#1010th of 14 in Sandboxes
substrate
Kubernetes runtime that sandboxes agents and suspends idle ones to snapshots
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- Stars
- 6.4k
- License
- Apache-2.0
- Last commit
- Nov 2026
- Last release
- Nov 2026
- Language
- Go
20 on 12 May 20266,442 on 10 Nov 2026
From GitHub's daily star counts.
Checked on GitHub.
Overview
Agent Substrate maps a large set of stateful actors, such as agents, onto a smaller pool of warm worker pods on Kubernetes. Idle actors are snapshotted out of memory and restored on request, with a stated resume time under 500ms. Each actor runs in a gVisor or Cloud Hypervisor sandbox with a SPIFFE identity, default-deny networking and an egress gateway that injects credentials outside the sandbox.
Who it is for: Platform engineers running many untrusted agents on Kubernetes
Strengths
- Snapshots RAM and filesystem state, so actors resume intact on any worker in the pool
- Egress gateway injects credentials, so sandboxed code never holds them
- Per-actor SPIFFE certificates and default-deny networking; plain containers are not allowed
- Runs standard OCI images; demos cover Claude Code and MCP servers
Weaknesses
- Requires a Kubernetes cluster; no standalone or single-host mode
- Several components to operate: API server, atelet, controller, networking and router
- README says the project is very young and may not merge off-roadmap contributions
- Only gVisor and Cloud Hypervisor sandboxes are supported
What it needs
- Needs Kubernetes, gVisor (runsc), Cloud Hypervisor, Envoy, Go, kubectl, docker
Quick answers
Is substrate open source?
Yes. Its code is on GitHub under the Apache-2.0 license.
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