Outbound Simulation

Outbound simulation tests agents that place calls. Tuner can’t dial into an outbound agent, so the flow is flipped: Tuner tells your system who to call, and your agent calls a simulation agent — the AI caller that plays the customer in each scenario. The “who to call” is a SIP URI rather than a phone number — sip:sim-abc123@sip.usetuner.ai instead of +15551234567. It goes in the same field your API already uses for the number, and your platform dials it like any other call.

Prerequisite: your agent must already be integrated with Tuner and sending real calls — LiveKit, Pipecat, or Custom stack. Your agent must also be set up as outbound.

How it works

You describe your call-starting API to Tuner, once. Every outbound agent has some endpoint that kicks off a call. You give Tuner that endpoint and Tuner uses it for every simulated call.
Tuner builds the scenarios. Each run generates simulation agents with a persona, an intent, and something to stress-test — the same as inbound simulation. Each gets its own SIP URI.
Tuner triggers your endpoint once per scenario, passing the SIP URI where your body expects the number, plus scenario context your agent can use.
Your agent dials and the conversation happens. From your agent’s side this is an ordinary outbound call.
You sync the call back with the SIP URI in recipient. That’s the key that matches the call to the simulation instead of treating it as production traffic.
Your production Evals run, and results appear in the Simulations table.

Configure the trigger endpoint

Open Agent Settings → Simulation Setup. This is where you describe your API to Tuner:

Agent Settings, Simulation Setup, Outbound Trigger Endpoint

Trigger URL — the endpoint on your side that places an outbound call.
Headers — whatever your endpoint needs to accept the request (an Authorization token, for example).
Body — a JSON template in your endpoint’s shape, containing Tuner’s three placeholders:

Placeholder	Replaced with
`{{sipUriToDial}}`	The SIP URI of the simulation agent. The one value your system must use — it’s who you dial.
`{{scenario.intent}}`	The intent of the call, exactly as written in Analysis Setup → Call Intents. Useful if you run different agents or logic per intent.
`{{scenario.customer_name}}`	The name of the customer being called. Useful to mimic a CRM lookup or a personalized greeting.

The key names are entirely yours (destination, to, phoneNumber, …). All three placeholders need a key in the template, but if you don’t use the intent or the name, park them under any key — only the SIP URI is essential.

Example

Say your endpoint takes a destination and dials it. Somewhere inside, there’s a line like this (LiveKit shown, same concept on any stack):

await ctx.api.sip.create_sip_participant(
    api.CreateSIPParticipantRequest(
        sip_call_to=destination,    # the phone number, or Tuner's SIP URI in simulation
        ...
    )
)

In Tuner, you mirror that endpoint with {{sipUriToDial}} in the destination field, since that’s where the number normally goes: Trigger URL

POST https://api.yourdomain.com/voice/outbound

Headers

Key	Value
`Authorization`	`Bearer YOUR_TOKEN`

Body

{
  "destination": "{{sipUriToDial}}",
  "task": "{{scenario.intent}}",
  "customerName": "{{scenario.customer_name}}"
}

The example endpoint configured in Tuner, Agent Settings → Simulation Setup

Click Save, and every simulation run will trigger your endpoint once per scenario.

Send the call back with `recipient`

When your integration syncs the finished call to Tuner, the dialed SIP URI must be in the recipient field, exactly as Tuner sent it. Whatever key you put {{sipUriToDial}} under, that’s the value to send back.

LiveKit
Pipecat
Custom stack

Python
Node.js

TunerPlugin(
    session, ctx,
    ...,                     # your existing options
    recipient=destination,   # ← the SIP URI Tuner sent, verbatim
)

new TunerPlugin(session, ctx, {
  // ...your existing options
  recipient: destination,    // ← the SIP URI Tuner sent, verbatim
});

Observer(
    ...,                     # your existing options
    recipient=destination,   # ← the SIP URI Tuner sent, verbatim
)

{
  ...,
  "recipient": destination
}

See the Create Call API for the full payload.

Want evals to use the intent or customer name? Echo them back in the call’s metadata when you sync (extra_metadata on the LiveKit plugin, or metadata in the Create Call payload). See Evaluating agents with dynamic instructions.

Managed platforms

Running your outbound agent on Vapi, Retell, or another managed platform? Step-by-step guides are coming soon.

Troubleshooting

Simulated calls show up as ordinary production calls

The synced call’s recipient didn’t match the SIP URI Tuner sent: it was never set, was modified, or a different value was sent. Compare the URI your endpoint received byte-for-byte with the recipient on the synced call.

Tuner triggers my endpoint but no call arrives

The dial failed on your side. Check your platform’s logs, and confirm your trunk can dial a SIP URI — some configurations only allow phone numbers.

My endpoint returns an error to Tuner

Check the Headers saved in Simulation Setup, and confirm the body template matches the shape your endpoint expects.

Run your first simulation

Configure your simulation mix and start a batch.

Getting Started

Integrations

Evaluation

Observability

Simulation

MCP

Guides

Resources

How it works

Configure the trigger endpoint

Example

Send the call back with `recipient`

Managed platforms

Troubleshooting

Run your first simulation

​How it works

​Configure the trigger endpoint

​Example

​Send the call back with recipient

​Managed platforms

​Troubleshooting

Run your first simulation

How it works

Configure the trigger endpoint

Example

Send the call back with `recipient`

Managed platforms

Troubleshooting