## Thinking Path
> - Paperclip is the open source app people use to manage AI agents for
work
> - Sandbox providers are the seam that lets agent runs execute in
isolated environments; today the only first-party remote provider is
Daytona, a hosted third-party service
> - Self-hosters running Paperclip on their own infrastructure (often
Kubernetes already) have no first-party way to run agent sandboxes on a
cluster they control
> - That gap matters for teams with data-residency, sovereignty, or cost
constraints who cannot or will not send workloads to a hosted sandbox
service
> - This pull request adds a Kubernetes sandbox-provider plugin as a
standalone, workspace-excluded package: it implements every
SandboxProvider hook the Daytona provider does, on infrastructure the
operator owns
> - The benefit is that any Paperclip deployment with a Kubernetes
cluster gets multi-tenant, network-isolated, quota-bounded agent
sandboxes with zero new external dependencies
## Linked Issues or Issue Description
No existing issue. Following the feature template:
- **Problem:** Paperclip's remote sandbox execution requires a hosted
third-party provider. Self-hosters cannot run agent sandboxes on their
own Kubernetes clusters with a first-party provider.
- **Proposed solution:** A `@paperclipai/plugin-kubernetes`
sandbox-provider plugin with two backends: long-lived sandboxes via the
[kubernetes-sigs/agent-sandbox](https://github.com/kubernetes-sigs/agent-sandbox)
CRD (multi-command exec, adapter-install pattern) and one-shot
`batch/v1` Jobs (stable APIs only, no extra controllers).
- **Alternatives considered:** Driving kubectl from a generic shell
provider (no lifecycle/lease semantics), or requiring a hosted provider
(exactly the constraint this removes).
## What Changed
This is **stage 1 of 3** of a staged contribution (direction agreed with
maintainers): the plugin package alone. Stage 2 (server integration:
lease params, provider registration) and stage 3 (agent runtime images +
CI) are companion PRs that will be cross-linked from a comment here.
- New package `packages/plugins/sandbox-providers/kubernetes`
(workspace-excluded, like the path already carved out in
`pnpm-workspace.yaml`): src, unit + kind integration tests, operator
prerequisite manifests, README, smoke-test guide
- Implements the full SandboxProvider hook surface the Daytona provider
implements: `validateConfig`, `probe`, `acquireLease`, `resumeLease`,
`releaseLease`, `destroyLease`, `realizeWorkspace`, `execute`
- Two backends: `sandbox-cr` (default; long-lived pod via the
agent-sandbox `Sandbox` CR, supports multi-command exec) and `job`
(one-shot `batch/v1` Job; nothing beyond k8s 1.27+ required)
- Per-run adapter resolution: one environment serves mixed harnesses;
the per-run `adapterType` hint is read through a local optional type
extension, so the plugin typechecks and builds against the current
plugin SDK and simply falls back to the environment's configured default
adapter until stage 2 lands
- Exec-env wrapping: the Kubernetes exec API carries no environment, so
commands are wrapped to receive the run's env
- Fast-upload interception for workspace realization, scoped per lease
- Per-tenant isolation: derived namespace per company, RBAC,
ResourceQuota, restricted-PSS pod security (runAsNonRoot, drop ALL,
seccomp RuntimeDefault, no SA token automount)
- Network egress policy in two flavors: native `NetworkPolicy` and
`CiliumNetworkPolicy` (FQDN allowlists)
- Image allowlist with glob matching, registry override, and per-run
image override validation
- Per-run Kubernetes Secrets carrying agent credentials, ownerRef'd to
the Job or Sandbox CR for cascade GC
## Verification
- Standalone build, exactly as the README documents:
```bash
cd packages/plugins/sandbox-providers/kubernetes
pnpm install --ignore-workspace
pnpm test # 147 unit tests, 17 files, all green
pnpm typecheck # clean against the in-repo plugin SDK on master
pnpm build # dist/ emitted, manifest + worker entrypoints present
```
- A kind-cluster end-to-end integration test is included
(`RUN_K8S_INTEGRATION_TESTS=1 pnpm test
test/integration/end-to-end-run.test.ts`)
- Beyond CI: this provider has been verified in a production
multi-tenant deployment against five harnesses (opencode, pi, codex,
gemini, claude code) with real billed runs
## Risks
- **Zero behavior change for any existing deployment.** The package is
workspace-excluded; nothing in the server imports or loads it until
stage 2's integration lands. No existing code paths are touched.
- The default `sandbox-cr` backend depends on an alpha CRD
(`agents.x-k8s.io/v1alpha1`); the README flags this and the `job`
backend uses only stable APIs as a fallback.
- Risk surface is confined to deployments that explicitly install and
configure the plugin.
- The default runtime images (`ghcr.io/paperclipai/agent-runtime-*`) are
published by the stage 3 companion PR (#7934); until that lands,
deployments must point `runtimeImage` at their own images.
## Model Used
Claude Opus 4.8 (1M context), extended thinking, with tool use (Claude
Code).
## Checklist
- [x] I have included a thinking path that traces from project context
to this change
- [x] I have specified the model used (with version and capability
details)
- [x] I have checked ROADMAP.md and confirmed this PR does not duplicate
planned core work
- [x] I have searched GitHub for duplicate or related PRs and linked
them above
- [x] I have either (a) linked existing issues with `Fixes: #` / `Closes
#` / `Refs #` OR (b) described the issue in-PR following the relevant
issue template
- [x] I have run tests locally and they pass
- [x] I have added or updated tests where applicable
- [ ] If this change affects the UI, I have included before/after
screenshots (no UI changes)
- [x] I have updated relevant documentation to reflect my changes
- [x] I have considered and documented any risks above
- [ ] All Paperclip CI gates are green (pending this push)
- [ ] Greptile is 5/5 with no open P2s, recommendations, or follow-ups
- [x] I will address all Greptile and reviewer comments before
requesting merge
---------
Co-authored-by: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
Jannes Stubbemann
05ab45225a