You are getting an HTTP 400 with “Invalid project resource name projects” because Antigravity is calling the API with an empty project id after switching accounts. The project selection UI is missing, so auto provisioning never wrote a default project and the client falls back to projects with no id.

Fix HTTP 400 Invalid project resource name projects in Antigravity

Users report that Antigravity keeps sending requests to projects with an empty name, returning a 400 error. After switching accounts, the app does not display a project picker and fails to persist a valid project id, even after cleaning local folders and trying antigravity auth login –force-project-sync. If your error is instead about account eligibility, see our quick checklist here: account not eligible troubleshooting.

Solution Overview

Aspect	Detail
Root Cause	No default Google Cloud project is set after account switch, so requests are sent to projects with an empty id
Primary Fix	Clear local Antigravity state, set a valid project id, then reauthenticate and force a project sync
Complexity	Easy
Estimated Time	10 to 15 minutes

Primary Fix Set a valid Google Cloud project and resync Antigravity

Step-by-Step Solution

1. Identify a valid Google Cloud project id

• A valid id is lowercase, contains letters numbers and dashes, and matches what you see in Google Cloud Console Project settings.
• If you have the Google Cloud CLI, list projects:

gcloud projects list

• Install or update gcloud if needed: https://cloud.google.com/sdk/docs/install

2. Set the project id in your environment Set this to the exact project id you will use. Windows PowerShell:

setx GOOGLE_CLOUD_PROJECT "your-project-id"

macOS or Linux:

echo 'export GOOGLE_CLOUD_PROJECT=your-project-id' >> ~/.zshrc
source ~/.zshrc
or if you use bash:
echo 'export GOOGLE_CLOUD_PROJECT=your-project-id' >> ~/.bashrc
source ~/.bashrc

Optionally tell gcloud the same default, which many SDKs read:

gcloud config set project your-project-id

Reference: https://cloud.google.com/sdk/docs/configurations 3. Fully clear Antigravity local state Quit Antigravity completely first. Windows PowerShell:

Remove-Item -Recurse -Force "$env:APPDATA\Antigravity" -ErrorAction SilentlyContinue
Remove-Item -Recurse -Force "$env:LOCALAPPDATA\Antigravity" -ErrorAction SilentlyContinue
Remove-Item -Recurse -Force "$HOME\.antigravity" -ErrorAction SilentlyContinue

macOS or Linux:

rm -rf "$HOME/.antigravity"
rm -rf "$HOME/Library/Application Support/Antigravity"

4. Reauthenticate and force a project sync Use the same Google account that owns or has access to the project you set above.

antigravity auth logout
antigravity auth login --force-project-sync

5. Relaunch Antigravity and verify calls include your project id Open the app and trigger any action that previously failed. The requests should now include projects/your-project-id rather than projects with no id. If you also hit temporary capacity messages during this step, see this note on timing out and retries: servers under high traffic.

Alternative Fixes and Workarounds

Create a project and attach billing if you do not have one

• In Google Cloud Console, create a new project and attach billing, then repeat Steps 2 to 5 with this new project id.
• Project creation guide: https://cloud.google.com/resource-manager/docs/creating-managing-projects

Use gcloud application default credentials if your environment relies on them

gcloud auth application-default login
gcloud config set project your-project-id

Restart Antigravity and try again. Update Antigravity to the latest build Older builds may hide the project picker and not retry auto provisioning correctly. Update to the newest version, then repeat Steps 2 to 5. If your workspace or Stitch content refuses to load If the app UI still does not surface your project or assets, review this checklist: project not loading in Stitch.

Troubleshooting Tips

• Confirm the variable is set correctly

– Windows: “` echo %GOOGLE_CLOUD_PROJECT% “` – macOS or Linux: “` echo $GOOGLE_CLOUD_PROJECT “` – The output must exactly match your project id

• Verify you have permission on the project

– You need at least viewer and any roles Antigravity requires in that project – If you switched accounts, ensure the new account has access

• Ensure required Google Cloud APIs are enabled for your project

– Open the Cloud Console APIs and Services page and enable the services Antigravity depends on

• Clear cached Google credentials if mismatched

“` gcloud auth revoke –all gcloud auth login gcloud auth application-default revoke gcloud auth application-default login “`

• Check for interfering proxies or VPNs

– Disable and retry to rule out request rewriting that can drop headers

Best Practices

• Keep a single primary Google account for Antigravity work to avoid silent context switches.
• Pin a default project with GOOGLE_CLOUD_PROJECT and gcloud config set project to make the context explicit.
• Do not rely solely on auto provisioning. Always verify the project id after sign in.
• Document your team’s project id and permissions so new sign ins are consistent.

If you see a different eligibility message before you can pick a project, this checklist helps you clear account gating quickly: fix account eligibility.

Final Thought

The error disappears as soon as Antigravity has a valid default project to call. Set the project id, clear stale state, then reauthenticate with a forced sync and your requests will resolve to projects with the correct id.