Keep real keys private with LlamaIndex.

# pip install llama-index-core llama-index-llms-openai deny-sh requests
import os, asyncio, requests, json
from llama_index.core.tools import FunctionTool
from llama_index.core.agent.workflow import FunctionAgent
from llama_index.llms.openai import OpenAI
from deny_sh import vault_get

def get_invoice(id: str) -> str:
    """Look up a Stripe invoice by id and return a narrowed summary."""
    # resolve the credential INSIDE the tool boundary
    stripe_key = vault_get("stripe-prod", os.environ["VAULT_PW"])
    r = requests.get(
        f"https://api.stripe.com/v1/invoices/{id}",
        headers={"Authorization": f"Bearer {stripe_key}"},
    )
    # narrowed DTO: never return raw upstream response bodies
    body = r.json()
    return json.dumps({
        "id": body.get("id"),
        "amount_due": body.get("amount_due"),
        "status": body.get("status"),
    })

invoice_tool = FunctionTool.from_defaults(fn=get_invoice)

agent = FunctionAgent(
    tools=[invoice_tool],
    llm=OpenAI(model="gpt-4o"),
    system_prompt="You are a billing assistant.",
)

async def main():
    result = await agent.run("Look up invoice in_1Abc123XYZ")
    print(result)

asyncio.run(main())

// npm install llamaindex @llamaindex/workflow deny-sh@^2.2.0 zod
import { tool, OpenAI } from 'llamaindex';
import { agent } from '@llamaindex/workflow';
import { vaultGet } from 'deny-sh/client';
import { z } from 'zod';

const invoiceTool = tool({
  name: 'get_invoice',
  description: 'Look up a Stripe invoice by id and return a narrowed summary',
  parameters: z.object({ id: z.string() }),
  execute: async ({ id }) => {
    // resolve the credential INSIDE the tool boundary
    const stripeKey = await vaultGet('stripe-prod', process.env.VAULT_PW!);
    const r = await fetch(`https://api.stripe.com/v1/invoices/${id}`, {
      headers: { Authorization: `Bearer ${stripeKey}` },
    });
    // narrowed DTO: never return raw upstream response bodies
    const body = await r.json();
    return JSON.stringify({
      id: body.id,
      amount_due: body.amount_due,
      status: body.status,
    });
  },
});

const billingAgent = agent({
  tools: [invoiceTool],
  llm: new OpenAI({ model: 'gpt-4o' }),
  systemPrompt: 'You are a billing assistant.',
});

const result = await billingAgent.run('Look up invoice in_1Abc123XYZ');
console.log(result.message.content);

from llama_index.core.tools import FunctionTool
from llama_index.core.agent.workflow import FunctionAgent
from llama_index.llms.openai import OpenAI
from deny_sh import vault_get
import requests, json

def tools_for_tenant(tenant_pw: str, tenant_api_key: str):
    def get_invoice(id: str) -> str:
        """Look up a Stripe invoice by id for this tenant."""
        # closure captures tenant_pw + tenant_api_key :  no fallback to shared key
        stripe_key = vault_get("stripe-prod", tenant_pw,
            api_key=tenant_api_key)
        r = requests.get(f"https://api.stripe.com/v1/invoices/{id}",
            headers={"Authorization": f"Bearer {stripe_key}"})
        body = r.json()
        return json.dumps({"id": body.get("id"),
            "amount_due": body.get("amount_due"), "status": body.get("status")})
    return [FunctionTool.from_defaults(fn=get_invoice)]

# per-request: build a fresh agent with this tenant's tools
async def handle_request(tenant_pw: str, tenant_api_key: str, query: str):
    tools = tools_for_tenant(tenant_pw, tenant_api_key)
    ag = FunctionAgent(tools=tools, llm=OpenAI(model="gpt-4o"))
    return await ag.run(query)