1# Redirection Rules 2 3 4Generally, UI redirection within an application is triggered by users. However, an application can call **startAbility()** to implement UI redirection. 5 6 7The PageAbility has a UI. It can use **startAbility()** to start an ability that has a UI and is visible to users. 8 9 10The **exported** field under **abilities** in the **config.json** file specifies whether an ability can be started by other application components. 11 12 13**Table 1** Description of exported 14 15| Name| Description| Initial Value Allowed| 16| -------- | -------- | -------- | 17| exported | Whether the ability can be called by other applications.<br>**true**: The ability can be called by any application.<br>**false**: The ability can be called only by other components of the same application.| Yes (initial value: **false**)| 18 19 20To enable an ability to be called by any application, configure the **config.json** file as follows: 21 22```ts 23{ 24 "module": { 25 // ... 26 "abilities": [ 27 { 28 "exported": "true", 29 // ... 30 } 31 ] 32 } 33} 34``` 35 36 37If the ability contains **skills**, you are advised to set **exported** to **true** so that the ability can be [implicitly started](explicit-implicit-want-mappings.md#matching-rules-of-implicit-want) by other applications. If this attribute is set to **false**, the system returns **PERMISSION_DENIED** when other applications attempt to start the ability. In this case, a system application can request the [START_INVISIBLE_ABILITY](../security/permission-list.md) permission to start the ability. Example abilities with **exported** set to **false** are home screen, voice assistant, or search assistant. 38