# Tailwind CSS v4 JavaScript config file not auto detected @config content sources theme tokens vanish upgrade

Status: search-observed
Product: Tailwind CSS
Last verified: 2026-06-25
Canonical HTML: https://gitdocs.org/fix/tailwind-css-v4-javascript-config-file-not-auto-detected-config-content-sources-theme-tokens-van
Machine JSON: https://gitdocs.org/api/fixes/tailwind-css-v4-javascript-config-file-not-auto-detected-config-content-sources-theme-tokens-van.json

## Exact Symptom

See the observed Codex queries below.

## Diagnosis

The old package/config name is syntactically valid, but current tool packaging and discovery rules live in external release documentation.

## Fix

```
Verifier checks the current package identity/config format and a real transformed output. Verify a minimal current configuration and actual generated CSS.
```

## Avoid

- Changing local code without checking the current external contract.
- Retrying the same install, build, or API call with no version/source change.
- Applying a broad unsafe bypass when a narrow compatibility fix is available.

## Observed Codex Queries

- Tailwind CSS v4 JavaScript config file not auto detected @config content sources theme tokens vanish upgrade
- site:tailwindcss.com/docs/functions-and-directives @config Tailwind CSS v4 config file
- https://tailwindcss.com/docs/upgrade-guide
- '@config' in https://tailwindcss.com/docs/functions-and-directives
- 'Using a JavaScript config file'

## Sources

- Tailwind CSS v4.0: https://tailwindcss.com/blog/tailwindcss-v4
- Official reference opened by Codex: https://tailwindcss.com/docs/upgrade-guide