# Omnia vs Sierra

> Omnia drives simulated users through your real tools inside your Kubernetes cluster, on the model you choose, promotes on live metrics and rolls back automatically. Sierra runs its simulations on its own platform.

Category: Customer service and voice. Checked against Sierra’s published material on 2026-10-22. Canonical page: https://www.altairalabs.ai/vs/sierra/

## Sierra tests agents on its own platform. Omnia tests them through your real tools, in your cluster.

Omnia runs the tests through your real tools in your own cluster, on the model you choose, and promotes a version on its live metrics. Sierra’s simulations run on Sierra’s platform, and its rollback is a manual step.

## When it matters: A customer asks to change the delivery address on an order that has already shipped.

**On Omnia:** That conversation ran a few hundred times before release, against your order system in a test environment, with simulated customers who changed their minds and pushed back. One run hit the carrier API returning a half-updated order, and the version stopped at the gate. (Omnia docs: https://promptarena.altairalabs.ai/arena/explanation/scenario-design/)

**On Sierra:** Sierra’s release testing simulates conversations against mock APIs. (source: https://sierra.ai/blog/agent-development-life-cycle)

## Tests that hit the real tools

Simulated users drive the agent through its tools, and assertions check the calls it made: that it verified the customer before changing the order, and that it didn’t issue a refund it shouldn’t have. (Omnia docs: https://promptarena.altairalabs.ai/arena/explanation/scenario-design/)

Sierra: Simulations run between agents and mock personas, against mock APIs, and can gate a release from CI. (source: https://sierra.ai/blog/simulations-the-secret-behind-every-great-agent)

## Your cluster, your models

Omnia installs into your Kubernetes cluster, so conversations and tool data stay inside your boundary. The agent uses whichever model you choose: Claude, GPT, Gemini, a model on Bedrock or Vertex, or one you host. (Omnia docs: https://omnia.altairalabs.ai/reference/core/provider/)

Sierra: A self-hosted option isn’t documented. Sierra describes its agents as built on a constellation of models it selects. (source: https://sierra.ai/product/trust-and-reliability)

## Promotion on live numbers

A new version starts on part of the traffic, and Omnia promotes it when its live metrics hold or rolls it back when they drop. Conversations in progress stay on the version they started with. *(enterprise)* (Omnia docs: https://omnia.altairalabs.ai/tutorials/progressive-rollouts/)

Sierra: Releases are immutable snapshots with instant rollback and A/B testing. Promotion or rollback on live metrics isn’t documented. (source: https://sierra.ai/blog/agent-studio-2-0)

## At a glance

| Topic | Omnia | Omnia docs | Sierra | Sierra docs | Source |
|---|---|---|---|---|---|
| Simulated users | Multi-turn, adversarial included. | https://promptarena.altairalabs.ai/arena/explanation/scenario-design/ | Mock personas. | documented | https://sierra.ai/blog/simulations-the-secret-behind-every-great-agent |
| Simulation against real tools | Yes, with assertions on what the agent did. | https://promptarena.altairalabs.ai/arena/explanation/scenario-design/ | Against mock APIs. | not documented | https://sierra.ai/blog/agent-development-life-cycle |
| Voice testing | Barge-in, overlapping speech and dead air. | https://promptarena.altairalabs.ai/arena/how-to/voice/setup-voice-testing/ | Voice Sims for noise and speaker variation. | documented | https://sierra.ai/product/agent-studio |
| Runs in your infrastructure | Your Kubernetes cluster. | https://promptarena.altairalabs.ai/arena/explanation/deploy/overview/ | Not documented. | not documented | https://sierra.ai/product/trust-and-reliability |
| Choose the model | Any provider, or your own. | https://omnia.altairalabs.ai/reference/core/provider/ | Not documented. | not documented | https://sierra.ai/product/trust-and-reliability |
| Metric-gated promotion | Promotion waits for the numbers; rollback is automatic. *(enterprise)* | https://omnia.altairalabs.ai/reference/evaluation/rolloutanalysis/ | Instant manual rollback. | partly documented | https://sierra.ai/blog/agent-studio-2-0 |
| Argument-level tool policy | A CEL rule on each call’s arguments. *(enterprise)* | https://omnia.altairalabs.ai/how-to/security/configure-tool-policies/ | Tools withheld until the customer is authenticated. | partly documented | https://sierra.ai/uk/blog/defense-in-depth-in-the-age-of-agents |
| Production failures become tests | A failed session becomes a regression scenario. *(enterprise)* | https://promptarena.altairalabs.ai/arena/how-to/scenarios/generate-from-production-sessions/ | Not documented. | not documented | https://sierra.ai/blog/agent-development-life-cycle |

## Questions

**How is Sierra priced?**

Sierra describes outcome-based pricing, where you pay when a conversation is resolved, with consumption pricing where it fits. Omnia runs on your infrastructure with no meter: free while you build, the core free in production, and an enterprise licence per environment per year from £30,000.

**Is Omnia only for customer service?**

No. It runs conversational agents, voice agents, and functions with typed input and output, on a schedule if you like.