🚀 Announcing Agent Sandbox v1.0.4!

We're excited to announce the release of Agent Sandbox v1.0.4! This release brings significant improvements across the board, including Kubernetes lifecycle event reporting for Sandboxes, streaming file download capabilities across SDKs, async sandboxd runtime support in Python, automatic sandbox expiration in TypeScript, enhanced concurrency isolation in the RL SDK, and numerous stability, security, and documentation enhancements.

Key Highlights

Core Controller & Lifecycle Management

Kubernetes Lifecycle Events (#1532): The Sandbox reconciler now emits Kubernetes Events across key lifecycle transitions, including SandboxPodCreated, SandboxPodCreateFailed, SandboxReady, SandboxSuspended, SandboxExpired (for Retain shutdown policies), PodSucceeded, and PodFailed. Events can be toggled via the new --disable-sandbox-events controller flag.
Terminal Validation for Long Service Names (#1630): Fixed an issue where Sandboxes with derived headless Service names exceeding the 63-character DNS-1035 limit caused controller hot-looping. Permanent apiserver invalidity errors are now classified as terminal, marking the resource as Ready=False with reason InvalidConfiguration without requeuing.
Router Cache Invalidation Fencing (#1398): Enhanced the sandbox-router Pod cache to track backing Pod UIDs alongside Sandbox UIDs, preventing delayed delete/NotReady events from old pods from evicting newly created replacement pods.

SDKs & Client Libraries

Streaming File Downloads (#1643): Added streaming file download support to the Go (ReadTo) and Python (read_to / AsyncFilesystem.read_to) SDKs. Callers can now stream files directly into custom writers/sinks without buffering large responses in memory.
Python Async sandboxd Runtime Support (#1438, #1697): Added full async support for sandboxd to AsyncSandboxClient, including gRPC-based process execution and REST filesystem operations over direct Pod tunnels, with hardened cleanup routines across connection failures and cancellations.
TypeScript SDK Expiration & Type Fixes (#1605, #1535): Added support for shutdownAfterSeconds in CreateSandboxOptions to automatically set controller-enforced expiration deadlines. Widened the return type of getSandboxClaimWarmpoolName() to Promise<string | undefined>.
Resilient Python Watch Streams (#1612): Improved watch stream reliability in K8sHelper and AsyncK8sHelper by catching transient HTTP disconnects (e.g. ProtocolError, ReadTimeoutError, ClientConnectionError) and reconnecting transparently while preserving tracked resource versions.
File Path & Sanitization Fixes (#1719, #1721, #1594): Preserved leading, trailing, and embedded spaces in Python SDK file paths, prevented double-decoding of literal percent escapes in the Python runtime, and fixed path sanitization when sandbox roots are accessed through symlinked directory aliases.

Reinforcement Learning SDK (`agent-sandbox-rl`)

Run Isolation & Safe Concurrency (#1737): Introduced run-scoped teardown selectors and FleetConfig.run_isolation modes ("names" and "namespace"), preventing concurrent training runs in shared namespaces from accidentally resizing, deleting, or stalling on each other's warm pools and templates. Added fail-fast handling on pool deletion and conditional resource writes.

Security & Governance

Hardened Command Governance Example (#1690): Upgraded governed_run.py to protect against command injection, shell chaining (;, &&, ||, |, &), command substitution ($(...) and backticks), GNU-style option abbreviations, and execution wrappers (sudo, env, xargs, timeout, exec).

Documentation & Tooling

Comprehensive Configuration & TLS Docs (#1653, #1689): Documented all 34 controller flags in the configuration reference, published end-to-end instructions for enabling secure TLS metrics serving on port 8443, and added HTTP/2 and HTTP/1.1 ALPN negotiation support.
Runtime API Specification (#1645): Published official runtime API reference documentation for sandboxd contracts, endpoints, and transport policies.
Developer Tooling & CI Enhancements (#1616, #1696, #1699, #1738, #1741): Enforced LF line endings repository-wide via .gitattributes, made E2E port-forward helpers race-free, prevented duplicate flake reports for closed issues, integrated cluster-free framework tests into the unit test suite, and improved GCP kOps benchmark validation timeouts.

Installation

Standard Install (Core + Extensions)

Recommended for most users and GitOps engines (Argo CD, Config Sync, kustomize):

kubectl apply -f https://github.com/kubernetes-sigs/agent-sandbox/releases/download/v1.0.4/sandbox-with-extensions.yaml

Selective Install

Install components separately:

# Core only:
kubectl apply -f https://github.com/kubernetes-sigs/agent-sandbox/releases/download/v1.0.4/sandbox.yaml

# Extensions (opt-in):
kubectl apply -f https://github.com/kubernetes-sigs/agent-sandbox/releases/download/v1.0.4/extensions.yaml

Python SDK

pip install k8s-agent-sandbox==1.0.4

Contributors

We extend our sincere thanks to all contributors to this release:
@1fanwang, @Flandern1211, @HasonoCell, @Pepper-rice, @Sean-790761, @XixianWasTaken, @aditya-shantanu, @alanhuangch, @aojea, @dependabot, @briankhoi, @dongjiang1989, @esposem, @janetkuo, @karimad, @khirotaka, @lunarwhite, @niting, @pauldotyu, @tomergee, @vincent0426, @vvoronko, @yujunz, @yuzhiquan

New Contributors

@niting made their first contribution in #1612
@Flandern1211 made their first contribution in #1438
@Sean-790761 made their first contribution in #1630
@pauldotyu made their first contribution in #1682
@1fanwang made their first contribution in #1721
@yujunz made their first contribution in #1594
@XixianWasTaken made their first contribution in #1699

Full Changelog: v1.0.3...v1.0.4

kubernetes-sigs/agent-sandbox v1.0.4 on GitHub