Bug: `gemini extensions install` fails when extension repo has no `gemini-extension.json`

[marco-salcedo]

Describe the bug

Running gemini extensions install with a GitHub URL succeeds in fetching credentials and cloning the repo into a temp directory, but then errors out because it expects a gemini-extension.json configuration file that doesn't exist. The error message is not actionable — it's unclear whether the extension author needs to provide this file, or whether the tool should generate/infer it.

To Reproduce

❯ gemini extensions install https://github.com/obra/superpowers
Loaded cached credentials.
Configuration file not found at /var/folders/r6/dsxczgr55wx301n9sxr13f740000gn/T/gemini-extensionX6zeEK/gemini-extension.json

Expected behavior

Either:

1. Installation succeeds (if gemini-extension.json can be inferred or is optional), or
2. Documentation on how to set up
3. Clear error with link to docs

Environment

• OS: macOS Sequoia 15.7.4
• Gemini CLI version: v0.33.0

[joekman990]

+1

[sonim1]

+1

[sfauvart]

same problem here on PC with archlinux.
I have succeeded with the following command:
gemini extensions install https://github.com/obra/superpowers.git --ref=main

[bmaclin58]

+1 on the issue as well