signoff-runtime-docker 0.0.2

Docker-backed sandbox Runtime for Signoff verifiers.

signoff-runtime-docker

Docker-backed sandbox Runtime for Signoff verifiers. Implements the signoff.runtime.Runtime protocol per CLAUDE.md §8.2.

Drop-in replacement for LocalRuntime when verifiers need to execute untrusted content (running tests / linters on AI-generated code is the motivating case — see signoff-code, which lands next). Each verifier invocation gets a fresh ephemeral container; the verifier's own Python logic still runs in the harness process, but every ctx.exec command routes through docker exec into the container.

from signoff_runtime_docker import DockerRuntime, DockerRuntimeConfig

runtime = DockerRuntime(DockerRuntimeConfig(verify_signatures=False))
# Pass `runtime` to `Harness(..., runtimes=[LocalRuntime(), runtime])`
# or let `Harness.from_config_path` auto-include it when
# signoff-runtime-docker is installed.

Safe by default: network=none, read-only workspace, read-only root fs, non-root UID (10001), strict capability drop, PID / memory / CPU limits, cosign signature verification on pulled images. See docs/runtimes.md and docs/deployment.md.

Install: pip install signoff-runtime-docker (pulls the docker Python SDK as a required dep). Requires a reachable Docker daemon at the usual socket / DOCKER_HOST.

cosign is optional but strongly recommended. When verify_signatures=True (the default), the runtime invokes cosign verify on every pulled image; missing cosign fails fast at prepare() time with a clear error. Set verify_signatures=False (logs a WARNING) if you're running against locally-built images in a trusted environment.