olb: Oraios Language Backends (beta)

olb installs Oraios language backends and runs them for your projects. A language backend is an IDE (currently the Oraios IDE for Java, Kotlin and Groovy) that runs invisibly in the background and gives Serena IDE-grade code understanding and refactoring for your projects.

Beta test notes:

• Windows and Linux (x64). On Linux, see the extra requirement below.
• The test builds of the language backend stop working on 2026-11-01.
• Disk space: about 1.5 GB for the installed language backend, plus the IDE's indexes per project.

1. Install olb

Requires uv.

uv tool install olb-cli
olb --version

If olb is not found afterwards, run uv tool update-shell and open a new terminal. To update later: uv tool upgrade olb-cli.

On Linux, the IDE runs on an invisible virtual display, which requires one of these (Ubuntu/Debian commands):

• TigerVNC (lightweight): sudo apt-get install tigervnc-standalone-server tigervnc-viewer
• Xpra (shows the IDE as regular windows, but a considerably larger installation): sudo apt-get install xpra

If both are installed, Xpra is used.

2. Install the JVM language backend

olb install jvm

• This downloads and installs the Oraios IDE (about 830 MB) and everything it needs.
• olb list shows what is installed; olb available shows the available language backends.
• Everything is stored in %LOCALAPPDATA%\Oraios\olb. To use a different location (e.g. another drive), set the environment variable OLB_HOME to a directory of your choice before installing.

3. Configure Serena to use the backend

The olb-jvm backend requires a version of Serena that includes it. For the beta, install Serena from its GitHub repository:

uv tool install -p 3.13 --force "git+https://github.com/oraios/serena@olb-jvm"

Then select the backend in one of these ways:

• For all projects: in Serena's global configuration (~/.serena/serena_config.yml, also reachable via serena config edit), set

  language_backend: olb-jvm
  

• For a single project: set the same key in the project's .serena/project.yml.
• Per MCP server: add --language-backend olb-jvm to the serena start-mcp-server command in your client's MCP configuration.

When Serena activates a project, it starts the language backend's IDE for it automatically (invisibly, one IDE per project). The first activation of a project takes a little longer, as the IDE indexes the project.

Looking at the IDE (e.g. to fix the project configuration)

If Serena's results suggest that the project is not set up correctly in the IDE (e.g. a missing JDK, or a Maven/Gradle project that was not imported), you can look at the running IDE and fix it there:

olb show

• Run it in your project's directory, or when only one IDE is running. Otherwise, olb show lists the running IDEs with a number each; pick one with olb show <number> (or olb show <project-dir>).
• Windows: this switches your screen to the IDE. Use the "Back to your desktop" button in the bottom-right corner (or olb hide) to return. Ctrl+Alt+Del always brings you back, too. If you minimize the IDE window there, the "Restore IDE window" button brings it back (as does the next olb show).
• Linux with Xpra: the IDE appears as a regular window on your desktop. Closing it (or olb hide) only hides it; the IDE keeps running in the background.
• Linux with TigerVNC: a VNC viewer window shows the IDE. Closing the viewer (or olb hide) hides it again.
• Settings you change there apply to that project only.

Other commands

• olb status: the running IDEs with their numbers, whether they are starting or serving, and where their logs are.
• olb stop: stops an IDE, selected like for olb show (Serena restarts it when needed).
• olb uninstall jvm: removes the language backend.
• olb --help and olb <command> --help for details.

Reporting problems

Please include the output of olb status and the IDE's log files (idea.log, supervisor.log) from the log directory it shows.