string | no | Optional. A page token received from a previous call to list instances. |

Parameters from the server's own tool schema.

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

```json
{
  "jsonrpc": "2.0",
  "id": 1,
  "method": "tools/call",
  "params": {
    "name": "list_instances",
    "arguments": {
      "zone": "<zone>",
      "project": "<project>"
    }
  }
}
```

## Why list_instances is rated Low

This tool queries and retrieves infrastructure information without creating, modifying, deleting, or executing any operations. It is a read-only operation with minimal security impact, as it merely enumerates existing resources and their basic properties. The blast radius is low since it only provides informational data.

From the tool's own definition: "Tool description states it 'Lists Compute Engine virtual machine (VM) instances' and returns 'name, ID, status, machine type, creation timestamp, and attached guest accelerators' — purely retrieval of metadata with no modification or execution capability."

## Use case

AI agents call list_instances to retrieve information from Mcp 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 Mcp:

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

## Other tools on Mcp (28)

- `delete_instance` — Destructive — https://policylayer.com/tools/com-googleapis-compute-mcp/delete-instance.md
- `reset_instance` — Execute — https://policylayer.com/tools/com-googleapis-compute-mcp/reset-instance.md
- `start_instance` — Execute — https://policylayer.com/tools/com-googleapis-compute-mcp/start-instance.md
- `stop_instance` — Execute — https://policylayer.com/tools/com-googleapis-compute-mcp/stop-instance.md
- `get_commitment_basic_info` — Read — https://policylayer.com/tools/com-googleapis-compute-mcp/get-commitment-basic-info.md
- `get_disk_basic_info` — Read — https://policylayer.com/tools/com-googleapis-compute-mcp/get-disk-basic-info.md
- `get_disk_performance_config` — Read — https://policylayer.com/tools/com-googleapis-compute-mcp/get-disk-performance-config.md
- `get_instance_basic_info` — Read — https://policylayer.com/tools/com-googleapis-compute-mcp/get-instance-basic-info.md
- `get_instance_group_manager_basic_info` — Read — https://policylayer.com/tools/com-googleapis-compute-mcp/get-instance-group-manager-basic-info.md
- `get_instance_template_basic_info` — Read — https://policylayer.com/tools/com-googleapis-compute-mcp/get-instance-template-basic-info.md
- `get_instance_template_properties` — Read — https://policylayer.com/tools/com-googleapis-compute-mcp/get-instance-template-properties.md
- `get_reservation_basic_info` — Read — https://policylayer.com/tools/com-googleapis-compute-mcp/get-reservation-basic-info.md
- `get_reservation_details` — Read — https://policylayer.com/tools/com-googleapis-compute-mcp/get-reservation-details.md
- `get_zone_operation` — Read — https://policylayer.com/tools/com-googleapis-compute-mcp/get-zone-operation.md
- `list_accelerator_types` — Read — https://policylayer.com/tools/com-googleapis-compute-mcp/list-accelerator-types.md
- `list_commitment_reservations` — Read — https://policylayer.com/tools/com-googleapis-compute-mcp/list-commitment-reservations.md
- `list_commitments` — Read — https://policylayer.com/tools/com-googleapis-compute-mcp/list-commitments.md
- `list_disks` — Read — https://policylayer.com/tools/com-googleapis-compute-mcp/list-disks.md
- `list_images` — Read — https://policylayer.com/tools/com-googleapis-compute-mcp/list-images.md
- `list_instance_attached_disks` — Read — https://policylayer.com/tools/com-googleapis-compute-mcp/list-instance-attached-disks.md
- `list_instance_group_managers` — Read — https://policylayer.com/tools/com-googleapis-compute-mcp/list-instance-group-managers.md
- `list_instance_templates` — Read — https://policylayer.com/tools/com-googleapis-compute-mcp/list-instance-templates.md
- `list_machine_types` — Read — https://policylayer.com/tools/com-googleapis-compute-mcp/list-machine-types.md
- `list_managed_instances` — Read — https://policylayer.com/tools/com-googleapis-compute-mcp/list-managed-instances.md
- `list_reservations` — Read — https://policylayer.com/tools/com-googleapis-compute-mcp/list-reservations.md
- `list_snapshots` — Read — https://policylayer.com/tools/com-googleapis-compute-mcp/list-snapshots.md
- `create_instance` — Write — https://policylayer.com/tools/com-googleapis-compute-mcp/create-instance.md
- `set_instance_machine_type` — Write — https://policylayer.com/tools/com-googleapis-compute-mcp/set-instance-machine-type.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=com-googleapis-compute-mcp · API: https://policylayer.com/registry/api · Policy library: https://policylayer.com/policies/com-googleapis-compute-mcp