# build_range_from_description

A execute tool on the Ludus FastMCP MCP server.

Agent View of the PolicyLayer registry record for `build_range_from_description`. HTML page: https://policylayer.com/tools/tjnull-ludus-fastmcp/build-range-from-description

## Facts

- Tool: `build_range_from_description`
- Server: Ludus FastMCP (`tjnull/ludus-fastmcp`) — https://policylayer.com/tools/tjnull-ludus-fastmcp.md
- Homepage: https://github.com/tjnull/Ludus-FastMCP
- Risk category: Execute (High 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": "build_range_from_description",
    "arguments": {}
  }
}
```

## Why build_range_from_description is rated High

Building a range from a description involves executing deployment logic that provisions cyber range environments. This falls under Execute rather than Write because it triggers complex external operations (infrastructure setup, environment provisioning) whose effects depend on the input description and are not simple data creation.

From the tool's own definition: "Tool name 'build_range_from_description' combined with server context indicating 'range lifecycle management' and 'scenario deployment' suggests the tool executes infrastructure provisioning operations."

## Use case

AI agents invoke build_range_from_description to trigger actions in Ludus FastMCP. What it does depends on the arguments the agent supplies, and its effects often reach beyond the immediate call: builds kicked off, notifications sent, workflows started.

## Recommended policy (PolicyLayer)

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

```json
{
  "version": "1",
  "default": "deny",
  "tools": {
    "build_range_from_description": {
      "limits": [
        {
          "counter": "build_range_from_description_rate",
          "window": "minute",
          "max": 10,
          "scope": "grant"
        }
      ]
    }
  }
}
```

## Other tools on Ludus FastMCP (230)

- `abort_and_remove_range` — Destructive — https://policylayer.com/tools/tjnull-ludus-fastmcp/abort-and-remove-range.md
- `abort_range_deployment` — Destructive — https://policylayer.com/tools/tjnull-ludus-fastmcp/abort-range-deployment.md
- `batch_remove_snapshots` — Destructive — https://policylayer.com/tools/tjnull-ludus-fastmcp/batch-remove-snapshots.md
- `cleanup_old_ranges` — Destructive — https://policylayer.com/tools/tjnull-ludus-fastmcp/cleanup-old-ranges.md
- `clear_range_access` — Destructive — https://policylayer.com/tools/tjnull-ludus-fastmcp/clear-range-access.md
- `delete_blueprint` — Destructive — https://policylayer.com/tools/tjnull-ludus-fastmcp/delete-blueprint.md
- `delete_group` — Destructive — https://policylayer.com/tools/tjnull-ludus-fastmcp/delete-group.md
- `delete_range` — Destructive — https://policylayer.com/tools/tjnull-ludus-fastmcp/delete-range.md
- `delete_range_by_user` — Destructive — https://policylayer.com/tools/tjnull-ludus-fastmcp/delete-range-by-user.md
- `delete_range_object` — Destructive — https://policylayer.com/tools/tjnull-ludus-fastmcp/delete-range-object.md
- `delete_ranges_by_status` — Destructive — https://policylayer.com/tools/tjnull-ludus-fastmcp/delete-ranges-by-status.md
- `delete_source` — Destructive — https://policylayer.com/tools/tjnull-ludus-fastmcp/delete-source.md
- `delete_template` — Destructive — https://policylayer.com/tools/tjnull-ludus-fastmcp/delete-template.md
- `destroy_vm` — Destructive — https://policylayer.com/tools/tjnull-ludus-fastmcp/destroy-vm.md
- `remove_ranges_from_group` — Destructive — https://policylayer.com/tools/tjnull-ludus-fastmcp/remove-ranges-from-group.md
- `remove_snapshot` — Destructive — https://policylayer.com/tools/tjnull-ludus-fastmcp/remove-snapshot.md
- `remove_user` — Destructive — https://policylayer.com/tools/tjnull-ludus-fastmcp/remove-user.md
- `remove_users_from_group` — Destructive — https://policylayer.com/tools/tjnull-ludus-fastmcp/remove-users-from-group.md
- `revoke_range_access` — Destructive — https://policylayer.com/tools/tjnull-ludus-fastmcp/revoke-range-access.md
- `revoke_range_from_user` — Destructive — https://policylayer.com/tools/tjnull-ludus-fastmcp/revoke-range-from-user.md
- `rollback_snapshot` — Destructive — https://policylayer.com/tools/tjnull-ludus-fastmcp/rollback-snapshot.md
- `abort_template_build` — Execute — https://policylayer.com/tools/tjnull-ludus-fastmcp/abort-template-build.md
- `apply_adversary_profile` — Execute — https://policylayer.com/tools/tjnull-ludus-fastmcp/apply-adversary-profile.md
- `apply_blueprint_to_range` — Execute — https://policylayer.com/tools/tjnull-ludus-fastmcp/apply-blueprint-to-range.md
- `apply_defender_profile` — Execute — https://policylayer.com/tools/tjnull-ludus-fastmcp/apply-defender-profile.md
- `batch_power_on_hosts` — Execute — https://policylayer.com/tools/tjnull-ludus-fastmcp/batch-power-on-hosts.md
- `batch_snapshot_hosts` — Execute — https://policylayer.com/tools/tjnull-ludus-fastmcp/batch-snapshot-hosts.md
- `build_container_based_template` — Execute — https://policylayer.com/tools/tjnull-ludus-fastmcp/build-container-based-template.md
- `build_range_from_scratch` — Execute — https://policylayer.com/tools/tjnull-ludus-fastmcp/build-range-from-scratch.md
- `build_range_from_skeleton` — Execute — https://policylayer.com/tools/tjnull-ludus-fastmcp/build-range-from-skeleton.md
- …and 200 more: https://policylayer.com/tools/tjnull-ludus-fastmcp.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=tjnull-ludus-fastmcp · API: https://policylayer.com/registry/api · Policy library: https://policylayer.com/policies/tjnull-ludus-fastmcp