The language server uses a compile_commands.json file to understand how each translation unit in your project is built. Generate this file with your build system, then follow the configuration guide to point the language server at it or use automatic discovery.
For CMake or MSBuild (vcxproj) projects, run the generate-compile-commands skill in GitHub Copilot CLI with a prompt like "regenerate compile commands" or "load project" to generate the file and configure the language server. The skill is included with the cpp-language-server plugin.
If you don't want to use the skill, follow the build-system guidance below.
CMake projects that use the Ninja or Makefile generators can easily create a compile_commands.json by setting the CMAKE_EXPORT_COMPILE_COMMANDS variable during configuration. For CMake projects that typically use other generators, first check if it is possible as a one-off to configure the project using the Ninja or Makefile generator, as this is the easiest way to get compile_commands.json.
Add -DCMAKE_EXPORT_COMPILE_COMMANDS=ON to your CMake configuration command.
For AI assistance with this step, try adding this skill to GitHub Copilot CLI and running it. Learn more about skills with the GitHub Copilot CLI documentation.
Improved support for MSBuild projects is planned for a future release of the Microsoft C++ Language Server.
For now, refer to this sample application for an example of how to generate compile_commands.json from MSBuild projects. While the sample application is designed to work out-of-the-box for many projects, it may require adaptation for complex projects.
Refer to your build system vendor's documentation.
For custom or non-standard builds, we recommend capturing the steps to generate compile_commands.json in a project-specific skill so the process is reproducible for you and your team. Once you've worked out the commands needed to produce the file, save them as a skill (for example, in your project's skills/ directory) following the GitHub Copilot CLI skills documentation. The setup-cpp-language-server skill is a good starting template to adapt.
For guidance on authoring a project-specific skill, see authoring an extractor skill.