# list_families

Get a flat list of available family types in the current Revit model

Agent View of the PolicyLayer registry record for `list_families`. HTML page: https://policylayer.com/tools/demolinator-revit-mcp-server/list-families

## Facts

- Tool: `list_families`
- Server: Revit MCP Server (`demolinator/revit-mcp-server`) — https://policylayer.com/tools/demolinator-revit-mcp-server.md
- Homepage: https://github.com/Demolinator/revit-mcp-server
- 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_families",
    "arguments": {}
  }
}
```

## Why list_families is rated Low

This tool performs a read-only operation that queries and returns available family types from the Revit model. It has no side effects, does not modify any data, and poses minimal risk if invoked by an AI agent. The blast radius is limited to information disclosure only.

From the tool's own definition: "Tool name 'list_families' and description 'Get a flat list of available family types in the current Revit model' indicate a query operation that retrieves information without modifying data."

## Use case

AI agents call list_families to retrieve information from Revit 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 Revit MCP Server:

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

## Other tools on Revit MCP Server (47)

- `delete_elements` — Destructive — https://policylayer.com/tools/demolinator-revit-mcp-server/delete-elements.md
- `execute_revit_code` — Execute — https://policylayer.com/tools/demolinator-revit-mcp-server/execute-revit-code.md
- `set_active_view` — Execute — https://policylayer.com/tools/demolinator-revit-mcp-server/set-active-view.md
- `transform_elements` — Execute — https://policylayer.com/tools/demolinator-revit-mcp-server/transform-elements.md
- `ai_element_filter` — Read — https://policylayer.com/tools/demolinator-revit-mcp-server/ai-element-filter.md
- `analyze_model_statistics` — Read — https://policylayer.com/tools/demolinator-revit-mcp-server/analyze-model-statistics.md
- `check_clashes` — Read — https://policylayer.com/tools/demolinator-revit-mcp-server/check-clashes.md
- `export_room_data` — Read — https://policylayer.com/tools/demolinator-revit-mcp-server/export-room-data.md
- `get_current_view_elements` — Read — https://policylayer.com/tools/demolinator-revit-mcp-server/get-current-view-elements.md
- `get_current_view_info` — Read — https://policylayer.com/tools/demolinator-revit-mcp-server/get-current-view-info.md
- `get_element_properties` — Read — https://policylayer.com/tools/demolinator-revit-mcp-server/get-element-properties.md
- `get_material_quantities` — Read — https://policylayer.com/tools/demolinator-revit-mcp-server/get-material-quantities.md
- `get_revit_model_info` — Read — https://policylayer.com/tools/demolinator-revit-mcp-server/get-revit-model-info.md
- `get_revit_status` — Read — https://policylayer.com/tools/demolinator-revit-mcp-server/get-revit-status.md
- `get_revit_view` — Read — https://policylayer.com/tools/demolinator-revit-mcp-server/get-revit-view.md
- `get_selected_elements` — Read — https://policylayer.com/tools/demolinator-revit-mcp-server/get-selected-elements.md
- `list_category_parameters` — Read — https://policylayer.com/tools/demolinator-revit-mcp-server/list-category-parameters.md
- `list_family_categories` — Read — https://policylayer.com/tools/demolinator-revit-mcp-server/list-family-categories.md
- `list_levels` — Read — https://policylayer.com/tools/demolinator-revit-mcp-server/list-levels.md
- `list_revit_views` — Read — https://policylayer.com/tools/demolinator-revit-mcp-server/list-revit-views.md
- `clear_colors` — Write — https://policylayer.com/tools/demolinator-revit-mcp-server/clear-colors.md
- `color_splash` — Write — https://policylayer.com/tools/demolinator-revit-mcp-server/color-splash.md
- `create_detail_line` — Write — https://policylayer.com/tools/demolinator-revit-mcp-server/create-detail-line.md
- `create_dimensions` — Write — https://policylayer.com/tools/demolinator-revit-mcp-server/create-dimensions.md
- `create_duct` — Write — https://policylayer.com/tools/demolinator-revit-mcp-server/create-duct.md
- `create_grid` — Write — https://policylayer.com/tools/demolinator-revit-mcp-server/create-grid.md
- `create_level` — Write — https://policylayer.com/tools/demolinator-revit-mcp-server/create-level.md
- `create_line_based_element` — Write — https://policylayer.com/tools/demolinator-revit-mcp-server/create-line-based-element.md
- `create_mep_system` — Write — https://policylayer.com/tools/demolinator-revit-mcp-server/create-mep-system.md
- `create_pipe` — Write — https://policylayer.com/tools/demolinator-revit-mcp-server/create-pipe.md
- …and 17 more: https://policylayer.com/tools/demolinator-revit-mcp-server.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=demolinator-revit-mcp-server · API: https://policylayer.com/registry/api · Policy library: https://policylayer.com/policies/demolinator-revit-mcp-server