---
id: SAND-WP-0014
type: workplan
title: "Owner-mediated governed bwrap execution"
domain: infotech
repo: sand-boxer
status: active
flavor: implementation
owner: codex
topic_slug: owner-mediated-execution
created: "2026-09-04"
updated: "2026-09-05"
state_hub_workstream_id: "b616d1cd-208f-5ecf-a4a0-a028396422c4"
---

# Owner-mediated governed bwrap execution

Promote intake `GLAS-IN-0002` into sand-boxer ownership. Replace the unusable
consumer-side `nsenter` hint with an owner-executed command boundary that remains
bound to the sandbox and its governed consumer identity. A refused execution
must never fall back to a host checkout or another extension.

## Define the governed execution contract

```task
id: SAND-WP-0014-T01
status: done
priority: high
state_hub_task_id: "1b4349de-7027-5f01-8deb-122772e1404d"
```

Define request/result schemas and evidence for exact actor/project/session/run
binding, ready/active lifecycle, workspace confinement, declared network
posture, value-free credential route references, bounded command duration, and
bounded output.

## Implement owner-mediated bwrap execution

```task
id: SAND-WP-0014-T02
status: done
priority: high
state_hub_task_id: "59f9af7c-7cd7-5e86-849f-5dfc7a3a06ee"
```

Add manager, extension, CLI, and authenticated HTTP surfaces. Only `ext.bwrap`
may execute in this slice. The extension launches an owner broker inside bwrap,
uses the sandbox workspace as its working directory, starts commands with a sanitized
environment, and fails closed if the recorded workspace is not the exact
owner-managed sandbox directory.

## Remove direct namespace-entry guidance

```task
id: SAND-WP-0014-T03
status: done
priority: high
state_hub_task_id: "4fc7d747-13d5-58e7-b89e-b72e845515aa"
```

Stop publishing raw consumer-side `nsenter` commands. Reachability describes
owner-mediated execution without exposing a misleading direct-attach route.

## Verify unit and local namespace behavior

```task
id: SAND-WP-0014-T04
status: done
priority: high
state_hub_task_id: "c7ada937-4430-59d7-b3a6-9f3f36e9a907"
```

Cover identity/state/TTL refusal, unsupported-extension refusal, exact workspace
validation, sanitized environment, credential route references, timeout/output
bounds, API authentication, lifecycle restoration, and teardown. Run the full
repository check and, when host user namespaces permit it, a non-secret live
bwrap command proof.

Implemented and verified 2026-09-04. `make check` passes with 119 tests. The
first live attempt proved that even the bwrap owner cannot reliably `setns`
from the host on this kernel (`IPC: Operation not permitted`), so execution was
moved to a small read-only broker launched inside the namespace and reached via
an owner-only Unix socket. `make smoke-bwrap-exec` then passed: actor `agt`,
project/session/run binding reached the command; cwd was the copied sandbox;
the host-source sentinel was absent; the command created an artifact; the net
namespace exposed only `lo` under declared `default: deny`, `egress: []`; no
credential routes or values were present; and teardown reported `destroyed`
with the workspace removed.

The authenticated HTTP smoke subsequently exposed and fixed a lifecycle defect:
`--die-with-parent` tied bwrap to the process handling `create`, so the namespace
could disappear before a later API `exec`. Owner sandboxes now persist across
requests and remain bounded by explicit destroy, TTL expiry, and stale reaping.

The consumer-contract audit also found that Glas needs to create a private task
file without writing through the host mirror or putting prompt content in argv.
Owner exec now supports bounded `stdin_text` (1,000,000 UTF-8 bytes), delivers it
only to the child process, and excludes it from results and lifecycle evidence.

## Prove one governed rein and coordinate consumers

```task
id: SAND-WP-0014-T05
status: wait
priority: high
state_hub_task_id: "c6812fd4-bb7b-5be0-8344-a122496fe5bc"
```

With Glas and rein-aharness, run one real selected rein command through the
owner API using an explicitly declared egress profile and catalog credential
route. Prove that the source checkout is absent, retain value-free evidence,
destroy the workspace, then update Glas readiness and Activity Core
`ACTIVITY-WP-0032-T05`. Do not trigger the production pilot before readiness
changes.

This task depends on a reviewed Glas profile revision and its matching
credential/egress/runtime contract. Glas selected the Claude route first in
GLAS-WP-0012; the earlier OpenRouter AppRole dependency applies only to the
separate open-weight profile and does not establish Claude authentication.

2026-09-05: SAND-WP-0015 implements pinned Python runtime mounts and private
namespace state, with a real rein CLI startup proof. Claude workload credential
routing, enforced provider egress, pinning/deploying the Claude executable,
and the real-model acceptance remain open in SAND-WP-0015-T04. No credential
value belongs in this workplan or State Hub.

## Acceptance criteria

- Execution requires the recorded actor, project, session, and run identity.
- Only a live, unexpired, ready sandbox can start a command; concurrent commands
  are refused.
- Command execution is argument-vector based, starts inside the copied sandbox
  workspace, and has no host/source-checkout fallback.
- `ext.bwrap` supplies its declared read-only runtime paths and enforces the
  profile's network namespace. Evidence reports default policy and egress list.
- Credential inputs are non-secret catalog route references only.
- Duration and captured output are bounded, lifecycle state is restored, and
  teardown remains idempotent.
- Consumer-facing reachability no longer recommends direct `nsenter`.