---
title: "Sandbox"
description: "LangBot Box Runtime gives the built-in Agent command and file tools with a choice of sandboxed or trusted-host backends."
---

Box Runtime gives the built-in Agent one execution interface for running commands, reading and writing files, and hosting long-lived processes. Everyday Agent use cases (data processing, file operations, running user code, hosting stdio MCP) all rely on it. Docker, nsjail, and E2B provide sandbox isolation; the explicitly selected Host backend is for trusted local development and provides no isolation.

Once Box is enabled, the built-in Agent automatically gains six tools — no need to wire each one into the pipeline.

## Built-in Tools

| Tool | Purpose |
|------|---------|
| `exec` | Run shell commands inside the sandbox |
| `read` | Read workspace files |
| `write` | Create or overwrite files |
| `edit` | Modify files via string replacement |
| `glob` | Find files by glob pattern |
| `grep` | Search file contents by regex |

`exec` runs in the selected Box backend; the other five operate directly on the workspace directory mapped to `/workspace`. With Host selected, commands also run directly on the Box Runtime host.

<Note>
These tools target the built-in Agent. When using external runners such as Dify, n8n, Langflow, or Coze, use that platform's own tool mechanism.
</Note>

## Sandbox Scope

The pipeline's AI configuration lets you choose how the sandbox is shared across messages. The default "per chat" works for most cases.

| Scope | Template | Shared across |
|-------|----------|---------------|
| Global | `{global}` | All users share one sandbox |
| Per chat (default) | `{launcher_type}_{launcher_id}` | Same group or DM shares one |
| Per user | `{launcher_type}_{launcher_id}_{sender_id}` | Each member in a group is isolated |
| Per conversation | `{launcher_type}_{launcher_id}_{conversation_id}` | Isolated by conversation |
| Per message | `{query_id}` | Fully stateless |

<Warning>
Commands within the same scope share filesystem state. Choose "per message" for a separate workspace. Scope controls session reuse; it is not a security boundary. Host has no host-level isolation even when different scopes are used.
</Warning>

## Lifecycle

| Condition | Behavior |
|-----------|----------|
| Idle for more than 5 minutes | Cleaned up automatically |
| Box-managed processes running (e.g. stdio MCP) | Kept alive until those processes exit |
| `persistent: true` configured | Never cleaned up automatically |

These lifecycle rules also apply to Host. Cleanup terminates the session's managed process trees and removes its temporary session directory. A durable workspace mapped under `box.local.host_root` is not deleted as temporary state. Runtime shutdown and explicit session deletion also perform cleanup.

## Quick Start

Trusted local development on Linux / macOS can select Host without installing Docker:

1. **Edit `config.yaml`**:
   ```yaml
   box:
     enabled: true
     backend: 'host'
     local:
       host_root: './data/box'
   ```
2. **Start LangBot**: Box Runtime is enabled automatically
3. **In the pipeline**, select the built-in Agent plus a model that supports function calling

The Agent will then automatically receive the six tools. See [Sandbox Configuration](./config) for details.

<Warning>
Host executes commands directly with the LangBot / Box Runtime user's permissions and must only process trusted input. To execute untrusted code, set `backend` to `local` (auto-pick Docker / Nsjail), `docker`, `nsjail`, or `e2b`.
</Warning>

## Disabling Box

Set `box.enabled: false`. Everything that depends on the sandbox (built-in tools, Skill create/edit/activate, stdio MCP) is disabled together; MCP servers in http/sse mode are unaffected.

## Next Steps

- [Sandbox Configuration](./config) — backends, security profiles, mounts, environment variables
- [Runtimes & Extensions Compared](./runtime-relationships) — how the sandbox, Skills, MCP, and plugins divide responsibilities