vercel deploy uploads ~300MB for non-prebuilt Next.js app when .vercel/repo.json exists at repo root

Summary

In a PNPM monorepo, running vercel deploy --prod for a non-prebuilt Next.js app triggers an upload of ~300 MB.
This only happens when a .vercel/repo.json file exists at the repository root (needed to deploy other prebuilt apps).
Removing the file avoids the huge upload, but then I can’t deploy the prebuilt apps in the same monorepo.

I need to keep .vercel/repo.json for the prebuilt apps and deploy this one app as non-prebuilt (for sharp/image support), but the CLI behavior forces a 300 MB upload.

Reproduction

Monorepo layout (simplified)

/<monorepo-root>
  /.vercel/repo.json                  <-- required for other prebuilt apps
  /<path-to-apps>/
    /<prebuilt-app-1>                 <-- prebuilt app
    /<prebuilt-app-2>                 <-- prebuilt app
    /<non-prebuilt-app>               <-- Next.js app that should build on Vercel

/<path-to-apps>/<non-prebuilt-app>/package.json

{
  "name": "<non-prebuilt-app>",
  "private": true,
  "scripts": {
    "dev": "next dev",
    "build": "next build",
    "start": "next start",
    "lint": "next lint",
    "deploy": "vercel deploy --prod"
  },
  "dependencies": {
    "next": "14.3.0-canary.42",
    "react": "18",
    "react-dom": "18",
    "sharp": "0.34.3"
  },
  "devDependencies": {
    "@types/node": "^20",
    "@types/react": "^18",
    "@types/react-dom": "^18",
    "eslint": "^8",
    "eslint-config-next": "14.3.0-canary.42",
    "postcss": "^8",
    "tailwindcss": "^3.4.1",
    "typescript": "^5"
  }
}

Root .vercel/repo.json (excerpt)

{
  "orgId": "<org_id>",
  "remoteName": "origin",
  "projects": [
    { "id": "<project_id_1>", "name": "<prebuilt-app-1>", "directory": "<path-to-apps>/<prebuilt-app-1>" },
    { "id": "<project_id_2>", "name": "<prebuilt-app-2>", "directory": "<path-to-apps>/<prebuilt-app-2>" },
    { "id": "<project_id_3>", "name": "<non-prebuilt-app>", "directory": "<path-to-apps>/<non-prebuilt-app>" }
  ]
}

Commands

cd <path-to-apps>/<non-prebuilt-app>
vercel deploy --prod

Observed (Vercel CLI 41.6.0)

Vercel CLI 41.6.0
: Uploading [--------------------] (10.0MB/303MB)

With .vercel/repo.json present, it uploads ~300 MB.
If I temporarily remove .vercel/repo.json, the upload doesn’t happen and deploy behaves like a normal server build.

Expected behavior

• For a non-prebuilt Next.js app, the CLI should not upload hundreds of MB; it should build on Vercel (same behavior as when .vercel/repo.json is absent).
• The presence of .vercel/repo.json should not change deploy behavior for apps not using --prebuilt.

Actual behavior

• With .vercel/repo.json present, vercel deploy --prod uploads ~300 MB.
• Removing .vercel/repo.json avoids the upload but breaks prebuilt deploys for other apps in the monorepo.

Why this matters

• The non-prebuilt app must build on Vercel to use runtime modules like sharp.
• I still need .vercel/repo.json to deploy other apps as prebuilt.
• Currently I can’t do both.

Environment

• Vercel CLI: 41.6.0
• Next.js: 14.3.0-canary.42
• Node: 18.x
• Package manager: pnpm
• OS: macOS
• Monorepo: yes

Hypothesis

When .vercel/repo.json exists, the CLI may treat the deploy as if it were prebuilt or expand the workspace context, causing a massive upload from the monorepo even without --prebuilt.

Request

• Confirm whether this is a CLI bug with project resolution when .vercel/repo.json is present in a monorepo.

• Provide a flag or config to force non-prebuilt behavior for a specific app while keeping .vercel/repo.json.

• Share any workaround that allows:

  1. keeping .vercel/repo.json for prebuilt apps, and
  2. deploying this app without the 300 MB upload.