Models and defaults
Choose which model Nebula runs on — switch tiers from the composer, pin one to a thread, curate the workspace catalog, or bring your own endpoint.
You can choose which model Nebula runs on: a tier you switch from the composer, a specific model pinned to one conversation, a workspace default that covers everything else, or a model you bring yourself.
Nebula tiers
Nebula's own model comes in three tiers, and you switch between them from the composer — the control sits right next to where you type and shows the tier you're on. All three are available to everyone, in every workspace, with nothing to enable first.
Answers immediately. Flash is the starting tier and the right pick for everyday back-and-forth — quick questions, short edits, anything where you're waiting on the reply.
Thinks it through. Reach for Max on involved work that needs a plan before an answer: multi-step coding, or research that has to hold a lot of context at once.
Goes deepest on hard problems. Ultra spends the most time per reply, so it's worth saving for work that's genuinely stuck or unusually intricate.
The picker only appears when you're on a Nebula model. The same menu has an All models entry if you'd rather pin a specific model from another provider — do that and the tier picker steps out of the way, replaced by a chip naming the model you pinned. Dismiss the chip to go back to the tier you were on.
The workspace catalog
Everything beyond the three Nebula tiers is decided per workspace, in Settings → Workspace brain → Models. The page has two cards: Language models for chat and reasoning, Media models for image, video, audio, speech, and transcription.
A new workspace starts with the catalog empty, so only the Nebula tiers are selectable until somebody adds to it. That's deliberate — the vendor list is enormous, and a workspace picks the handful it actually wants rather than inheriting all of it.
| Workspace admin or owner | Everyone else | |
|---|---|---|
| Use any model in the catalog | Yes | Yes |
| Add a model to the catalog | Yes | No |
| Remove one from the catalog | Yes | No |
| Set the workspace default | Yes | No |
| See pricing and availability | Yes | Yes |
Members aren't locked out of the page — they see the same table with the controls greyed and a line explaining that a workspace admin manages the catalog and the default. Anything already in the catalog is theirs to use.
Need a model the workspace doesn't offer? Ask an owner or admin to add it — or ask Nebula in chat and it can walk you through what's already available. For anything unresolved, email support@nebula.gg.
Bringing your own
The catalog isn't limited to models Nebula ships. Add a model takes either a vendor model Nebula already knows about, or any OpenAI-compatible endpoint you control — including one running on your own machine, reached through the helper on your local device.
That's a topic of its own, with the form fields, the sharing rules, and the device-pinning behaviour: see Bring your own model.
Where your choice lands
A model you pick inside a conversation stays in that conversation. It doesn't follow you to your other threads, and it doesn't repoint your jobs, your miniapps, or your agents' background work.
Pick a model while you're in a thread and it pins there. Every later turn in that thread runs on it until you change it again. Only the person who started the thread can pin it — if you pick a model in someone else's thread, it applies to your turn and doesn't stick for everyone else.
Pick a model before you've started anything and it rides along into the next thread you open, then clears. The thread after that is back on the default.
Set in Settings → Workspace brain → Models by an owner or admin, and marked with a star in the table. It's what any conversation uses when nobody has pinned anything. Because it's shared, changing it moves every unpinned thread in the workspace, not just yours.
A thread that never had a model pinned falls back to whatever its agent is configured for, and then to the workspace default — so leaving all of this alone is a perfectly good way to use it.
Anything Nebula spawns from a thread — a job, a miniapp — keeps the model that thread was on when it was created, so scheduled work doesn't quietly change models underneath you.
Quick Send on the desktop app has its own tier picker, remembered on that device rather than shared with the workspace.
Plans: several angles at once
Depth isn't the only thing that changes with the tier. On Max and Ultra, when a request breaks into pieces that don't depend on each other — three things to research, a few angles to check, several options to compare — Nebula works them at the same time rather than one after another, then writes one answer from what comes back. It calls that a Plan.
You can watch it happen. A row of small dots appears under your message, one per step, each turning from grey to orange to green as it lands, with a running count like 3/4 beside them. Click the row to open the activity log, where every step is listed with what it found and how long it took — and any step that was waiting on an earlier one says so. Four steps run at a time, so a long plan works through in waves.
Nebula decides when a request is worth splitting up; there's no setting and nothing to turn on. Asking in plain language — "look at these three separately, then pull it together" — is a reasonable nudge, but it stays Nebula's call.
Flash doesn't split work up. It takes the same request in a single pass, so the answer arrives a little later on work that would have divided well.
/review is the one way to ask for a Plan on demand: it audits the conversation so far with several reviewers working at once, and runs on Ultra whatever tier you're on.
This isn't plan mode, which shares the word and nothing else. A Plan here is Nebula splitting one request across several workers at once, decided by Nebula, and only on Max and Ultra. Plan mode is /plan: you put a thread into read-only so Nebula proposes before it touches anything, on any tier.
The default vs a per-task choice
The workspace default is a starting point, not a hard rule. Agents can still pick a different model for a specific task when that gets a better result.
| Workspace default | Pinned to a thread | Per-task model | |
|---|---|---|---|
| Set in | Settings → Workspace brain → Models | The composer, inside the thread | Chosen automatically during a task |
| Who can change it | An owner or admin | Whoever started the thread | Nobody — Nebula decides |
| Applies to | Anything with no model pinned | That one thread, from then on | A single task or step |
| Survives a reload | Yes | Yes | No |
| Moves other people's threads | only unpinned ones | No | No |
Choosing a model
Performance vs. depth
Heavier models reason more deeply on complex work; lighter models reply faster and are great for quick back-and-forth. You don't have to optimize this yourself — start with the default and adjust only if replies feel too slow or not thorough enough. Because an agent can pick a stronger model for a hard step on its own, most people leave the default in place and let Nebula handle the rest.
Related
Use a miniapp
Every miniapp lives in its channel and shows up on the Miniapps page — open one alongside the chat or in fullscreen from the sidebar.
Bring your own model
Add your own model to Nebula — a routing alias to a vendor model, or any OpenAI-compatible endpoint, including one running on your own machine.