Images and checkpoints

Images and checkpoints

Paperplanes keeps the immutable start environment separate from runtime state.

Implementation status

Prepared image digests and commit-built images are implemented in the private runtime path. Full OCI/Dockerfile bake execution is still a post-soak runtime task.

Template spec -> Image digest -> Sandbox -> Checkpoint/fork -> Checkpoint

Image

An image is an immutable, content-addressed start artifact:

paperplanes://images/<digest>

Images can come from:

• Image.build(spec) for template-in-code workflows.
• sandbox.commit(name) for docker-commit-style capture of a configured sandbox.

Committed images are tenant-scoped and not shareable by default because they can contain secrets, cookies, or local workspace state.

Checkpoint

A checkpoint captures runtime state from a sandbox. Use it for deterministic reset, fork fanout, and branch scoring.