---
title: xs:boolean - X4 schema type
summary: xs:boolean: An XML Schema boolean with literals true, false, 1 and 0. Lua rules for numeric zero do not apply.
section: reference
kind: guide
status: reference
updated: 2026-10-27
tags: ["XSD","schema","types"]
sources: ["https://wiki.egosoft.com/X4%20Foundations%20Wiki/Modding%20Support/","https://www.w3.org/TR/xmlschema11-2/"]
---
## Meaning

xs:boolean: An XML Schema boolean with literals true, false, 1 and 0. Lua rules for numeric zero do not apply.

An XSD type constrains XML, rather than declaring a Lua return or the payload type of event.param. A valid schema value does not prove a successful game effect.

## Schema structure

`W3C XML Schema`

| Property | Value |
| --- | --- |
| Construction | `builtin` |

restriction narrows a base type; union accepts one of its branches; list describes whitespace-separated items. Enumeration values in one restriction are alternatives. Pattern syntax is XML Schema regex, not Lua patterns or JavaScript RegExp. Constraints inherited from the base type still apply.

## Example and result

```text
false
```

**What happens:** The literal false denotes a false value.

Object and group variables must already exist in the correct MD / AI context. These are learning fragments, not a complete runnable mission.

## Used by

| Element | Attribute | Schema |
| --- | --- | --- |
| [`loadout`](wiki:api-md-loadout-611d5840) | `debug` | `libraries/gamestarts.xsd` |
| [`owner`](wiki:api-md-owner-85a24084) | `negate` | `libraries/unlocks.xsd` |
| [`position`](wiki:api-md-position-e04350c5) | `safepos` | `libraries/libraries.xsd` |
| [`speak`](wiki:api-md-speak-8298e787) | `nosubtitles` | `libraries/voicesequences.xsd` |


[All schema types](wiki:schema-types) · [Lua / MD value types](wiki:types)