Nimblio extensions

Nimblio ships with actions for files, apps, websites, text and Windows. Extensions add more: “Play or pause in Spotify”, “Post to a Discord channel”, “Set my keyboard lighting”. Each one is a .nbext file that people install from Nimblio. You write it in C# with the Nimblio SDK, and debug it live in Nimblio from VS Code.

What an extension adds

An extension adds actions. They sit in the action library next to the built-in ones and behave like them:

• Settings in the inspector: text, folders, choices, switches, sliders, and fields that accept values from earlier steps.
• A one-line summary on the step card, such as “Turn the volume Up by 5”.
• A value for later steps, such as Track name, or a list to repeat over.
• Errors that say what happened and how to fix it, in the run’s error panel.
• Lines in Run history, notifications, questions to the person, the clipboard and stored secrets.

Extensions can’t add new ways to start a workflow yet.

How extensions run

• In their own process. Each extension runs in a separate Nimblio.ExtensionHost.exe. If it crashes or hangs, only the step that was running fails, and the next run starts it again. It starts when one of its actions first runs and stops after 5 idle minutes.
• Described up front. The file extension.json lists every action and setting. Nimblio shows them in the library, the inspector and the MCP server without running any of your code.
• Safe for workflows. Steps are saved as ext:<extension id>/<action id>. If someone opens a workflow without the extension, the steps stay and say which extension to install. Exported workflows list the extensions they need.
• Not a sandbox. People see the permissions you ask for before they install. Nimblio enforces them for what it provides (clipboard, notifications), but your .NET code runs with the person’s Windows rights. Ask only for what you use, and say what you do with it.

Installing an extension

This is what people who use your extension do, so it helps to know it:

1. Open Downloads. Click the download icon at the right of the title bar, next to search, thenImport… and pick the .nbext file. Double-clicking the file in Explorer, or dragging it onto the Nimblio window, does the same.
2. Read the install dialog. It shows the publisher, the version, what the extension can do (its permissions), the actions it adds, and a warning that the file isn’t signed.
3. Install. The actions appear in the action library right away, under the extension’s own category.

In Downloads, each extension has a switch to turn it off and a … menu with Details, Open folder, Open log and Uninstall. Uninstalling keeps the extension’s data folder, so reinstalling it later keeps its settings and secrets.

Where to go next