CubeSandbox vs ephemora-cell
Hardware-isolated microVM sandboxes for AI agents — sub-60ms boot, <5MB overhead, E2B-compatible API, self-hosted on your own KVM nodes. — 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.
Both isolate agent code execution; cubesandbox is a hardware-isolated microVM with an E2B-style API for full workloads, Cell is a WASM capability boundary for tools and snippets.
| CubeSandbox | ephemora-cell | |
|---|---|---|
| Stars | 13k | 40 |
| Forks | 1.1k | 5 |
| Language | Rust | Python |
| License | NOASSERTION | Apache-2.0 |
| Last activity | 2 days ago | yesterday |
| Topics | agents, local | security, agents |
| Curated connections | 15 | 6 |
CubeSandbox — the curator's take
Reach for CubeSandbox the moment your agents execute model-generated code and "just run it in Docker" stops feeling safe — it gives every tool call a disposable hardware-isolated microVM with E2B's SDK ergonomics, minus the SaaS bill, plus snapshot/rollback of any sandbox state. The catch: it's real infrastructure — you need KVM-capable Linux hosts and someone willing to operate them. Prototyping a single local agent? A container or E2B's hosted tier is less machinery. It's a runtime, not a framework — you still bring LangGraph/AutoGen/whatever on top.
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.