Gemini CLI Misrepresents Billing Model to Users, resulting in catastrophic billing (4'000 $ in 2 days)

### What happened?

A prompt with Gemini CLI on how to set up the Gemini API to allow a third app only results into catastrophic billing (4'000$ USD in two days), due to Gemini CLI explicitly telling the user that it uses "Google's internal quota" and is "not connected to your personal API key or your AI Studio projects."

This is false. The CLI silently charges users' projects with gemini-2.5-pro (the most expensive model) without warning or cost disclosure. The user can continue working without noticing anything, and be billed extremely high rates (4000$ for two days). The problem is aggravated by problems with Google Billing does sends alerts (seeing a 8'000% increase in usage) two days after the trigger.

Inspection of the Gemini prompt shows that Gemini CLI's understanding of the Gemini's API is poor, with a large number of errors throughout the process. Even user's prompts such as (see attached, full promtp available on request)

[@session-2026-05-11T14-20-42829064_EXTRACT.md](https://github.com/user-attachments/files/28611601/%40session-2026-05-11T14-20-42829064_EXTRACT.md)

:

> "but how can I control the API usage? is there a way to ensure I won't pay anything, i.e. the API blocks if I go over the free limit?".

result in Gemini's CLI giving misleading claims to the user.

### What did you expect to happen?

## Evidence

**CLI's exact statement to user (May 11, 15:34 UTC):**
> "Our interaction here in the Gemini CLI uses a separate, dedicated quota provided by Google... It is not connected to your personal API key or your AI Studio projects."

When users ask how to prevent charges, the CLI provides this false assurance.

**Actual behavior:** CLI charges the user's GCP project. A user was charged USD 4'000 in two days for normal usage.

## Impact

- Unexpected charges accumulate with no visibility
- Users cannot prevent charges (false assurance from CLI)
- Billing alerts fail to trigger in time (48-hour delay observed)

### Client information

Client Information

Run `gemini` to enter the interactive CLI, then run the `/about` command.

```console
> /about
About Gemini CLI │
│ │
│ CLI Version 0.45.0 │
│ Git Commit 0a11ce3e9 │
│ Model gemini-3-flash-preview │
│ Sandbox no sandbox │
│ OS linux │
│ Auth Method Signed in with Google │
│ (matthieu.stigler@gmail.com) │
│ Tier Gemini Code Assist for individuals │
│
```

### Login information

### Anything else we need to know?

This issue will likely require coordination with Google Cloud Billing to inform their services about the potentially catastrophic billing consequences of gemini CLI.

## Related Issues

This is related, but not a duplicate, of : #4472, #21180, #6495, #4861

Given the catastrophic billing consequences and compounding failures on the Google Cloud side (alerts delayed 48+ hours, support unresponsiveness), this issue warrants critical priority.