lelu
Integrations

OpenAI

Gate OpenAI function calls and tool-use requests through Lelu before they execute. Works with the Assistants API, Chat Completions with tools, and the Agents SDK.

Installation

terminal
npm install lelu-agent-auth openai

Chat Completions with tool calls

Try send_email in sandbox

After the model returns a tool_calls response, authorize each call through Lelu before executing the underlying function.

agent.ts
import OpenAI from "openai";
import { createClient } from "lelu-agent-auth";

const openai = new OpenAI({ apiKey: process.env.OPENAI_API_KEY });
const lelu = createClient({ apiKey: process.env.LELU_API_KEY! });

const response = await openai.chat.completions.create({
  model: "gpt-4o",
  messages,
  tools,
});

for (const call of response.choices[0].message.tool_calls ?? []) {
  const decision = await lelu.authorize({
    tool: call.function.name,
    context: call.function.arguments,
  });

  if (decision.decision === "deny") {
    throw new Error(`Tool ${call.function.name} was denied: ${decision.reason}`);
  }

  if (decision.decision === "human_review") {
    await waitForApproval(decision.requestId); // your approval flow
  }

  // safe to execute
  await dispatchTool(call);
}

OpenAI Agents SDK

Wrap each tool in a Lelu guard using the withLelu helper.

agent.ts
import { Agent, tool } from "@openai/agents";
import { withLelu } from "lelu-agent-auth/openai";

const sendEmail = withLelu(
  tool({
    name: "send_email",
    description: "Send an email to a user",
    parameters: z.object({ to: z.string(), body: z.string() }),
    execute: async ({ to, body }) => sendMailActual(to, body),
  })
);

const agent = new Agent({ tools: [sendEmail] });

Environment variables

.env
OPENAI_API_KEY=sk-...
LELU_API_KEY=lelu_sk_...
Previous: QuickstartNext: Anthropic