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Agent Substrate: the core system

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README.md

# Agent Substrate

**A secure-by-default runtime for running millions of agent sandboxes on Kubernetes.**

[![License](https://img.shields.io/badge/License-Apache_2.0-blue.svg)](https://opensource.org/licenses/Apache-2.0)

[Quickstart](#quickstart-development) · [Architecture](docs/architecture.md) · [Roadmap](docs/roadmap.md) · [Contributing](CONTRIBUTING.md)

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## What is Agent Substrate?

Agent Substrate is a secure-by-default agent execution runtime engineered to run millions of sandboxes with 10x higher density than standard container runtimes. Purpose-built for the era of autonomous agents, Substrate delivers sub-500ms resume operations at over 500 suspend/resume activations per second with native zero-trust kernel and network isolation. It supports multiple sandbox technologies including microVMs and gVisor, enabling consistent lifecycle operations for all sandbox types.

At its core, Agent Substrate maps a larger set of “actors” (applications such as agents) onto a smaller set of ready “workers”, relying on the fact that agent-like applications tend to be idle most of the time to achieve heavy multiplexing.  It provides functionality to manage an actor’s lifecycle (e.g. create/destroy, suspend/resume), to assign actors to workers in real time, and to route incoming traffic to them.

Agent Substrate is intended to be a low-opinion system.  The workloads it manages don't have to be literal AI agents, but those are the best example of the kind of applications it is designed for.  It is not an SDK for building agents, but rather a system for running them at scale.

Agent Substrate leverages Kubernetes for the infrastructure provisioning and worker lifecycle management (Kubernetes Pods). It builds on top of Kubernetes features like Pods and Pod autoscaling, while Agent Substrate provides agent-specific scheduling and control to achieve lower latency. Using Kubernetes as the underlying system enables consistent infrastructure management across all workloads types that are required for end to end agentic deployments and allows holistic infrastructure optimizations for RL scenarios that span agentic, inference and training cycles.

## Star History

## Demo

[![Agent Substrate Demo](https://img.youtube.com/vi/ZEzkCFJkzjY/hq1.jpg)](https://www.youtube.com/watch?v=ZEzkCFJkzjY)

*Watch the Agent Substrate cluster multiplex ~250 stateful actors across just 8 physical pods.*

This demo highlights the core developer experience and "Agentic Infrastructure" capabilities of Substrate:

1.  **Actor Teleport:** High-performance suspend and resume of actors onto any available worker in the pool with sub-second activation.
2.  **State Persistence:** Persistent working memory (volatile RAM) and filesystem state preserved perfectly across hibernation cycles via full-state snapshots.
3.  **Agent Multiplexing:** Demonstrates 30x+ oversubscription by "juggling" a large registry of stateful actors onto a small pool of shared physical pods.

To reproduce this demo in your own cluster, please refer to the detailed walkthrough in the **[Counter Demo](demos/counter/README.md)**.

For more videos and walkthroughs, visit our YouTube channel: **[agent-substrate](https://www.youtube.com/channel/UCN9PPqlTtVxlcpbQ-NWpfZQ)**.

## Framework Agnostic & Compatibility

Agent Substrate is designed to be **framework and agent harness agnostic**. Because it manages standard OCI containers at the kernel level (via gVisor), it can host agents built on any stack.

*   **Agent Development Kit (ADK):** Support for ADK agents with session state preservation across invocations as actor state. Ideal for all types of agents and stateful tool or subagent calls.
*   **LangChain:** Ideal execution environment for LangChain agents and tool calls.
*   **Claude Code, CodeX, and Antigravity:** Support for high-density, stateful coding environments that preserve system state and filesystem state across sessions.
*   **Model Context Protocol (MCP):** Support for deploying secure, sandboxed MCP servers as Substrate Actors to provide durable tools for any model.

## Ecosystem & Examples

*   **[Agent Executor](https://github.com/google/ax):** A distributed agent runtime that demonstrates building a secure, hyper-scalable agent harness on Agent Substrate (see the [announcement blog](https://cloud.google.com/blog/products/ai-machine-learning/agent-executor-googles-distributed-agent-runtime) and [integration guide](https://github.com/google/ax#2-deploy-the-control-plane)).
*   **[kagent](https://github.com/kagent-dev/kagent):** A CNCF Sandbox project and Kubernetes-native framework for building, deploying, and managing AI agents that uses Agent Substrate to run sandboxed, stateful agent workloads (see the [announcement blog](https://kagent.dev/blog/the-future-of-kagent)).

## Status and compatibility

Agent Substrate is pre-1.0.  We are not making any guarantees about backward
compatibility at this stage, and APIs and behavior may still change
significantly.

### Supported Kubernetes Releases

Currently we aim to support the [latest stable release](https://kubernetes.io/releases/) of Kubernetes, and the previous minor release.

## Community

For announcements, technical discussions, and community support, please join
the **[ate-dev](https://groups.google.com/g/ate-dev)** Google Group.

We host a weekly community meeting every Thursday from 10:00am - 11:00am PST.
- Video call link: https://meet.google.com/uhq-cxvn-dhy
- Or dial: (US) +1 253-289-6971 PIN: 787 664 574 59#
- More phone numbers: https://tel.meet/uhq-cxvn-dhy?pin=9044088223662
- [Meeting notes](https://docs.google.com/document/d/1obSIvfcafLNniLYTQCcT2eCgxHqa2AQ3Ga7YTsju49s) for the weekly sync meeting
- [Recordings and transcripts](https://drive.google.com/corp/drive/u/0/folders/1rX1S6vPxPrR8dA1lEBuBEXkGKjHtG-mL) of all community meetings

We also have channels in the CNCF slack; [request an invite here](https://slack.cncf.io/)
if you don't have access.

- [#substrate-users](https://cloud-native.slack.com/archives/C0B6RCAJULW) to discuss using substrate.
- [#substrate-dev](https://cloud-native.slack.com/archives/C0B6M3E2J3D) to discuss developing substrate.

## Developing

Please see [CONTRIBUTING.md](CONTRIBUTING.md) for guidelines on contributing to
the project.  We welcome contributions of all kinds, but the project is VERY
young.  Our immediate focus is on building out the core system and demos, so we
may not be able to review or merge contributions that don't align with those
goals in the near term.

## Quickstart (Development)

To quickly set up the complete environment:

1. Make sure you have [Go](https://go.dev/doc/install), [`kubectl`](https://kubernetes.io/docs/tasks/tools/), and [`docker`](https://www.docker.com/) installed and configured on your dev machine. We will automatically manage other dependencies via Go, including [`kind`](https://kind.sigs.k8s.io/).
   A Linux host that will run more than about a thousand sandboxes also needs a larger kernel neighbor table (`net.ipv4.neigh.default.gc_thresh1/2/3` = 4096/16384/32768); `hack/create-kind-cluster.sh` warns when the host is at the default of 1024.

2. Run the following steps:
```shell
# create cluster and local registry (IPv4; IP_FAMILY=dual|ipv6 overrides)
hack/create-kind-cluster.sh

# install ate, PostgreSQL, rustfs
hack/install-ate-kind.sh --deploy-ate-system --credential-provider='{"name":"k8s.io"}'

# install counter demo
hack/install-ate-kind.sh --deploy-demo-counter

# install kubectl-ate
go install ./cmd/kubectl-ate

# create a counter actor in the demo's atespace (--template names the
# actor template, resolved in the actor's atespace)
kubectl ate create actor my-counter-1 -a ate-demo-counter --template counter

# port-forward the network router to bind to local port `8000`
kubectl port-forward -n ate-system svc/atenet-router 8000:80
```

> [!IMPORTANT]
> `{"name":"k8s.io"}` deploys the bundled credential provider with an empty,
> default-deny namespace policy. Before an actor can have a credential
> injected, grant its atespace the namespaces whose Secrets it may read; see
> [Enable it](docs/egress-credential-injection.md#enable-it).

3. In a **separate terminal**, send an HTTP request to increment the counter:
```shell
curl -X POST \
   -H "ate-target-actor: ate-demo-counter/my-counter-1" \
   -i http://localhost:8000/
```

### GKE Quickstart (Development)

1. Create and configure your environment file:
   ```bash
   cp hack/ate-dev-env.sh.example .ate-dev-env.sh

# Edit .ate-dev-env.sh to match your project and preferences, then source it:
   source .ate-dev-env.sh
   ```

2. Enable application-default credentials for gcloud:
   ```bash
   gcloud auth application-default login --project=${PROJECT_ID}
   ```

3. Provision the required GCP resources (GKE cluster, GCS, and IAM bindings):
   ```bash
   go run ./tools/setup-gcp bootstrap
   ```

On a fresh project this step also creates the atelet Workload Identity IAM
   grants that snapshots depend on — see
   [what `create iam` actually grants](tools/setup-gcp/README.md#what-create-iam-actually-grants)
   to audit them or apply them manually. If you bring your own cluster instead,
   note the required Kubernetes beta APIs can only be enabled **at cluster
   creation** — see the [Create Cluster warning](tools/setup-gcp/README.md#2-create-cluster).

4. Deploy the Agent Substrate system to your cluster:
   ```bash
   ./hack/install-ate.sh --deploy-ate-system --credential-provider='{"name":"k8s.io"}'
   ```

`--credential-provider` is required. `{"name":"k8s.io"}` also deploys the
   bundled Kubernetes Secrets provider, with a NetworkPolicy that admits only
   the egress gateway; `{"enabled":false}` turns egress credential injection off
   (see [docs/egress-credential-injection.md](docs/egress-credential-injection.md)).
   `ATE_CREDENTIAL_PROVIDER` in `.ate-dev-env.sh` is the same choice.

**Credential injection needs a namespace policy.** The bundled provider
   starts with an empty, default-deny one, so it resolves no Secrets until you
   grant each atespace the namespaces it may read; see
   [Enable it](docs/egress-credential-injection.md#enable-it).

5. You can then deploy the sample applications. See [demos/counter/README.md](demos/counter/README.md) or [demos/sandbox/README.md](demos/sandbox/README.md) for detailed walkthroughs.
   ```bash
   ./hack/install-ate.sh --deploy-demo-counter
   ```

#### Custom Setup and Deployment

You can run individual setup steps to create GCP resources as needed. See `go run ./tools/setup-gcp --help` for available options. For example:
```bash
go run ./tools/setup-gcp create cluster
go run ./tools/setup-gcp create bucket
```

To run the PostgreSQL store backend on Cloud SQL — with IAM database
authentication and no passwords — see [tools/setup-gcp/cloud-sql.md](tools/setup-gcp/cloud-sql.md).

Similarly, you can deploy or cleanup specific Agent Substrate components using the installation script. See `./hack/install-ate.sh --help` for all options.
```bash
# Re-deploy only ate-apiserver of the ATE system
./hack/install-ate.sh --deploy-ate-apiserver

# Delete everything (core system and all demos)
./hack/install-ate.sh --delete-all
```

#### Tearing down resources (GCP)

If you need to delete the resources created by the setup script, you can use the provided script `hack/teardown.sh`. This script will delete resources in the reverse order of creation and handles partial failures gracefully.

```bash
./hack/teardown.sh --all
```

Or run individual teardown steps as needed (see `./hack/teardown.sh` for available options).

#### Tearing down local `kind` resources

If you need to delete the local `kind` cluster and its registry (if it was created by `hack/create-kind-cluster.sh`):

```bash
./hack/delete-kind-cluster.sh
```

## Demos

We provide several sample applications demonstrating Agent Substrate's capabilities:

1. **[Counter Demo](demos/counter/README.md)**: A stateful Go HTTP server demonstrating state preservation across suspends/resumes, and on-demand actor resumption and routing via the Substrate router.
2. **[Sandbox Demo (Antigravity)](demos/sandbox/README.md)**: A secure, sandboxed execution environment (running Alpine Linux) that allows arbitrary shell execution while preserving filesystem state across sessions.
3. **[Claude Code Multiplex](demos/claude-code-multiplex/README.md)**: Demonstrates oversubscribing physical hardware by multiplexing multiple Claude Code agents onto a limited pool of workers.
4. **[Multi-Template](demos/multi-template/README.md)**: Two `ActorTemplate`s running different binaries share one `WorkerPool`, even though the templates live in different atespaces.
5. **[Request Parking](demos/parking/README.md)**: An oversubscribed pool where the router holds inbound requests until a worker frees up, instead of returning `503`.
6. **[Autoscaled WorkerPool](demos/autoscaled-workerpool/README.md)**: Scales a `WorkerPool` on its assigned-worker count with an HPA fed by prometheus-adapter.

### Documentation & Guides
* [Architecture](docs/architecture.md): How the control plane, node supervisor, and networking stack fit together.
* [API Configuration Guide](docs/api-guide.md): Detailed reference for configuring WorkerPools, ActorTemplates, Secrets, and Volumes.
* [Full CLI Documentation](cmd/kubectl-ate/README.md): Installation and usage for `kubectl-ate`.
* [Glossary](docs/glossary.md): Core terms (Actor, Atespace, ActorTemplate, WorkerPool, Worker, ate-api-server, atenet, atelet, ateom) and how they relate.
* [Integration Repositories](docs/integration-repos.md): Where integrations live, how their repositories are named, and how fixes flow back to core.
* [Observability Guide](docs/observability.md): Guide to actor logging, metrics, and distributed tracing.
* [Authentication Guide](docs/authentication.md): Configure trusted JWT providers and human credentials.
* [Egress Traffic](docs/egress-traffic.md): Which protocols an Actor may reach the outside world with and which are blocked.
* [Enabling man-in-the-middle (MITM) interception for Actor Egress policy](docs/egress-trust-bundle.md): Egress policies such as header injection depend on MITM interception of Actor traffic. This guide explains how an Actor should be configured to enable interception.
* [Request Parking](docs/request-parking.md): How the router parks requests through transient worker-pool saturation.
* [Rolling Upgrade Runbook](docs/upgrade.md): Upgrade a running substrate node by node without losing actor state.
* [Security Guide](docs/security.md): Security overview, security principles, and threat modeling.
* [Roadmap](docs/roadmap.md): Current limitations and what is planned next.
* [Benchmarking Guide](benchmarking/README.md): Locust-based load tests, monitoring stack, and the orchestrated benchmark harness.

## Tour

### Commands

* `cmd/ateapi`: The core control plane API server exposing gRPC endpoints to manage actor and worker lifecycles.
* `cmd/atelet`: A node-level DaemonSet that supervises physical worker pods, coordinates snapshotting, and manages state transfers.
* `cmd/atecontroller`: A Kubernetes controller that reconciles WorkerPool custom resources.
* `cmd/atenet`: A combined networking controller providing Envoy routing and proxy sidecars.
* `cmd/ateom-gvisor`: An interior-pod helper running inside sandboxed worker pods to execute `runsc` checkpoint and restore commands.
* `cmd/ateom-microvm`: The micro-VM peer of `ateom-gvisor`, running actors as cloud-hypervisor VMs.
* `cmd/podcertcontroller`: A "polyfill" that provides Pod Certificate signers that
  will eventually ship in upstream Kubernetes (with different names).
* `cmd/kubectl-ate`: A CLI tool for managing Agent Substrate resources. See its [README](cmd/kubectl-ate/README.md).
* `cmd/benchmarking`: Synthetic workloads used by the load tests, including `glutton`, which consumes RAM, disk, and file descriptors on demand.
* `tools/setup-gcp`: A provisioning utility to set up the necessary GCP infrastructure resources (GKE, GCS, IAM).
* `demos/`: Sample applications demonstrating Agent Substrate capabilities.

Repository info

Default branch: main
Latest version: v0.4.0
Created: 2026-05-14
Last activity: 2026-10-14
License: Apache-2.0
Open issues: 800
Watchers: 28

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