Agent Sandbox is a Kubernetes extension for managing isolated, stateful workloads that run as single long-lived containers with stable identities and persistent storage. It is intended for AI agent runtimes, reinforcement-learning workloads, and other applications that do not fit ordinary stateless deployments. Its catalogue skills and instructions support operating these sandbox workloads.
Borrowing it
Nothing to install: this file belongs to kubernetes-sigs/agent-sandbox. Take a copy, put it at the same path in your own repository, and replace the rules that are about this project with yours.
curl -O https://raw.githubusercontent.com/kubernetes-sigs/agent-sandbox/main/AGENTS.mdgit clone --depth 1 https://github.com/kubernetes-sigs/agent-sandboxWrote this? Show the measurements
A badge with what this costs and how it scanned, read live from this page, so it follows the numbers instead of freezing them. Markdown for a README, HTML for a documentation site or a project page.
[](https://agentmods.dev/instructions/kubernetes-sigs/agent-sandbox/agents-md)<a href="https://agentmods.dev/instructions/kubernetes-sigs/agent-sandbox/agents-md"><img src="https://agentmods.dev/badge/instructions/kubernetes-sigs/agent-sandbox/agents-md/github.svg" alt="Measured on agentmods" height="20"></a>Or the 80×15 button, for a site that already has a row of RSS and ATOM ones. Only the verdict fits; the numbers stay here.
<a href="https://agentmods.dev/instructions/kubernetes-sigs/agent-sandbox/agents-md"><img src="https://agentmods.dev/badge/instructions/kubernetes-sigs/agent-sandbox/agents-md.svg" alt="Reviewed on agentmods" width="80" height="20"></a>What it costs to keep this loaded
Counted locally with the o200k_base tokenizer, which is exact for GPT models; Claude uses its own tokenizer and its counts differ. Treat this as one consistent yardstick across the catalogue rather than a bill. Prices are per million input tokens.
| Model | Per session | Once invoked |
|---|---|---|
| Fable 5.1 | $0.05325 | $0.05325 |
| Opus 5.5 | $0.02130 | $0.02130 |
| Sonnet 5.5 | $0.01065 | $0.01065 |
| Haiku 4.5 | $0.00532 | $0.00532 |
Grade A, and why
agent-sandbox AGENTS.md scanned grade A with 0 findings against 26 rules in 11 categories — prompt injection, anti-refusal, data exfiltration, privilege escalation, supply chain, agent snooping, system-prompt leakage, SSRF and excessive agency — measured 5d ago.
A static scan of the body, not an audit. Every finding is printed with the line that produced it so you can judge whether it matters here. A mod is markdown that instructs an agent; that is exactly why what it instructs is worth reading.
Nothing flagged
None of the 26 patterns this scan looks for appear in this file: no shell pipes, no recursive deletes, no credential paths, no hidden text, no instruction-override or anti-refusal phrasing, no agent-config snooping. That is not a guarantee, it is the absence of the things that are checkable.
How it starts
The opening of the file, as written. The whole thing — 167 lines — stays where its author put it; the contents beside it link to each section on GitHub.
AGENTS.md
Guidance for AI coding agents working in this repository. Human contributors should also read CONTRIBUTING.md, docs/development.md, and docs/testing.md, which are the source of truth.
Project summary
agent-sandbox is a Kubernetes controller that provides the Sandbox CRD: a stateful, singleton, pod-backed workload with a stable identity, intended for AI agent runtimes, dev environments, notebooks, and similar use cases. It is a SIG Apps subproject (sigs.k8s.io/agent-sandbox) and follows Kubernetes / controller-runtime conventions.
- API group
agents.x-k8s.io/v1beta1:Sandbox(core). - API group
extensions.agents.x-k8s.io/v1beta1:SandboxClaim,SandboxTemplate,SandboxWarmPool(opt-in extensions). - Go module:
sigs.k8s.io/agent-sandbox(Go 1.26.x, see go.mod).
Repository layout
| Path | What lives there |
|---|---|
| .agents/skills/ | Specialized instructions for you (AI agents). See "Agent Skills" section below. |
| api/v1beta1/ | Core Sandbox types and kubebuilder markers. |
| extensions/api/v1beta1/ | SandboxClaim, SandboxTemplate, SandboxWarmPool types. |
| controllers/ | Core Sandbox reconciler + tests. |
| extensions/controllers/ | Reconcilers for the extension CRDs. |
| cmd/agent-sandbox-controller/, cmd/metrics-docs-gen/ | Controller manager entrypoint (bin/manager) and metrics reference generator. |
| internal/ | Shared internals (lifecycle, metrics, metricsdocs, rawpatch, tlsutil, utils, version). Not importable by external consumers. |
| sandbox-router/ | Go reverse-proxy router (bin/sandbox-router) for HTTP/gRPC routing, authz, and TLS to sandboxes. |
| packages/sandboxd/ | Go in-sandbox daemon (bin/sandboxd) providing gRPC process execution, filesystem, and health APIs inside sandbox pods. |
| k8s/ | Generated CRDs (k8s/crds/), RBAC (*.generated.yaml), and controller manifests. |
| helm/, olm/ | Helm chart (helm/crds/, helm/templates/) and OLM bundle/config. Generated CRDs and RBAC are synced here by make fix-go-generate. |
| clients/k8s/ | Generated Kubernetes-style clientset, listers, informers (output of dev/tools/client-gen-go.sh). Do not hand-edit. |
| clients/go/ | Hand-written high-level Go SDK that wraps the SandboxClaim lifecycle and exposes Gateway / port-forward / direct connectivity. Editable. |
| clients/python/agentic-sandbox-client/ | Hand-written Python SDK. Directory is named agentic-sandbox-client but the package publishes to PyPI as k8s-agent-sandbox — that's the name to import in docs and examples. |
| clients/typescript/agentic-sandbox-client/ | Hand-written TypeScript SDK (Node >= 22, ESM, vitest, Biome). |
| clients/integrations/ | Ecosystem adapters (mcp-server, deepagents, gymnasium, nemo-gym, openhands). |
| examples/ | Runnable sample manifests and demo apps. |
| test/e2e/, test/benchmarks/ | End-to-end and benchmark suites (Go-driven; some scenarios shell out via the Python SDK). |
| dev/tools/ | Repo tooling (lint, generate, deploy-kind, release scripts). Most make targets shell out here. |
| dev/ci/ | Prow presubmit/periodic scripts. |
| docs/ | Development, testing, configuration docs, generated reference docs, and KEPs (docs/keps/). |
| site/ | Hugo + Docsy source for https://agent-sandbox.sigs.k8s.io. Many pages are thin wrappers that include-file from the repo via mounts in site/hugo.yaml — see "Docs site mounts" below. Native page sources (lifecycle, snapshots, use-cases, runtime-templates, getting started, etc.) live only here. |
What this file has done since we first saw it
Hashed on every crawl. A supply-chain change to an agent config is a question of when, not whether, so the history is kept rather than the latest state alone.
- 5d ago Changed 73ee1e6e35d4
- 6d ago Changed · +1 lines · +36 tokens per session bdf1f66f4e22
- 17d ago Changed · +31 tokens per session 1be0e55fad9a
- 1mo ago Changed · +23 lines · +934 tokens per session a87b8371abb6
- 1mo ago Changed · -3 tokens per session 6853a8795225
- 1mo ago Changed · +1 lines · +109 tokens per session 2e5cf471e8b7
- 1mo ago First seen · 142 lines · 4,218 tokens per session scan A 55364c5c4b8f
agent-sandbox AGENTS.md is an instructions file published in the GitHub repository kubernetes-sigs/agent-sandbox (4,346 stars, last pushed today), licensed Apache-2.0. It adds 5,325 tokens to every session, about $0.0213 per session on Opus 5.5. A static security scan graded it A with 0 findings. No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-30.
Other instructions, from other repositories
vscode buildNext.instructions.md
Working notes and architecture documentation for the new esbuild-based build system in build/next. Use when making changes to the new build pipeline (transpile/bundle commands, NLS plugin, source-map handling, resource copying, or self-hosting watch tasks).
next.js AGENTS.md
AGENTS.md instructions for vercel/next.js, covering next.js development guide, codebase structure, monorepo overview, core package: packages/next and other important packages.
vscode oss-third-party-notices.instructions.md
Instructions for microsoft/vscode, covering vs code oss third-party-notices pipeline, architecture, pipeline flow in ci, cache eligibility and rollout and applying the notice (cutover).
langchain AGENTS.md
AGENTS.md instructions for langchain-ai/langchain, covering global development guidelines for the langchain monorepo, corridor security analysis, project architecture and context, monorepo structure and development tools & commands.
vscode copilot-instructions.md
Copilot instructions for microsoft/vscode, covering vs code copilot instructions, project overview, root folders, core architecture (src/ folder) and built-in extensions (extensions/ folder).
deno copilot-instructions.md
Copilot instructions for denoland/deno, covering deno development guide for github copilot, network access, high level overview, key directories and key files to understand first.