E2B implementation of the @deepseek-ai/dsh-subprocess seam. It has no config: load @deepseek-ai/dsh-e2b first, then this service in place of dsh-subprocess-local. Existing Bash, PTY, LSP, and subprocess Code Runtime consumers then execute in the shared remote sandbox without E2B-specific capability packages.

Behavior

Asynchronous remote start — the synchronous seam returns a handle immediately while Sandbox.commands.run(..., { background: true }) starts remotely. pid is -1 until the wrapper publishes and the adapter validates its process-group id; stdin and ordinary observation wait for that publication, while cancellation can stop the provisional SDK handle first.
Execution-world coordinates — cwd and private runtimeRoot come from the shared owner; executable lookup verifies absolute paths or resolves a bare name against the sandbox PATH plus explicit overrides.
Linux process groups — a quoted wrapper starts each argv under exec setsid --wait and records its actual process-group id plus private status files beneath ctx.e2b.runtimeRoot/processes. The handle waits for that file instead of treating the SDK command PID as its published identity. Termination signals the negative recorded id with SIGTERM, waits the caller's graceMs, then escalates to SIGKILL and the SDK kill fallback; TERM delivery or probe failures also force that escalation. A failed transaction is observable through waitForExit() and may be retried. Before publication, cancellation uses the provisional SDK handle; if publication fails, rollback kills and verifies the provisional group before startup rejects. Service disposal terminates and joins every retained handle before the sandbox owner disposes.
Environment boundary — the wrapper starts from the sandbox command environment, removes ambient DSH_* and credential-shaped (*KEY*, *SECRET*, *TOKEN*) names, then restores every spec.env entry as an explicit caller opt-in. Host ambient variables never enter the sandbox implicitly. Private environment files are removed after consumption, and failed command or terminal setup removes its private state before rejecting.
Stdio projection — the remote wrapper branches raw bytes into optional bounded spill files, frames each live chunk as newline-delimited base64 ASCII, and the host incrementally restores bytes across arbitrary SDK callback boundaries. Pipe mode writes those bytes to host Node streams; inherit mode writes them to the harness process streams; collect mode retains a bounded host tail with offset reads. The wrapper publishes the direct command status before waiting for inherited writers; after graceMs, the adapter disconnects an incomplete SDK stream, withholds its partial spill, and returns that status while retaining the remote group for waitForExit() and termination. Batch and streaming stdin use the SDK handle.
Terminal sessions — spawnTerminal() uses E2B's byte PTY API, installs the exact argv and scrubbed environment through private mode-0600 files, reports the foreground process group, sends real signals, and tears down every group in the remote terminal session before settlement. Setup and teardown own the private state transaction, including failure cleanup. Prompt detection, scrollback, readiness, and owner policy remain in dsh-pty-local.

The base E2B image supplies the runtime and Bash/GNU utilities this adapter invokes: node, bash, setsid, ps, awk, tr, env, chmod, tee, head, rm, and kill. A custom template must retain compatible commands and E2B PTY support.

Model Experience

Indirectly, through consumer seams such as the Bash executor behind dsh-tool-bash, which render remote output, exit facts, background deltas, and spill paths.

KV Cache effect

No direct invalidation; the named consumers own any request-prefix changes.

Known Limitations and Deferred Work

The SDK still retains complete command output in host memory — E2B CommandHandle.stdout and .stderr accumulate the base64 transport even when this adapter exposes bounded raw-byte tails, so the subprocess seam's normal host-memory bound is not achieved and transport retention is larger than the source stream.
Synchronous-PID consumers are unsupported — pid remains -1 during remote startup; consumers that require a positive PID immediately, including the ACP child backend, cannot use this provider unchanged.
Reconnect does not reconstruct handles — remote PID/status/spill files survive a retained sandbox, but a new harness process does not rebuild live SubprocessHandle objects or output cursors from them.
Remote state accumulates when retained — process directories and valid spill files remain under .dsh-e2b; this POC supplies no retention sweep.
E2B exposes no signal fact — only an adapter-requested SIGTERM or SIGKILL is reported as a signal; every unrequested SDK exit remains an exit code, including values shaped like 128 + signal.
Exact terminal stdin-wait inspection is unavailable — E2B exposes the foreground process group but not the syscall evidence needed to prove it is waiting on fd 0, so the generic PTY backend falls back to controlled prompt markers and bounded silence.
Linux utility and E2B transport semantics are assumed — there is no Windows, arbitrary-template, escaped-session recovery, or network-partition fidelity layer.