@agentkit-js/openai-agents

@agentkit-js/openai-agents

Drop agentkit-js sandbox kernels into the OpenAI Agents JS SDK as a native tool. Edge-safe code execution, one capability manifest, runs on Cloudflare Workers / Vercel Edge / Node — no E2B sandbox required.

Why this exists

The 2026-04 OpenAI Agents JS release introduced a first-party SandboxAgent with Unix-local, Docker, and hosted-container execution clients. That covers the case where a host process is available and you want OS-level isolation. It does not cover:

• Cloudflare Workers / Vercel Edge / browser tabs (no host process for Unix-local; Docker isn't a thing on the edge).
• Air-gapped / offline deployments where reaching a hosted container is not allowed.
• Workloads where 50 ms is too long for cold start and per-second container billing dominates the cost.

The agentkit kernels live below the OS line — QuickJS-in-WASM, Pyodide-in-WASM, or Wasmtime — so they run wherever JS runs. This package binds them to the Agents JS Tool shape.

Install

npm install @openai/agents @agentkit-js/openai-agents @agentkit-js/kernel-quickjs \
  quickjs-emscripten @jitl/quickjs-wasmfile-release-sync zod

One-shot snippet evaluation

import { Agent } from "@openai/agents";
import { sandboxedJsAgentTool } from "@agentkit-js/openai-agents";
import { QuickJSKernel } from "@agentkit-js/kernel-quickjs";

const agent = new Agent({
  name: "math-helper",
  tools: [
    sandboxedJsAgentTool({
      kernel: new QuickJSKernel(),
      capabilities: { cpuMs: 5000 },
    }),
  ],
});

Code-mode: collapse N tools

import { codeModeAgentTool } from "@agentkit-js/openai-agents";
import { ToolRegistry } from "@agentkit-js/core";

const tools = new ToolRegistry();
// …register downstream tools…

const portalTool = codeModeAgentTool({
  kernel: new QuickJSKernel(),
  tools,
  capabilities: { allowedHosts: ["api.example.com"] },
});

const agent = new Agent({ name: "ops", tools: [portalTool] });
// Model sees ONE tool; in-sandbox scripts call N tools via callTool(...).

Capability manifest

Same CapabilityManifest as the other adapters — see docs/guides/code-mode.md.

When to pick this over SandboxAgent

Need	OpenAI SandboxAgent	@agentkit-js/openai-agents
Cloudflare Workers / Vercel Edge	❌ requires host process	✅ WASM kernel runs in-isolate
Native binaries / full POSIX	✅ Docker / hosted	❌ language-level only
Cold start	~200–800 ms (container)	~50 ms (WASM)
Cost per call	per-second container billing	$0 (in-process)
Offline / air-gapped	❌	✅

Use both: SandboxAgent for "I need bash + git", codeModeAgentTool for "the model wants to do math / parse JSON / chain tool calls".

See also

• @agentkit-js/aisdk — same kernels for Vercel AI SDK
• @agentkit-js/claude-agent-sdk — same kernels for Anthropic Claude Agent SDK
• @agentkit-js/mastra-sandbox — same kernels as a Mastra sandbox provider