upstash-box-js

@upstash/box SDK

Sandboxed cloud containers with built-in AI agents, shell, filesystem, and git.

Install & Setup

npm install @upstash/box

Set UPSTASH_BOX_API_KEY env var or pass apiKey to constructors.

Box Lifecycle

import { Box, Agent, ClaudeCode, BoxApiKey } from "@upstash/box"

// Create with agent + git + env vars
const box = await Box.create({
  runtime: "node", // "node" | "python" | "golang" | "ruby" | "rust"
  agent: {
    harness: Agent.ClaudeCode, // Agent.Codex | Agent.OpenCode
    model: ClaudeCode.Sonnet_4_5,
    // apiKey options:
    //   omit          → server decides which key to use
    //   BoxApiKey.UpstashKey  → use Upstash-provided LLM key
    //   BoxApiKey.StoredKey   → use key previously stored via Upstash Console
    //   "sk-..."      → direct API key string
    apiKey: BoxApiKey.UpstashKey,
  },
  git: { // all fields optional
    token: process.env.GITHUB_TOKEN, // alternatively link your GitHub account via Upstash Console
    userName: "Bot",
    userEmail: "[email protected]",
  },
  env: { DATABASE_URL: "..." },
  skills: ["upstash/qstash-js"], // GitHub repos as agent skills
})

// Reconnect, list, delete, pause/resume
const same = await Box.get(box.id)
const all = await Box.list()
await box.pause()
await box.resume()
await box.delete()  // irreversible
const { status } = await box.getStatus()

Agent Runs

import { z } from "zod"

// Structured output with Zod schema
const run = await box.agent.run({
  prompt: "Review the code for security issues",
  responseSchema: z.object({
    verdict: z.enum(["approved", "changes_requested"]),
    findings: z.array(z.object({
      severity: z.enum(["high", "medium", "low"]),
      file: z.string(),
      issue: z.string(),
    })),
  }),
  timeout: 120_000,
  maxRetries: 2,
  onToolUse: (tool) => console.log(tool.name, tool.input),
})

run.status  // "running" | "completed" | "failed" | "cancelled" | "detached"
run.result  // typed from schema
run.cost    // { inputTokens, outputTokens, computeMs, totalUsd }

// Streaming
const stream = await box.agent.stream({
  prompt: "Build a REST API",
})
for await (const chunk of stream) { console.log(chunk) }

// Fire-and-forget with webhook
await box.agent.run({
  prompt: "Run tests",
  webhook: { url: "https://example.com/hook", headers: { Authorization: "Bearer ..." } },
})

Run Fields

Every run (agent, command, or code) returns a Run<T>:

const run = await box.exec.command("npm test")
run.id        // run ID
run.status    // "completed" | "failed" | ...
run.result    // string output (or typed T with responseSchema)
run.exitCode  // number | null (null for agent runs)
run.cost      // { inputTokens, outputTokens, computeMs, totalUsd }

await run.cancel()          // cancel a running run
const logs = await run.logs() // [{ timestamp, level, message }]

Shell Execution

// Run commands
const run = await box.exec.command("echo hello && ls -la")

// Run code snippets — lang: "js" | "ts" | "python"
const run2 = await box.exec.code({ code: "console.log(1+1)", lang: "js", timeout: 10_000 })

// Streaming shell
const stream = await box.exec.stream("npm run build")
for await (const chunk of stream) {
  // chunk: { type: "output", data } | { type: "exit", exitCode, cpuNs }
}

Filesystem

await box.files.write({ path: "/workspace/home/app.js", content: "console.log('hi')" })
const content = await box.files.read("/workspace/home/app.js")
const entries = await box.files.list("/workspace/home") // [{ name, path, size, is_dir, mod_time }]

// Binary files — use encoding: "base64" for read and write
await box.files.write({ path: "/workspace/home/image.png", content: base64String, encoding: "base64" })
const b64 = await box.files.read("/workspace/home/image.png", { encoding: "base64" })

// Upload local files, download box files
await box.files.upload([{ path: "./local/file.txt", destination: "/workspace/home/file.txt" }])
await box.files.download({ folder: "./output" })

cd / Working Directory

The SDK tracks cwd client-side. All operations (exec, files, git, agent) run relative to it.

box.cwd // current working directory (starts at /workspace/home)
await box.cd("my-repo")     // relative to current cwd
await box.cd("/workspace/home/other") // absolute path

Git

await box.git.clone({ repo: "github.com/org/repo", branch: "main" })
await box.cd("repo") // cd into cloned repo

const status = await box.git.status()
const diff = await box.git.diff()
const { sha } = await box.git.commit({ message: "fix: resolve bug" })
await box.git.push({ branch: "feature/fix" })

await box.git.checkout({ branch: "release/v2" })
const pr = await box.git.createPR({ title: "Fix bug", body: "...", base: "main" })
// pr: { url, number, title, base }

// Arbitrary git commands
const { output } = await box.git.exec({ args: ["log", "--oneline", "-5"] })

Snapshots & Fork

// Snapshot — checkpoint workspace state
const snap = await box.snapshot({ name: "after-setup" })
// snap: { id, name, box_id, size_bytes, status, created_at }

const restored = await Box.fromSnapshot(snap.id)
const snaps = await box.listSnapshots()
await box.deleteSnapshot(snap.id)

// Fork — clone live state into a new box
const forked = await box.fork()

EphemeralBox

Lightweight, short-lived boxes (max 3 days). No agent, git, snapshot, or fork. Supports exec, files, cd, and snapshots only.

import { EphemeralBox } from "@upstash/box"

const ebox = await EphemeralBox.create({
  runtime: "python",
  ttl: 3600,  // seconds, max 259200 (3 days)
  env: { API_KEY: "..." },
})

ebox.expiresAt // unix timestamp when auto-deleted
await ebox.exec.command("python -c 'print(1+1)'")
await ebox.exec.code({ code: "print('hi')", lang: "python" })
await ebox.files.write({ path: "/workspace/home/data.json", content: "{}" })
await ebox.cd("subdir")
await ebox.delete()

// Restore from snapshot
const ebox2 = await EphemeralBox.fromSnapshot(snap.id, { ttl: 7200 })

Public URLs

Expose box ports as public URLs with optional auth.

const publicURL = await box.getPublicURL(3000)
// publicURL: { url: "https://{id}-3000.preview.box.upstash.com", port }

const authed = await box.getPublicURL(3000, { bearerToken: true })
// authed: { url, port, token }

const basic = await box.getPublicURL(3000, { basicAuth: true })
// basic: { url, port, username, password }

const { publicURLs } = await box.listPublicURLs()
await box.deletePublicURL(3000)

MCP Servers

Attach MCP servers to the box agent.

const box = await Box.create({
  agent: { harness: Agent.ClaudeCode, model: ClaudeCode.Sonnet_4_5 },
  mcpServers: [
    { name: "fs", package: "@modelcontextprotocol/server-filesystem" },
    { name: "custom", url: "https://mcp.example.com/sse", headers: { Authorization: "..." } },
  ],
})

Gotchas

• Default working directory is /workspace/home, not /home or /
• box.cd() is client-side tracking — it validates the path exists but doesn't change the box's shell cwd. All SDK methods use it automatically.
• EphemeralBox does NOT support agent, git, fork, or public URLs — use full Box for those
• run.exitCode is null for agent runs, only available for exec commands
• box.delete() is irreversible — snapshot first if you need the state
• Git operations require git.token in BoxConfig for private repos and PRs
• Box.fromSnapshot() creates a new box — it does not modify the original