I have reproduced the issue on the latest CLI version.
Yes, I am on the latest version
I have searched existing posts and this report is not a duplicate.
Yes, this isn’t a duplicate
In which of these areas are you experiencing a problem?
App
Extension
Expected behavior
“shopify app dev” runs after installing new extension with no modifications
Actual behavior
crashes with error:
Unexpected end of JSON input
not sure when this could have started happening, other types of extensions within the same app works fine (3 function (cart transform, checkout validation, discount extensions))
Reproduction steps
-
run “shopify app generate extension” > give name and choose theme app extension, no modifications whatsoever
-
run shopify app dev, get JSON error
-
removing the extension and running “shopify app dev”, runs with no issues
Verbose output
last two lines from running shopify app dev --verbose before the crash:
2026-07-10T22:02:08.747Z: Reusing crawler signature “Shopify CLI” for xxxx.myshopify.com (present: Signature, Signature-Input, Signature-Agent; missing: none).
2026-07-10T22:02:08.978Z: Request to https://xxxx.myshopify.com/admin/api/2026-07/graphql.json completed in 240 ms
Operating system
MacOS / shopify-cli via homebrew
CLI version
4.4.0
Shell
zsh
Nodejs version
v23.9.0
What language and version are you using in your application?
js?