Gemini CLI Overloaded Error with API Key — Google Auth Works Fine

What this error means

Overloaded — Gemini API Key authentication returns overloaded error while Google Auth works is a Gemini API failure pattern reported for developers trying to fix gemini cli overloaded error when using api key while google account auth works normally. Based on the imported evidence, treat this as a tool-specific troubleshooting page rather than a generic API error.

Why this happens

Official GitHub issue from google-gemini/gemini-cli repo. Gemini CLI encounters overloaded errors specifically when using API key authentication, while Google account authentication works normally. Issue from official repo with detailed client information.

Common causes

• Gemini CLI frequently encounters overloaded errors when using an API key, but authentication via Google account works fine. This differential behavior confuses developers and creates strong search intent — they want to understand why one auth method works while the other fails. Affects paid API key users specifically.
• Official GitHub issue from google-gemini/gemini-cli repo. Gemini CLI encounters overloaded errors specifically when using API key authentication, while Google account authentication works normally. Issue from official repo with detailed client information.

Quick fixes

1. Confirm the exact error signature matches Overloaded — Gemini API Key authentication returns overloaded error while Google Auth works.
2. Check the Gemini API account, local tool state, and provider configuration involved in the failing workflow.
3. Verify the account session, API key, provider settings, and environment where the failing tool is running.

Platform/tool-specific checks

• Verify the command, editor, extension, or API client that produced the error.
• Compare local settings with CI, deployment, or editor-level settings when the error appears in only one environment.
• Avoid deleting credentials, local model data, or project settings until the failing scope is clear.

Step-by-step troubleshooting

1. Capture the exact error message and the command, editor action, or request that triggered it.
2. Check whether the failure is account/auth, quota/rate, model/provider, local runtime, or deployment configuration.
3. Review the source evidence below and compare it with your environment.
4. Apply one change at a time and rerun the smallest failing action.
5. Keep the working fix documented for the team or deployment environment.

How to prevent it

• Keep provider/tool configuration documented.
• Record non-secret diagnostics such as tool version, provider name, model name, and command path.
• Add a lightweight check before CI or production workflows depend on the tool.

Sources checked

• https://github.com/google-gemini/gemini-cli/issues/8548

Evidence note: Official GitHub issue from google-gemini/gemini-cli repo. Gemini CLI encounters overloaded errors specifically when using API key authentication, while Google account authentication works normally. Issue from official repo with detailed client information.

Related errors

• Gemini API key rate limit vs quota difference
• Gemini authentication method affects rate limits
• Google Cloud API key overloaded but OAuth works

FAQ

What should I check first?

Start with the exact Overloaded — Gemini API Key authentication returns overloaded error while Google Auth works text and the smallest action that reproduces it.

Can I ignore this error?

No. Treat it as a failed Gemini API workflow until the root cause is understood.

Is this guaranteed to have one fix?

No. The imported evidence supports the troubleshooting path above, but tool behavior can vary by account, plan, version, provider, and local configuration.

How do I know the fix worked?

Rerun the same command, editor action, or request. The fix is working when that action completes without Overloaded — Gemini API Key authentication returns overloaded error while Google Auth works.