Develop with helm dev

A studio can be built and run with no helmstudio installed, no daemon, no registry — and, where the model allows, without the checkpoint. helm dev is how, and it is not a separate imitation of helmstudio: it is the daemon's own supervisor, manifest parser and platform API, run for one studio from a local manifest.

What helm dev does

Run in the studio's checkout, it:

• reads helmstudio.yaml, or the manifest named by -f, and refuses one that does not validate;
• keeps the studio's data — its database, assets, logs and stage directories — in .helm, beside the manifest;
• serves the platform API on a free loopback port, or on -addr, and gives the studio a token for the capabilities its manifest declares;
• starts the studio's processes in dependency order, with {port}, {data} and {models.<name>} substituted, and waits on their health checks;
• prints each process's output, prefixed with its name, until Ctrl-C stops the group.

It runs no build step and downloads nothing: the checkout is yours, and so are the weights. If the last helm dev left the studio running, the next one takes it over rather than starting a second copy.

Weights you already have

Link each weight a command uses to the directory that holds it. The directory is read, never written.

helm dev -f helmstudio.yaml -link base=/Volumes/Models/tern-base

A launch whose command uses a weight that is not linked is refused, naming the weight.

A studio whose weights are selectable also needs one chosen: -select <weight>. Without it the launch is refused with the choices named, because picking one for you is what the launcher's approval screen is for.

Python

A studio that declares python runs in your environment: the active one, or the one -venv names. helm dev checks it is the Python version the manifest declares, and never creates or changes an environment — without one, it refuses and says how to make one.

uv venv --python 3.11
source .venv/bin/activate
uv pip install -e .
helm dev -f helmstudio.yaml

A studio that runs python3 without declaring python, like the quickstart's, runs whichever python3 is first on the PATH.

Go, without helm dev

A Go studio with one process can import the embedded provider and run the platform API in its own process. See providers.

What helm dev does not do yet

The design describes more than is built. These are not:

• helm studio init, which is to scaffold a studio. Copy the quickstart's example instead.
• helm dev --fixtures, which is to seed a gallery with sample media, so a page can be built before the model is downloaded.
• helm dev --fail, which is to inject quota rejections, conflicts and outages.
• helm test, the smoke harness, and helm doctor.
• helm adopt, which is to bring what a studio recorded under helm dev into helmstudio's library.