{"slug": "safe-code-execution-the-toolbox-image-and-a-sandbox-sidecar-v1-23-0-to-v1-23-1", "title": "Safe code execution: the toolbox image and a sandbox sidecar (v1.23.0 to v1.23.1)", "summary": "Loomcycle released v1.23.0–v1.23.1 with two opt-in approaches for safe code execution: a toolbox image for trusted single-tenant environments and a sandbox sidecar for untrusted multi-tenant code. The sandbox sidecar runs each session in an ephemeral container with strict security constraints, supporting pluggable runtimes and HTTP-MCP integration. The release also adds a sandbox bundle and a patch for HOME environment fallback.", "body_md": "RFC BI P1 ships two opt-in answers to the distroless-runtime-can't-run-code problem. Answer 1: the loomcycle-toolbox image is the SAME loomcycle binary on a Debian base preloaded with a dev toolchain (Python, Go, Rust, C++, Node + git, gh, curl, jq, rsync, wget, unzip, sqlite3) at the same uid 65532 and mount paths — a drop-in image swap that makes the existing Bash tool and Bashbox host-command fallback usable. Isolation is weak by design; single-tenant / trusted only. Answer 2: for untrusted / multi-tenant code, a standalone builder sidecar runs each session in a dedicated ephemeral container with --network none, --read-only rootfs, tmpfs /work, --cap-drop=ALL, no-new-privileges, non-root, cpu/mem/pids capped, and a pluggable --runtime (runc → runsc → kata). Loomcycle stays distroless and drives it over HTTP-MCP; loomcycle never runs a container engine itself. Six tools (sandbox_open, exec, write, read, close, list); one long-lived container per session for a compile-test-fix loop; constant-time bearer auth; principal-owned sessions; TTL GC plus boot orphan-sweep via a loomcycle.managed=1 label. Answer 3: the sandbox bundle. Enable with LOOMCYCLE_PRESETS=base,sandbox; registers the dev/sandbox agent + skill + mcp_servers.sandbox wiring. Additive: no wire RPCs, no schema migration; adapters bump to 1.23.0 in lockstep. v1.23.1 patch adds HOME in the fallback env for Go, Cargo, npm, pip caches.", "url": "https://wpnews.pro/news/safe-code-execution-the-toolbox-image-and-a-sandbox-sidecar-v1-23-0-to-v1-23-1", "canonical_source": "https://loomcycle.dev/blog/safe-code-execution-toolbox-and-sandbox.html", "published_at": "2026-07-17 06:34:23.299783+00:00", "updated_at": "2026-07-17 06:34:25.125037+00:00", "lang": "en", "topics": ["ai-tools", "developer-tools", "ai-infrastructure", "ai-safety"], "entities": ["Loomcycle"], "alternates": {"html": "https://wpnews.pro/news/safe-code-execution-the-toolbox-image-and-a-sandbox-sidecar-v1-23-0-to-v1-23-1", "markdown": "https://wpnews.pro/news/safe-code-execution-the-toolbox-image-and-a-sandbox-sidecar-v1-23-0-to-v1-23-1.md", "text": "https://wpnews.pro/news/safe-code-execution-the-toolbox-image-and-a-sandbox-sidecar-v1-23-0-to-v1-23-1.txt", "jsonld": "https://wpnews.pro/news/safe-code-execution-the-toolbox-image-and-a-sandbox-sidecar-v1-23-0-to-v1-23-1.jsonld"}}