arcbox vs ephemora-cell
Open-source container and VM runtime for macOS in pure Rust: drop-in Docker engine, sub-100ms agent sandboxes (`abctl claude`), full Linux VMs and throwaway macOS guests on one daemon. — versus — Capability-based WASM sandbox for MCP tools and agent-generated code: wasmtime + WASI with fuel, memory, time and I/O caps per run, sub-ms warm execution and signed (JCS/ES256) execution records.
Two answers to 'where does agent-written code run': arcbox gives a real container/VM on macOS, ephemora-cell a sub-millisecond WASM capability boundary â pick by whether the workload needs an OS.
| arcbox | ephemora-cell | |
|---|---|---|
| Stars | 5.1k | 40 |
| Forks | 173 | 5 |
| Language | Rust | Python |
| License | Apache-2.0 | Apache-2.0 |
| Last activity | 5 days ago | yesterday |
| Topics | local, agents | security, agents |
| Curated connections | 4 | 7 |
arcbox — the curator's take
The macOS answer to 'where does my agent run?': one daemon, its own VMM and VirtIO stack, and four workloads on it — Docker-compatible containers (your Compose files just work), disposable microVM sandboxes for agents and untrusted code, full Linux machines, and cloned macOS guests. OrbStack's speed, open source. `abctl claude` drops Claude Code into an isolated VM in one command, and the same sandbox primitive runs in ArcBox's cloud if you outgrow the laptop. NOT for Linux servers (this is a Mac runtime), and it's public beta — Docker parity is broad but not total; run `abctl doctor` before trusting a workflow.
ephemora-cell — the curator's take
Use Ephemora Cell when the thing you need to run is small, untrusted and frequent - an MCP tool, a plugin, a snippet the agent just wrote - and you want a receipt: every run returns status, fuel consumed, elapsed ms and the enforced policy in a canonicalized, signable record. 0.17 ms warm start beats any container or microVM by orders of magnitude. The catch is the WASM boundary: your workload has to compile to a .wasm/WASI module, so this is not 'run arbitrary Python or a Docker image'. For full-OS sandboxes (shell, packages, browsers) reach for cubesandbox, forkd, superserve or opensandbox instead; Cell sits *under* an MCP server as an execution primitive, not beside it as a platform. 40 stars, one author - solid tests (424) but treat the signing story as early.