npx skills add ...
npx skills add upstash/skills --skill upstash-box-js
npx skills add upstash/skills --skill upstash-box-js
Work with the @upstash/box TypeScript/JavaScript SDK for sandboxed cloud containers with AI agents, shell, filesystem, and git. Use when building with Upstash Box, creating sandboxed environments, running AI agents in containers, or orchestrating parallel boxes.
Sandboxed cloud containers with built-in AI agents, shell, filesystem, and git.
Set UPSTASH_BOX_API_KEY env var or pass apiKey to constructors.
Every run (agent, command, or code) returns a Run<T>:
The SDK tracks cwd client-side. All operations (exec, files, git, agent) run relative to it.
Lightweight, short-lived boxes (max 3 days). No agent, git, snapshot, or fork. Supports exec, files, cd, and snapshots only.
Expose box ports as public URLs with optional auth.
Attach MCP servers to the box agent.
/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 thoserun.exitCode is null for agent runs, only available for exec commandsbox.delete() is irreversible — snapshot first if you need the stategit.token in BoxConfig for private repos and PRsBox.fromSnapshot() creates a new box — it does not modify the originalimport { 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 ..." } },
})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 }]// 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 }
}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" })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 pathawait 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"] })// 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()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 })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)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: "..." } },
],
})