The container

The image ghcr.io/mcp-tool-shop-org/si-jam-sessions carries the host binary and the scores in this repository. It does not carry the piano samples. Those stay a download, checked against the same SHA-256 the source pins.

The image is published when a version tag is pushed. 0.2.1 is ghcr.io/mcp-tool-shop-org/si-jam-sessions:0.2.1, and that tag also moves :0.2 and :latest.

What it can do

render, notes, notices, preview and help need no sound device. play and jam open an audio device. Playing through a Linux device is untested, in a container and outside one, and live MIDI input is Windows-only. Use the container to render and to export notes. Use a Windows build to play along.

The process starts as root only long enough to drop privileges. It then runs as uid 10001, unless you set HOST_UID and HOST_GID to your own, which is what you want when the command writes into a directory you mounted.

The working directory inside the image is the one that holds scores/. Leave it there. The host finds a score by walking up from that directory. Mount a folder for the files you want back, and pass a path inside that folder.

Render the score on the oscillator

docker pull ghcr.io/mcp-tool-shop-org/si-jam-sessions:0.2.1

docker run --rm \
  -e HOST_UID="$(id -u)" -e HOST_GID="$(id -g)" \
  -v "$PWD:/out" \
  ghcr.io/mcp-tool-shop-org/si-jam-sessions:0.2.1 \
  render /out/battle-hymn.wav --piece battle-hymn-glm-5.3 --voice osc

On Windows PowerShell, the same command is:

docker run --rm `
  -e HOST_UID=10001 `
  -v "${PWD}:/out" `
  ghcr.io/mcp-tool-shop-org/si-jam-sessions:0.2.1 `
  render /out/battle-hymn.wav --piece battle-hymn-glm-5.3 --voice osc

Without HOST_UID, the file is owned by uid 10001.

Notes the law commits

docker run --rm \
  -e HOST_UID="$(id -u)" -e HOST_GID="$(id -g)" \
  -v "$PWD:/out" \
  ghcr.io/mcp-tool-shop-org/si-jam-sessions:0.2.1 \
  notes /out/notes.json --piece battle-hymn-kimi-k3

The piano

fetch-piano uses curl, which the image includes. Give it a directory you can keep, and pass that directory as --samples when you render:

docker run --rm \
  -e HOST_UID="$(id -u)" -e HOST_GID="$(id -g)" \
  -v "$PWD/piano:/piano" \
  ghcr.io/mcp-tool-shop-org/si-jam-sessions:0.2.1 \
  fetch-piano --dir /piano

docker run --rm \
  -e HOST_UID="$(id -u)" -e HOST_GID="$(id -g)" \
  -v "$PWD:/out" -v "$PWD/piano:/piano" \
  ghcr.io/mcp-tool-shop-org/si-jam-sessions:0.2.1 \
  render /out/battle-hymn.wav --piece battle-hymn-glm-5.3 --voice piano --samples /piano

The archive is 742 MB. The image checks it before unpacking, and it refuses a path that climbs out of the directory you named.

Build the image yourself

From a clone, at the repository root:

docker build -t si-jam-sessions:local .
docker run --rm si-jam-sessions:local help

The build uses the toolchain in rust-toolchain.toml and cargo build -p host --release --locked.