The Solar Mini 4 Hermes setup is simple: pick the free Upstage Solar Mini 4 model under Nous Portal in Hermes Agent. You can do it through Hermes Cloud, Hermes Desktop, Agent OS, or the hermes dashboard command, and it's free for two weeks starting 5 October 2026. The one thing you must get right is choosing the FREE variant, not the paid one.
📺 Watch: Solar Mini 4: FREE Hermes Agent Model!
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I showed all four routes on my channel. This guide walks you through each one step by step, plus what to do when you hit rate limits or can't find the model.
What Solar Mini 4 is (quick recap)
Solar Mini 4 is Upstage's compact model for high-volume agent work. Per Upstage, it's a 35B-parameter mixture-of-experts model with 3B active per token, 512K tokens of context in and up to 128K out. Upstage built it for tool calling, structured output, information extraction and repetitive agent workflows.
Upstage and Nous Research made it free inside Hermes Agent through Nous Portal for two weeks starting 5 October 2026. That's why you want to set it up now.
For the full specs, benchmarks and pricing, see my Solar Mini 4 review. This page is all about setup.
If you want to go deeper with Hermes, the AI Profit Boardroom has full Hermes and AI agent courses plus Agent OS, for $69/mo.
The one mistake to avoid with Solar Mini 4 Hermes
Before you start, here's the thing that trips people up.
When you search for Solar in the Hermes model list, you'll see more than one Solar Mini option. One is free. One is paid. They look almost the same.
Under Nous Portal, pick the FREE Solar Mini 4 variant. Not the paid one. If you pick the paid one, you're not getting the free two-week deal.
That's the whole trick. Get that right on whichever route you use and you're good.
Route 1: Hermes Cloud
This is the fastest way if you don't want to install anything.
- Go to portal.nousresearch.com/cloud.
- Create an agent.
- Open the model section.
- Scroll down until you see "Free".
- Pick Upstage Solar Mini 4.
That's it. Your cloud agent is now running on Solar Mini 4 for free.
While you're in that free list, you'll see other free models too. When I recorded, I saw Poolside Laguna XS 2.1, Inclusion AI Ling 3.1 Flash, and StepFun Step 3.7 Flash. That list changes, so what you see may be different. Keep it in mind, because those are your backups if Solar Mini 4 gets rate limited.
📺 Watch: Hermes + North Mini Code: New FREE API!
Route 2: Hermes Desktop with a new profile
If you use the desktop app, set Solar Mini 4 up in its own profile. That way you don't mess with the model your main agent already uses.
- Open Hermes Desktop.
- Create a new profile.
- Name it after the model. I name each profile after its model so I can switch between them fast.
- Refresh the model list.
- Click edit.
- Pick Solar Mini 4 from the free models.
The refresh step matters. If you skip it, the model might not show up yet.
New to the desktop app? My Hermes Desktop app guide walks you through installing it and getting around.
My test result
Once it was set up, I tested it. First thing I noticed: it replied fast.
Then I gave it a real task. I asked it to research the last seven days of AI automation news. It came back quickly with a sourced breakdown. For a free model, that's a solid result for basic agent work.
To be honest, it's not frontier level. It's not a Claude Opus 5.5 replacement. But it's fast and fine for basic agentic tasks, and it costs nothing right now. If you want to see how models stack up on real-world tasks, check out Goldie Bench.
Route 3: Agent OS
If you run Hermes through my Agent OS, this one is quick.
- Set up the Solar Mini 4 profile first (Route 2 above).
- Open Agent OS.
- Go to the Hermes section.
- Add the profile.
- Start chatting.
Now you can talk to your Solar Mini 4 agent right inside Agent OS, alongside your other agents. If you haven't set Agent OS up yet, start with my Agent OS guide. AI Profit Boardroom members get Agent OS included.
📺 Watch: Minimax M3 + Hermes Agent: Automate ANYTHING!
Route 4: The hermes dashboard command
This route uses the Hermes dashboard, which you open from the terminal.
- Open your terminal and run hermes dashboard.
- Go to Models.
- Click to set your main model.
- Type solar.
- Under Nous Portal, pick the FREE Solar Mini variant. Not the paid one.
This is the route where the free versus paid mistake is easiest to make, because the options sit right next to each other after you search. Slow down on step five.
For more on what the dashboard can do, see my hermes dashboard command guide.
Which route should you pick?
| Route | Best for | Key step |
|---|---|---|
| Hermes Cloud | No install, quickest start | portal.nousresearch.com/cloud, then Free, then Upstage Solar Mini 4 |
| Hermes Desktop | Desktop users who want a separate profile | New profile, refresh model list, pick from free models |
| Agent OS | People running several agents in one place | Hermes section, add the profile, chat |
| hermes dashboard | Terminal users | Models, set main model, type solar, pick the FREE variant |
If you're not sure, start with Hermes Cloud. It's the fewest steps.
Rate limits and fallback free models
Because Solar Mini 4 is free, lots of people are using it. That means rate limits happen.
Here's what to do:
- Model missing? Refresh the model list. It often just hasn't loaded yet.
- Hit a rate limit? Switch to another free model in the same list. When I recorded, the other free options included Poolside Laguna XS 2.1, Inclusion AI Ling 3.1 Flash and StepFun Step 3.7 Flash, but check the current list, because it changes.
- Want to switch fast? Keep a separate profile for each model, named after the model. Then swapping takes seconds.
This is why naming profiles after models is so handy. When one model is busy, you jump to the next and keep working.
The two-week window
Per Upstage and Nous Research, Solar Mini 4 is free in Hermes Agent through Nous Portal for two weeks starting 5 October 2026. After that, the free deal ends.
If you want to keep using it after the window, per Upstage you can use the Upstage Console API at $0.10 per million input tokens, $0.01 cached and $0.40 output, or reach it through OpenRouter as upstage/solar-mini4. Upstage is also running a 70% launch discount on the API through 10 October (UTC).
My advice: test it hard now while it's free. Throw your repetitive agent jobs at it. If it handles them well, you'll know whether it's worth paying for later.
Not sure which model should power which agent in your business? Book a free AI strategy session and we'll help you work it out.
What to use Solar Mini 4 for in Hermes
Per Upstage, it's built for information extraction, structured output, tool calling, document validation and repetitive agent workflows. That lines up with what I saw.
Good jobs to give it:
- Quick research and news roundups
- Pulling details out of long documents (512K tokens in gives you plenty of room)
- Formatting and cleaning up data
- Routine agent loops that run often
Jobs to keep on a bigger model: hard reasoning, complex coding, and anything where quality matters more than speed.
If you want to build agents that use the right model for each job, join the AI Profit Boardroom. You get Hermes and AI agent courses, Agent OS, and help from people building agents every day.
FAQ
How do I use Solar Mini 4 in Hermes for free?
Pick the free Upstage Solar Mini 4 model under Nous Portal in Hermes. The quickest way is Hermes Cloud: go to portal.nousresearch.com/cloud, create an agent, open the model section, scroll to "Free" and choose Upstage Solar Mini 4. You can also use Hermes Desktop, Agent OS or the hermes dashboard command. Always pick the FREE variant, not the paid one.
How long is Solar Mini 4 free?
Two weeks. Per Upstage and Nous Research, the free window in Hermes Agent through Nous Portal started on 5 October 2026 and runs for two weeks.
Why can't I see Solar Mini 4 in Hermes?
Refresh the model list first. That usually fixes it. In the dashboard, go to Models, set main model, and type solar to search. If it still won't load or you're rate limited, switch to another free model in the list for now.
Is Solar Mini 4 good enough to be my main Hermes model?
For basic agent tasks, yes. It's fast and handled my research test well. But it's not frontier level and not a Claude Opus 5.5 replacement, so keep a stronger model for hard reasoning and complex work.
Want a hand setting up your Hermes agents? Book a free AI strategy session.
