> ## Documentation Index
> Fetch the complete documentation index at: https://www.bolna.ai/docs/llms.txt
> Use this file to discover all available pages before exploring further.
# Calling Guardrails: Control Outbound Call Timing and Rescheduling
> Restrict when your Bolna Voice AI agent makes outbound calls. Configure allowed calling hours, automatic rescheduling for off-hours calls, and bypass guardrails for urgent calls via API.
Calling guardrails let you restrict when your agent makes outbound calls. Calls outside the allowed window are automatically rescheduled.
***
## How It Works
Toggle on **Outbound call timing restrictions** in the [Call Tab](/agent-setup/call-tab). It is off by default.
Pick a start and end time (e.g., 9:00 AM to 9:00 PM).
When a call is triggered, the system checks the current time in the **recipient's local timezone** (detected from their phone number).
If the time falls inside the allowed window, the call is made immediately.
If the time falls outside the window, the call status is set to `rescheduled` and it is automatically queued for the next allowed start time.
The time window is based on the **recipient's timezone**, not yours. A 9 AM start means 9 AM where the recipient is located.
***
## Configure via API
You can also set calling guardrails through the API when creating or updating an agent. Use `call_start_hour` and `call_end_hour` in 24-hour format.
| Field | Type | Description |
| ----------------- | -------------- | ----------------------------------- |
| `call_start_hour` | integer (0-23) | Start of the allowed calling window |
| `call_end_hour` | integer (0-23) | End of the allowed calling window |
```bash theme={"system"}
curl --request POST \
--url https://api.bolna.ai/v2/agent \
--header 'Authorization: Bearer YOUR_API_TOKEN' \
--header 'Content-Type: application/json' \
--data '{
"agent_config": {
"agent_name": "Sales Agent",
"agent_welcome_message": "Hello, how can I help you?",
"calling_guardrails": {
"call_start_hour": 9,
"call_end_hour": 21
},
"tasks": [...]
},
"agent_prompts": {...}
}'
```
Hours use 24-hour format: 0 = midnight, 9 = 9 AM, 17 = 5 PM, 21 = 9 PM. `call_end_hour` must be greater than or equal to `call_start_hour`.
***
## Bypass Guardrails for Urgent Calls
Use the `bypass_call_guardrails` flag to skip time validation for a specific call. When set to `true`, the call goes through immediately regardless of the configured window.
```bash theme={"system"}
curl --request POST \
--url https://api.bolna.ai/call \
--header 'Authorization: Bearer YOUR_API_TOKEN' \
--header 'Content-Type: application/json' \
--data '{
"agent_id": "3c90c3cc-0d44-4b50-8888-8dd25736052a",
"recipient_phone_number": "+14155551234",
"bypass_call_guardrails": true,
"user_data": {...}
}'
```
Time-sensitive alerts that cannot wait
High-priority calls that need immediate delivery
Use the bypass flag responsibly. Calling outside allowed hours may violate local regulations or disturb recipients.
***
## Common Use Cases
Restrict calls to standard business hours so your agent only reaches out during the workday.
```json theme={"system"}
{
"calling_guardrails": {
"call_start_hour": 9,
"call_end_hour": 17
}
}
```
Calls triggered outside this window are automatically rescheduled to 9 AM the next day in the recipient's timezone.
Sales teams often reach prospects in the evening. Extend the window while still avoiding late-night calls.
```json theme={"system"}
{
"calling_guardrails": {
"call_start_hour": 9,
"call_end_hour": 21
}
}
```
During development, use the bypass flag to test call flows at any time without waiting for the allowed window.
```json theme={"system"}
{
"bypass_call_guardrails": true
}
```
***
## In-Call Reschedule Validation
When a recipient asks to reschedule during a call (e.g., "call me back at 10 PM"), the system validates the requested time against the allowed window before scheduling it.
**Validation priority:**
| Priority | Source | Description |
| -------- | ----------------------------- | -------------------------------------------------------------------------------- |
| 1 | **Calling guardrails config** | `call_start_hour` / `call_end_hour` always takes precedence |
| 2 | **Agent prompt** | If no guardrails are set, the LLM reads time restrictions from the system prompt |
| 3 | **Default window** | Falls back to 9 AM to 9 PM if neither is configured |
If the requested time falls outside the allowed window, the reschedule request is rejected entirely. The system does not adjust it to the nearest boundary.
Keep your agent prompt and guardrails config consistent. If the prompt says "call between 10 AM and 6 PM" but guardrails are set to 9 AM to 9 PM, the stricter guardrails config takes priority.
***
## Calling Regulations to Know
Many countries enforce strict rules on when businesses can make outbound calls. Calling guardrails help you stay compliant.
| Region | Regulation | Allowed Hours |
| ------------------ | -------------------------------------------- | ----------------------------------------------------------------------------------------------------- |
| **India** | TRAI (Telecom Regulatory Authority of India) | 9:00 AM to 9:00 PM IST. No calls on national Do Not Disturb (DND) registered numbers without consent. |
| **United States** | TCPA (Telephone Consumer Protection Act) | 8:00 AM to 9:00 PM in the recipient's local time. Prior express consent required for automated calls. |
| **European Union** | ePrivacy Directive | Varies by member state. Most restrict unsolicited calls to business hours and require prior consent. |
This is a general reference, not legal advice. Always verify the specific regulations that apply to your use case and region before making outbound calls.
***
## Next Steps
Configure telephony, noise, and call settings
Schedule calls in bulk with CSV uploads
Automatically retry unanswered calls
Full API reference for the call endpoint