{{customer.number}} in dynamic variables doc (#72)

Author: nikhilro

fern/assistants/dynamic-variables.mdx

@@ -51,21 +51,26 @@ To leverage dynamic variables during phone calls, follow these steps:
 }
 ```
 
+**Note:** You will need to add the `{{variableName}}` in this format in all your prompts, whether it is the first message or anywhere else you want to use it.
+
+
 ## Default Variables
 
 By default, the following variables are automatically filled based on the current (UTC) time,
 meaning that you don't need to set them manually in `variableValues`:
 
-| Variable    | Description                 | Example              |
-| ----------- | --------------------------- | -------------------- |
-| `{{now}}`   | Current date and time (UTC) | Jan 1, 2024 12:00 PM |
-| `{{date}}`  | Current date (UTC)          | Jan 1, 2024          |
-| `{{time}}`  | Current time (UTC)          | 12:00 PM             |
-| `{{month}}` | Current month (UTC)         | January              |
-| `{{day}}`   | Current day of month (UTC)  | 1                    |
-| `{{year}}`  | Current year (UTC)          | 2024                 |
+| Variable                | Description                       | Example                   |
+| ----------------------- | --------------------------------- | ------------------------- |
+| `{{now}}`               | Current date and time (UTC)       | Jan 1, 2024 12:00 PM      |
+| `{{date}}`              | Current date (UTC)                | Jan 1, 2024               |
+| `{{time}}`              | Current time (UTC)                | 12:00 PM                  |
+| `{{month}}`             | Current month (UTC)               | January                   |
+| `{{day}}`               | Current day of month (UTC)        | 1                         |
+| `{{year}}`              | Current year (UTC)                | 2024                      |
+| `{{customer.number}}`   | Customer's phone number           | +1xxxxxxxxxx              |
+| `{{customer.X}}`        | Any other customer property       |                           |
+
 
-**Note:** You will need to add the `{{variableName}}` in this format in all your prompts, whether it is the first message or anywhere else you want to use it.
 
 ## Advanced Date and Time Usage