September 23, 2026
C++ project search in Copilot CLI got faster: the index stores all code
On September 22, 2026, Copilot CLI gained a persistent index of a C++ project. It includes symbols, types, and file relationships, even for files closed in the editor.
Previously, GitHub Copilot CLI could re-extract project information every time it navigated to a symbol definition or usage. Now whole codebase indexing reuses the index and speeds up code intelligence in C++ repositories with millions of lines.
Setup. Install the plugin with `/plugin install cpp-language-server@copilot-plugins`, then run `npx @microsoft/cpp-language-server --accept-eula --login`. WCI is enabled by default after setup, but it needs a valid `compile_commands.json`: for CMake and MSBuild, the `generate-compile-commands` skill offers to create one.
Run Copilot CLI from the project root, check the server with `/lsp show`, and view indexing progress and logs in `/lsp logs`. On first launch, the server builds or loads an index for the entire project, so startup may take more time and memory.
Microsoft C++ Language Server is still in preview. It requires an active GitHub Copilot subscription, Copilot CLI, and npm; Windows, macOS, and Linux are listed as supported. Copilot CLI is available on all Copilot plans, while Pro, Pro+, and Max cost $10, $39, and $100 per month.
Microsoft C++ Language Server remains in preview.
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