# Choose a model (/ai-teammates/choose-a-model)
Each AI teammate runs on one model, powered by one engine. You pick both when you hire it. Afterwards you can change the **model** — along with its provider and credential — from **Teammate Settings → Profile**, but the **engine** is set at hire and stays read-only there.
## Engines and models [#engines-and-models]
Helio supports two engines. The engine determines which models are available.
**Claude Code** runs Claude (and DeepSeek) models:
* **Claude Opus 4.8** — powerful, lower cost (the default Opus pick)
* **Claude Opus 4.7** — powerful, lower cost
* **Claude Sonnet 5** — balanced frontier model (the default Sonnet pick)
* **Claude Sonnet 4.6** — balanced
* **DeepSeek V4 Pro** — capable and cost-efficient
* **DeepSeek V4 Flash** — fast and cost-efficient
**Codex** runs OpenAI models:
* **GPT-5.6-Sol** — OpenAI flagship for complex work
* **GPT-5.6-Terra** — balances intelligence and cost
* **GPT-5.5** — OpenAI flagship
* **GPT-5.4** — balanced
## How to power it [#how-to-power-it]
A teammate is powered by one source. When you choose its model, the picker groups options by source:
| Method | What it uses |
| ------------------------ | -------------------------------------------------------------------- |
| **Helio · managed** | Helio provides access; usage counts against your plan |
| **Subscription** | Your Claude Code or ChatGPT subscription |
| **Third party API key** | Your own Anthropic, OpenAI, or DeepSeek key |
| **This machine's login** | The Claude / Codex login already on a device you run the teammate on |
Every plan — including the free tier — can run any model on **Helio quota**. Heavier models draw down your included balance faster; bring your own key or a subscription to pay the provider directly instead.
## Where it runs: cloud or local [#where-it-runs-cloud-or-local]
**How it's powered** (above) and **where it runs** are two separate choices. The hire wizard's **Computer** picker sets the second one — the actual machine that executes the teammate:
| Computer | What it means |
| ------------------------------------ | -------------------------------------------------------------------------------------------- |
| **Helio Computer** (Cloud, default) | Helio-hosted — ready to go, no local device needed |
| **Your devices** (a device of yours) | Runs on a device you own, using that device's own resources instead of Helio's cloud compute |
Picking one of **your devices** is what unlocks **This machine's login** as a power source in the table above: a cloud pod can't reach a Claude or Codex login sitting on your laptop, so that source only exists for a teammate running locally. Local execution also needs the Helio daemon running and connected on that device — if it goes offline, the picker marks it **Offline**, and a teammate assigned there can't run until it reconnects.
After hiring, this choice keeps showing up as **Runs on** on the teammate's Profile — **Helio Cloud** or **Private device** — read-only there just like the engine. See [Edit an AI teammate's settings](/ai-teammates/edit-settings#changing-the-model) for where it appears.
## How to choose [#how-to-choose]
**A lighter model** is fine when the task is simple, you're iterating fast, or you're watching cost — a weekly report or meeting-notes cleanup runs well on **DeepSeek V4 Pro**.
**A larger model** is worth it for deep reasoning, long documents or codebases, or when output quality matters most — reviewing a PR that spans multiple services, or breaking an ambiguous ask into prioritized tasks, needs a teammate that can hold more context and make finer judgment calls. That's when to reach for **Claude Opus 4.8**.
## Changing the model or credential [#changing-the-model-or-credential]
1. Click the **gear icon** in the teammate's channel header to open **Teammate Settings**
2. On the **Profile** section, pick a model from the grouped picker — each group is a source (Helio quota, a subscription, or a saved credential)
3. Save
You can change the model and the credential independently here — for example, move a teammate from Helio quota to your own key, or swap one model for another, without re-hiring.
A teammate hired with **This machine's login** is locked to that setup — its model and credential can't be changed from Profile. Hire a new teammate to switch.