Cloudflare Workers Builds fails with Could not detect a directory containing static files

[NeumoNeumo]

Hi, when deploying a repo based on cfnewup through Cloudflare Workers Builds / Git integration, the deployment fails with Wrangler 4.x.

Reproduction

Cloudflare build settings:

Build command: None
Deploy command: npx wrangler deploy
Root directory: /

The repo contains _worker.js.

The deployment reaches Wrangler and then fails:

Executing user deploy command: npx wrangler deploy

npm warn exec The following package was not found and will be installed: wrangler@4.128.0

⛅️ wrangler 4.128.0
────────────────────

✘ [ERROR] Could not detect a directory containing static files (e.g. html, css and js) for the project

Failed: error occurred while running deploy command

Possible Cause

_worker.js is recognized specially by Cloudflare Pages, but wrangler deploy for a normal Worker needs a Worker entrypoint to be specified.

The current wrangler.toml does not appear to declare _worker.js as main, so current Wrangler tries project/static asset auto-detection instead of treating _worker.js as the Worker entrypoint.

Suggested fix

Declare _worker.js explicitly in wrangler.toml:

main = "_worker.js"
compatibility_date = "2026-01-20"

Alternatively, the deployment command would need to specify the entrypoint explicitly:

npx wrangler deploy ./_worker.js

I think adding main = "_worker.js" upstream is preferable, since then Git-connected Cloudflare Workers deployments work with the standard:

npx wrangler deploy

My current edition that works: https://github.com/NeumoNeumo/cfpau/tree/main

[NeumoNeumo]

One more concern with the current Workers Builds flow: deployments use wrangler deploy, so Dashboard configuration can be affected.

For normal environment variables, adding this should preserve Dashboard-managed values:

"keep_vars": true

However, keep_vars does not preserve KV bindings. For example, the C KV binding should be explicitly declared in wrangler.jsonc:

"kv_namespaces": [
  {
    "binding": "C",
    "id": "USER_KV_NAMESPACE_ID"
  }
]

Since the KV namespace ID is user-specific, this probably needs to be documented as a post-deployment configuration step.