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substrate

Kubernetes runtime that sandboxes agents and suspends idle ones to snapshots

Stars
6.4k
License
Apache-2.0
Last commit
Nov 2026
Last release
Nov 2026
Language
Go
Stars, last 26 weeks+6,422
12 May 2026: 20 stars19 May 2026: 36 stars26 May 2026: 315 stars2 Jun 2026: 448 stars9 Jun 2026: 511 stars16 Jun 2026: 564 stars23 Jun 2026: 616 stars30 Jun 2026: 671 stars7 Jul 2026: 697 stars14 Jul 2026: 729 stars21 Jul 2026: 854 stars28 Jul 2026: 893 stars4 Aug 2026: 975 stars11 Aug 2026: 1,204 stars18 Aug 2026: 1,259 stars25 Aug 2026: 1,623 stars1 Sept 2026: 1,706 stars8 Sept 2026: 1,803 stars15 Sept 2026: 1,879 stars22 Sept 2026: 3,110 stars29 Sept 2026: 3,962 stars6 Oct 2026: 4,441 stars13 Oct 2026: 5,076 stars20 Oct 2026: 5,687 stars27 Oct 2026: 5,898 stars3 Nov 2026: 6,071 stars10 Nov 2026: 6,442 stars

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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