Docs / Hardware requirements & model tiers

Hardware requirements & model tiers

Remembering and plain search run on essentially any machine. Reasoning — the part that connects facts across notes and checks its own answer — runs a real local model, so it scales itself to what your computer can actually carry. You never pick a model by name; ModelBrain measures your RAM and CPU cores and picks the tier for you.

The tiers
Tier
Needs
Download
minimal
7.5 GB RAM, 4 CPU cores — a modest laptop or a VM
~1.5 GB, once
default
15 GB RAM, 8 CPU cores — a typical modern laptop or desktop
~2.5 GB, once
high
30 GB RAM, 8 CPU cores — a well-specced workstation
~2.5 GB, once
off
Below the minimal tier's requirements
nothing downloaded

RAM here means free RAM available to ModelBrain, not your machine's total installed RAM. Cores are your CPU's performance cores, not a raw thread count.

What actually changes between tiers

Only the model. Every reasoning feature — looking up more context, verifying its own citations, retrying a weak answer — runs identically on every tier; nothing is switched off to make a slower machine fit. A machine that can't run even the lightest model in time says so immediately (hardware_too_slow) instead of quietly returning a worse answer.

The off tier changes nothing about search, remembering, or recall — only the reasoning pass that connects facts across notes is unavailable.

Choosing it yourself

Auto-selection is the default and usually the right call. If you want to override it — trade answer quality for speed on a borderline machine, or force a lighter tier for a faster response — the reasoning_tier setting takes auto, minimal, default, high, or off. Run diagnostics at any time to see which tier and model are actually active on this machine right now.

Questions

How much RAM does ModelBrain need?

Plain search runs on essentially anything. Reasoning needs at least 7.5 GB of free RAM and 4 CPU cores for the lightest tier; 15 GB and 8 cores for the default tier; 30 GB and 8 cores for the top tier.

What happens on a machine that doesn't meet even the lightest tier?

Reasoning reports hardware_too_slow immediately rather than running a crippled version of itself. Plain search, remembering, and recall all still work fully.

Can I choose the tier myself instead of letting it auto-select?

Yes, via the reasoning_tier setting (auto, minimal, default, high, or off). diagnostics shows which tier and model are actually active.

Reasoning feels slow?

Common causes and fixes.

Troubleshooting →
Full tool reference

Every MCP tool's parameters, limits and error codes.

Docs →