> For the complete documentation index, see [llms.txt](https://docs.urbit.org/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.urbit.org/build-on-urbit/userspace.md). # Userspace Guides for building and distributing userspace applications on Urbit, including examples, exercises, and tutorials for app development. Gall is one of the ten vanes (kernel modules) of Arvo, Urbit's operating system. Gall's purpose is to manage userspace applications called *agents*. **Agents** are the main kind of userspace application on Urbit. They have a persistent state and API that handles events and produces effects.Gall agents can variously be treated as databases with developer-defined logic, services, daemons, or a kind of state machine. One or more Gall agents can be put together in a "desk" in Clay (the filesystem vane) and, along with a front-end, can be published and distributed as a cohesive app for users to install. This section of the docs contains guides related to writing apps and [distributing them](/build-on-urbit/userspace/dist/software-distribution.md). It also contains a number of different [examples and exercises](/build-on-urbit/userspace/examples.md) you can work through to learn how to build different kinds of apps. Additionally, the [courses](/build-on-urbit/contents.md) section of the docs contain two in-depth app-building tutorials, which are the recommended place to start learning Urbit app development: * [App School](/build-on-urbit/app-school.md) - Learn the basics of app development. * [App School II](/build-on-urbit/app-school-full-stack.md) - Learn to build and publish a full app, back-end and front-end. --- # Agent Instructions This documentation is published with GitBook. GitBook is the documentation platform designed so that both humans and AI agents can read, navigate, and reason over technical content effectively. Learn more at gitbook.com. ## Querying This Documentation If you need additional information that is not directly available in this page, you can query the documentation by asking a question. Perform an HTTP GET request on the following URL with the `ask` and `goal` query parameters: ``` GET https://docs.urbit.org/build-on-urbit/userspace.md?ask=&goal= ``` `ask` is the immediate question: it should be specific, self-contained, and written in natural language. `goal` is what the user is ultimately trying to achieve, the reason they need the answer. Sharing it helps GitBook give you a better, more relevant answer. A goal is most helpful when it describes the outcome the user wants rather than restating the question. For example, with `ask=how do I create an API token`, a goal like `automate deployments from our CI pipeline` lets GitBook tailor the answer to that use case. The response will contain a direct answer to the question and relevant excerpts and sources from the documentation. Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.