> ## Documentation Index
> Fetch the complete documentation index at: https://unmute.ai/llms.txt
> Use this file to discover all available pages before exploring further.
> ## Agent Instructions
> Unmute compiles to exactly four targets. Pipecat and LiveKit are code targets: compile writes a Python project you run. SLNG is a hosted target: compile writes a deployment body and SLNG runs the agent, so it has no `unmute dev`. Twilio compiles to a small Python app that Twilio ConversationRelay calls; you host it, and it has no `unmute dev` either. Those four are the only values `provider` accepts in `targets.yaml`. Deepgram and ElevenLabs appear in these docs as model vendors, which is not the same thing as a target, and `slng` is both.
> The Go structs in `internal/spec` and `internal/ir` are the schema truth. Check a field against them, or run `unmute validate`, rather than against what you remember.
# Phone calls in code
> Take calls in, place calls out, and transfer a caller to a person, the same way on LiveKit and Pipecat.
The library reads who is calling, places outbound calls, and gives the model a tool that transfers the caller to a person. Your SIP trunk or carrier stays yours.
## Take a call in
Read the caller's number into the call's state once the call starts.
```python LiveKit theme={null}
from unmute_core.livekit import sip_call_info
participant = await ctx.wait_for_participant()
metadata = json.loads(ctx.job.metadata or "{}")
state = CallState(State, call=sip_call_info(participant, metadata))
```
```python Pipecat theme={null}
from unmute_core.pipecat import telephony_call_info
state = CallState(State, call=telephony_call_info(runner_args.call_data))
```
`state.call.calling_number` is the caller, and `state.call.called_number` is your number. On Pipecat, set the pipeline's sample rates to 8000, because a phone line carries 8 kHz audio.
## Call someone
```python LiveKit theme={null}
from unmute_core.livekit import DialError, SipLine, greet
line = SipLine(session, trunk=trunk, caller_id=os.environ["FROM_NUMBER"])
try:
answered = await line.dial(metadata["phone_number"])
except DialError:
ctx.shutdown("nobody answered")
return
if not answered.ended: # ended is True when a voicemail picked up and the call is over
greet(session, GREETING, state)
```
```xml Pipecat with Twilio theme={null}
```
On LiveKit, dispatch the job with `phone_number` in its metadata. `dial` waits until someone answers, and hangs up on a voicemail. On Pipecat, your app asks the carrier to place a call that streams to the bot. With a Daily room, call `dial_out(transport, worker, "sip:+34910000000@trunk.example")`.
## Transfer to a person
Describe where the caller goes, then give the model a tool for it. The model calls the tool with no arguments, so it never sees the number.
```python agent.py theme={null}
from unmute_core.telephony import Transfer, transfer_tool
BILLING = Transfer(
"send_to_billing",
"+34910000000",
description="Transfer the caller to billing when they ask about an invoice.",
)
tools = ToolRegistry([*my_tools, transfer_tool(BILLING, line)])
```
`line` is the call's phone line. Build one per call:
```python LiveKit theme={null}
line = SipLine(session, trunk=trunk, caller_id=os.environ["FROM_NUMBER"])
```
```python Pipecat with Twilio theme={null}
line = TwilioLine(
state.call.carrier_call_id,
account_sid=os.environ["TWILIO_ACCOUNT_SID"],
auth_token=os.environ["TWILIO_AUTH_TOKEN"],
worker=worker,
serializer=serializer, # the TwilioFrameSerializer of the transport
)
```
```python Pipecat with Telnyx theme={null}
line = TelnyxLine(
state.call.carrier_call_id,
api_key=os.environ["TELNYX_API_KEY"],
worker=worker,
serializer=serializer,
)
```
1. The tool says "Putting you through now, one moment." The caller cannot cut the transfer off.
2. On success, the call ends with the reason `transferred`.
3. When nobody answers, the model hears why and keeps helping the caller. Pass `on_unavailable="hangup"` to end the call instead.
On LiveKit Cloud, `Transfer(..., mode="warm")` calls the person first and briefs them while the caller hears hold music.
## Voicemail
```python LiveKit theme={null}
answered = await line.dial(number, on_voicemail="leave_message")
```
```python Pipecat theme={null}
from unmute_core.pipecat import voicemail_tool
tool = voicemail_tool(on_voicemail="leave_message", call=call)
flows = UnmuteFlows(..., native_tools=[tool])
```
`hangup`, the default, ends the call at once. `leave_message` has the model say a short message first.
## What each route supports
| Route | Line | Transfer | Warm transfer | Outbound call | Voicemail |
| - | - | - | - | - | - |
| LiveKit SIP, any trunk | `SipLine` | yes | yes, on LiveKit Cloud | `SipLine.dial` | `dial(on_voicemail=)` |
| Pipecat, Twilio | `TwilioLine` | yes | no | your app asks Twilio | `voicemail_tool` |
| Pipecat, Telnyx | `TelnyxLine` | yes | no | your app asks Telnyx | `voicemail_tool` |
| Pipecat, Plivo or Exotel | none | no | no | your app asks the carrier | `voicemail_tool` |
| Pipecat, Daily room over SIP | `DailySipLine` | yes | no | `dial_out` | `voicemail_tool` |
For DTMF and IVR, use the framework's own tools: `GetDtmfTask` on LiveKit, `IVRNavigator` on Pipecat.
## Where to go next
Every argument, each route in detail, and warm transfers.
Opening, greeting and ending the call.
Give the call to another agent instead of a person.
The `agent.yaml` side of transfers and escalations.
This documentation is built and hosted on [Mintlify](https://mintlify.com), a developer documentation platform.