Merge pull request #1253 from github/jm/experimental

docs: add experimental mode section to README

Author: jmoseley

README.md

@@ -118,6 +118,19 @@ Launch `copilot` in a folder that contains code you want to work with.
 
 By default, `copilot` utilizes Claude Sonnet 4.5. Run the `/model` slash command to choose from other available models, including Claude Sonnet 4 and GPT-5.
 
+### Experimental Mode
+
+Experimental mode enables access to new features that are still in development. You can activate experimental mode by:
+
+- Launching with the `--experimental` flag: `copilot --experimental`
+- Using the `/experimental` slash command from within the CLI
+
+Once activated, the setting is persisted in your config, so the `--experimental` flag is no longer needed on subsequent launches.
+
+#### Experimental Features
+
+- **Autopilot mode:** Autopilot is a new mode (press `Shift+Tab` to cycle through modes), which encourages the agent to continue working until a task is completed.
+
 Each time you submit a prompt to GitHub Copilot CLI, your monthly quota of premium requests is reduced by one. For information about premium requests, see [About premium requests](https://docs.github.com/copilot/managing-copilot/monitoring-usage-and-entitlements/about-premium-requests).
 
 For more information about how to use the GitHub Copilot CLI, see [our official documentation](https://docs.github.com/copilot/concepts/agents/about-copilot-cli).