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1

Install the CLI

npm install -g @jelou/cli
Verify the installation:
jelou --version
2

Authenticate

You need a personal access token (create one in the Jelou dashboard).
jelou login
# Paste your access token: ****
# ✓ Logged in
In CI you can pass the token directly: jelou login --token jfn_pat_your_token
3

Initialize a project

Create a directory and run jelou init:
mkdir query-customer && cd query-customer
jelou init
# ? Function slug: query-customer
# ? Description: Looks up customer information for the WhatsApp bot
# ? Create new or link existing? Create new
# ✓ Created query-customer
This generates the base files:
FilePurpose
index.tsYour main function
jelou.jsonProject configuration
deno.jsonSDK import map
.envLocal environment variables
4

Write your function

Replace the contents of index.ts with a function that looks up customers by phone:
index.ts
import { define, z } from "@jelou/functions";

export default define({
  name: "query-customer",
  description: "Looks up customer information by phone number for the support bot",
  input: z.object({
    phone: z.string().min(10).describe("Customer phone number"),
  }),
  output: z.object({
    name: z.string(),
    email: z.string(),
    plan: z.string(),
    balance: z.number(),
  }),
  handler: async (input, ctx) => {
    ctx.log("Looking up customer", {
      phone: input.phone,
      company: ctx.company.id,
    });

    const apiKey = ctx.env.get("CRM_API_KEY");
    const res = await fetch(
      `https://crm.example.com/api/customers?tel=${input.phone}`,
      { headers: { Authorization: `Bearer ${apiKey}` } },
    );
    const customer = await res.json();

    return {
      name: customer.name,
      email: customer.email,
      plan: customer.plan,
      balance: customer.balance,
    };
  },
});
5

Run locally

Start the development server:
jelou dev
# ▸ Listening on http://localhost:3000
# ▸ Watching for changes...
Your server reloads automatically when you edit files.
6

Test with curl

In another terminal, send a request:
curl -X POST http://localhost:3000 \
  -H "Content-Type: application/json" \
  -d '{"phone": "593987654321"}'
Response:
{
  "name": "Maria Garcia",
  "email": "[email protected]",
  "plan": "Premium",
  "balance": 150.00
}
You can also test the MCP endpoint at http://localhost:3000/mcp and the health check at http://localhost:3000/__health.
7

Configure secrets

Before deploying, add the environment variables your function needs:
jelou secrets set query-customer CRM_API_KEY=YOUR_CRM_API_KEY
# ✓ Set 1 secret
8

Deploy to production

jelou deploy
# ▸ Files: index.ts (1.2 KB), jelou.json (98 B), deno.json (65 B)
# ? Deploy query-customer? (Y/n) y
# ✓ Deployed to https://query-customer.fn.jelou.ai
# ⚠ A default runtime token was created for this function.
#   Save it now — it will not be shown again.
# ▸ Token    jfn_rt_abc123...
Save the token — it will not be shown again. You need it to call your function in production.
Your function is now available in production. Jelou AI agents can invoke it as an MCP tool automatically.
9

Verify in production

curl -X POST https://query-customer.fn.jelou.ai \
  -H "Content-Type: application/json" \
  -H "X-Jelou-Token: jfn_rt_abc123..." \
  -d '{"phone": "593987654321"}'
Monitor logs in real time:
jelou logs query-customer

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Next steps