# set_group

A write tool on the Ha Nexus Agent MCP server.

Agent View of the PolicyLayer registry record for `set_group`. HTML page: https://policylayer.com/tools/fistacho-ha-nexus-agent/set-group

## Facts

- Tool: `set_group`
- Server: Ha Nexus Agent (`fistacho/ha-nexus-agent`) — https://policylayer.com/tools/fistacho-ha-nexus-agent.md
- Homepage: https://github.com/Fistacho/ha-nexus-agent
- Risk category: Write (Medium risk)
- Registry record: grade F, identity unverified
- Server rate-limited: no
- Parameters: 0
- Recommended policy verdict: Rate-limited

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

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

## Why set_group is rated Medium

The tool appears to create or modify group configurations in Home Assistant. This is a Write operation (creates/modifies data reversibly) rather than Execute or Destructive, since groups can be reconfigured or deleted. Severity is high because misconfiguration of groups could affect automation rules or entity organization across the smart home.

From the tool's own definition: "Tool name is 'set_group' with empty description. In Home Assistant context, groups are configuration entities that logically aggregate devices/entities. Setting a group creates or modifies this aggregation, reversible through further edits or deletion."

## Use case

AI agents use set_group to create or update resources in Ha Nexus Agent, usually the action step of a workflow, after the agent has gathered context. Every call changes real data in your Ha Nexus Agent environment.

## Recommended policy (PolicyLayer)

Verdict: **Rate-limited**. Enforced by the PolicyLayer MCP gateway (https://policylayer.com/mcp-gateway) before a call reaches Ha Nexus Agent:

```json
{
  "version": "1",
  "default": "deny",
  "tools": {
    "set_group": {
      "limits": [
        {
          "counter": "set_group_rate",
          "window": "minute",
          "max": 30,
          "scope": "grant"
        }
      ]
    }
  }
}
```

## Other tools on Ha Nexus Agent (308)

- `abort_config_flow` — Destructive — https://policylayer.com/tools/fistacho-ha-nexus-agent/abort-config-flow.md
- `abort_options_flow` — Destructive — https://policylayer.com/tools/fistacho-ha-nexus-agent/abort-options-flow.md
- `clean_mqtt` — Destructive — https://policylayer.com/tools/fistacho-ha-nexus-agent/clean-mqtt.md
- `delete_area` — Destructive — https://policylayer.com/tools/fistacho-ha-nexus-agent/delete-area.md
- `delete_automation` — Destructive — https://policylayer.com/tools/fistacho-ha-nexus-agent/delete-automation.md
- `delete_backup` — Destructive — https://policylayer.com/tools/fistacho-ha-nexus-agent/delete-backup.md
- `delete_blueprint` — Destructive — https://policylayer.com/tools/fistacho-ha-nexus-agent/delete-blueprint.md
- `delete_card` — Destructive — https://policylayer.com/tools/fistacho-ha-nexus-agent/delete-card.md
- `delete_category` — Destructive — https://policylayer.com/tools/fistacho-ha-nexus-agent/delete-category.md
- `delete_config_file` — Destructive — https://policylayer.com/tools/fistacho-ha-nexus-agent/delete-config-file.md
- `delete_css_custom_property` — Destructive — https://policylayer.com/tools/fistacho-ha-nexus-agent/delete-css-custom-property.md
- `delete_event` — Destructive — https://policylayer.com/tools/fistacho-ha-nexus-agent/delete-event.md
- `delete_label` — Destructive — https://policylayer.com/tools/fistacho-ha-nexus-agent/delete-label.md
- `delete_media` — Destructive — https://policylayer.com/tools/fistacho-ha-nexus-agent/delete-media.md
- `delete_pipeline` — Destructive — https://policylayer.com/tools/fistacho-ha-nexus-agent/delete-pipeline.md
- `delete_scene` — Destructive — https://policylayer.com/tools/fistacho-ha-nexus-agent/delete-scene.md
- `delete_script` — Destructive — https://policylayer.com/tools/fistacho-ha-nexus-agent/delete-script.md
- `delete_style_preset` — Destructive — https://policylayer.com/tools/fistacho-ha-nexus-agent/delete-style-preset.md
- `delete_theme` — Destructive — https://policylayer.com/tools/fistacho-ha-nexus-agent/delete-theme.md
- `delete_zone` — Destructive — https://policylayer.com/tools/fistacho-ha-nexus-agent/delete-zone.md
- `git_rollback_file` — Destructive — https://policylayer.com/tools/fistacho-ha-nexus-agent/git-rollback-file.md
- `git_rollback_to_commit` — Destructive — https://policylayer.com/tools/fistacho-ha-nexus-agent/git-rollback-to-commit.md
- `lvgl_delete_widget` — Destructive — https://policylayer.com/tools/fistacho-ha-nexus-agent/lvgl-delete-widget.md
- `notify_persistent_dismiss` — Destructive — https://policylayer.com/tools/fistacho-ha-nexus-agent/notify-persistent-dismiss.md
- `notify_persistent_dismiss_all` — Destructive — https://policylayer.com/tools/fistacho-ha-nexus-agent/notify-persistent-dismiss-all.md
- `remove_dashboard_resource` — Destructive — https://policylayer.com/tools/fistacho-ha-nexus-agent/remove-dashboard-resource.md
- `remove_device` — Destructive — https://policylayer.com/tools/fistacho-ha-nexus-agent/remove-device.md
- `remove_energy_source` — Destructive — https://policylayer.com/tools/fistacho-ha-nexus-agent/remove-energy-source.md
- `remove_group` — Destructive — https://policylayer.com/tools/fistacho-ha-nexus-agent/remove-group.md
- `remove_integration` — Destructive — https://policylayer.com/tools/fistacho-ha-nexus-agent/remove-integration.md
- …and 278 more: https://policylayer.com/tools/fistacho-ha-nexus-agent.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=fistacho-ha-nexus-agent · API: https://policylayer.com/registry/api · Policy library: https://policylayer.com/policies/fistacho-ha-nexus-agent