Error when run Fusion in local repo from the CLI

Technical Questions
1

Hi everyone,

I’m seeing this error when using Fusion Assistant via CLI:
codegen/completion endpoint: BadStatus403

Details:
@builder.io/dev-tools@latest (1.11.16)
Dev server: Vite at http://localhost:5173

Launch command:
npx “@builder.io/dev-tools@latest” launch --serverUrl http://localhost:5173
Fusion logs:
┌ fusion 1.11.16
│
◆ Logged in as space: Alireza BP Space
│
● :magnifying_glass_tilted_left: Setting up Builder.io server on port 48752
◆ :rocket: Builder.io server running at http://localhost:48752
● Proxying to existing dev server at http://localhost:5173…
● OPEN BROWSER: Builder.io: Visual Development Platform

Account: Pro plan, all Agent Credits available
React + Vite project, Builder initialized in App.tsx

import { builder } from “@builder.io/react”;
builder.init(import.meta.env.VITE_PUBLIC_BUILDER_KEY);

Observations:

  • Fusion works correctly in the web version (https://builder.io), without using the CLI.

  • The problem occurs only when using the CLI (launch command).

  • I have already verified that my Agent Credits are not exhausted.

  • Ports and URLs are consistent between CLI and dev server.

It seems like the CLI may be sending requests that are rejected by the endpoint, resulting in a 403 status. I am not sure if this is related to authentication, proxy setup, or another CLI-specific issue

2

Hello @sajjad_chahardoli,

Could you please try starting a new chat and see if that resolves the issue?

In addition, here are a few targeted steps that may help isolate or fix the problem:

1. Reauthenticate via the CLI
Refresh your authentication token by running:

npx "@builder.io/dev-tools@latest" auth

Then verify your status with:

npx "@builder.io/dev-tools@latest" auth status

If successful, relaunch Fusion via the CLI.

2. Verify Allowlist Configuration
All Fusion projects require access to the following URLs. Please ensure these are included in your application or organization’s allowlist:

  • firestore.googleapis.com

  • firebasestorage.googleapis.com

  • *.builder.io

  • *.builder.codes

  • *.fly.dev

Please let us know the outcome after trying these steps so we can assist further if needed.

Best regards,

3

Since the web app works, I’d suspect a CLI authentication issue rather than your Vite setup. I’d try re-authenticating the CLI first. When debugging issues like this, I also like to verify the underlying API requests separately with Apidog to confirm whether the problem is with the API itself or the CLI layer.