gemini-cli/docs/troubleshooting.md

# Troubleshooting guide

This guide provides solutions to common issues and debugging tips, including topics on:

- Authentication or login errors
- Frequently asked questions (FAQs)
- Debugging tips
- Existing GitHub Issues similar to yours or creating new Issues

## Authentication or login errors

- **Error: `Failed to login. Message: Request contains an invalid argument`**
  - Users with Google Workspace accounts or Google Cloud accounts
    associated with their Gmail accounts may not be able to activate the free
    tier of the Google Code Assist plan.
  - For Google Cloud accounts, you can work around this by setting
    `GOOGLE_CLOUD_PROJECT` to your project ID.
  - Alternatively, you can obtain the Gemini API key from
    [Google AI Studio](http://aistudio.google.com/app/apikey), which also includes a
    separate free tier.

- **Error: `UNABLE_TO_GET_ISSUER_CERT_LOCALLY` or `unable to get local issuer certificate`**
  - **Cause:** You may be on a corporate network with a firewall that intercepts and inspects SSL/TLS traffic. This often requires a custom root CA certificate to be trusted by Node.js.
  - **Solution:** Set the `NODE_EXTRA_CA_CERTS` environment variable to the absolute path of your corporate root CA certificate file.
    - Example: `export NODE_EXTRA_CA_CERTS=/path/to/your/corporate-ca.crt`

## Common error messages and solutions

- **Error: `EADDRINUSE` (Address already in use) when starting an MCP server.**
  - **Cause:** Another process is already using the port that the MCP server is trying to bind to.
  - **Solution:**
    Either stop the other process that is using the port or configure the MCP server to use a different port.

- **Error: Command not found (when attempting to run Gemini CLI with `gemini`).**
  - **Cause:** Gemini CLI is not correctly installed or it is not in your system's `PATH`.
  - **Solution:**
    The update depends on how you installed Gemini CLI:
    - If you installed `gemini` globally, check that your `npm` global binary directory is in your `PATH`. You can update Gemini CLI using the command `npm install -g @google/gemini-cli@latest`.
    - If you are running `gemini` from source, ensure you are using the correct command to invoke it (e.g., `node packages/cli/dist/index.js ...`). To update Gemini CLI, pull the latest changes from the repository, and then rebuild using the command `npm run build`.

- **Error: `MODULE_NOT_FOUND` or import errors.**
  - **Cause:** Dependencies are not installed correctly, or the project hasn't been built.
  - **Solution:**
    1.  Run `npm install` to ensure all dependencies are present.
    2.  Run `npm run build` to compile the project.
    3.  Verify that the build completed successfully with `npm run start`.

- **Error: "Operation not permitted", "Permission denied", or similar.**
  - **Cause:** When sandboxing is enabled, Gemini CLI may attempt operations that are restricted by your sandbox configuration, such as writing outside the project directory or system temp directory.
  - **Solution:** Refer to the [Configuration: Sandboxing](./cli/sandbox.md) documentation for more information, including how to customize your sandbox configuration.

- **Gemini CLI is not running in interactive mode in "CI" environments**
  - **Issue:** The Gemini CLI does not enter interactive mode (no prompt appears) if an environment variable starting with `CI_` (e.g., `CI_TOKEN`) is set. This is because the `is-in-ci` package, used by the underlying UI framework, detects these variables and assumes a non-interactive CI environment.
  - **Cause:** The `is-in-ci` package checks for the presence of `CI`, `CONTINUOUS_INTEGRATION`, or any environment variable with a `CI_` prefix. When any of these are found, it signals that the environment is non-interactive, which prevents the Gemini CLI from starting in its interactive mode.
  - **Solution:** If the `CI_` prefixed variable is not needed for the CLI to function, you can temporarily unset it for the command. e.g., `env -u CI_TOKEN gemini`

- **DEBUG mode not working from project .env file**
  - **Issue:** Setting `DEBUG=true` in a project's `.env` file doesn't enable debug mode for gemini-cli.
  - **Cause:** The `DEBUG` and `DEBUG_MODE` variables are automatically excluded from project `.env` files to prevent interference with gemini-cli behavior.
  - **Solution:** Use a `.gemini/.env` file instead, or configure the `advanced.excludedEnvVars` setting in your `settings.json` to exclude fewer variables.

## Exit Codes

The Gemini CLI uses specific exit codes to indicate the reason for termination. This is especially useful for scripting and automation.

| Exit Code | Error Type                 | Description                                                                                         |
| --------- | -------------------------- | --------------------------------------------------------------------------------------------------- |
| 41        | `FatalAuthenticationError` | An error occurred during the authentication process.                                                |
| 42        | `FatalInputError`          | Invalid or missing input was provided to the CLI. (non-interactive mode only)                       |
| 44        | `FatalSandboxError`        | An error occurred with the sandboxing environment (e.g., Docker, Podman, or Seatbelt).              |
| 52        | `FatalConfigError`         | A configuration file (`settings.json`) is invalid or contains errors.                               |
| 53        | `FatalTurnLimitedError`    | The maximum number of conversational turns for the session was reached. (non-interactive mode only) |

## Debugging Tips

- **CLI debugging:**
  - Use the `--verbose` flag (if available) with CLI commands for more detailed output.
  - Check the CLI logs, often found in a user-specific configuration or cache directory.

- **Core debugging:**
  - Check the server console output for error messages or stack traces.
  - Increase log verbosity if configurable.
  - Use Node.js debugging tools (e.g., `node --inspect`) if you need to step through server-side code.

- **Tool issues:**
  - If a specific tool is failing, try to isolate the issue by running the simplest possible version of the command or operation the tool performs.
  - For `run_shell_command`, check that the command works directly in your shell first.
  - For _file system tools_, verify that paths are correct and check the permissions.

- **Pre-flight checks:**
  - Always run `npm run preflight` before committing code. This can catch many common issues related to formatting, linting, and type errors.

## Existing GitHub Issues similar to yours or creating new Issues

If you encounter an issue that was not covered here in this _Troubleshooting guide_, consider searching the Gemini CLI [Issue tracker on GitHub](https://github.com/google-gemini/gemini-cli/issues). If you can't find an issue similar to yours, consider creating a new GitHub Issue with a detailed description. Pull requests are also welcome!