Modern C++ Project Setup

Overview

Create or modernize a C++ project around a reproducible toolchain:

Git -> GitHub -> VS Code -> CMakePresets + vcpkg -> Ninja -> compiler -> tests/lint/docs

Prefer project-local, repeatable setup over global machine assumptions. First classify the user's working directory and host platform, then either generate a greenfield scaffold or patch the existing project without erasing its current pipeline.

Workflow

1. Determine the user's working directory and whether a project already exists.

   • Check the user-provided path or current working directory before writing files.
   • Treat the directory as an existing project if it already has source files, CMakeLists.txt, build scripts, package metadata, editor config, CI, docs, or a git history.
   • For existing work, inventory the full development pipeline before editing: build system, dependency manager, compiler and standard, presets/tasks/scripts, tests, format/lint/static analysis, docs, debugger/editor integration, CI, packaging/install rules, and generated artifacts.
   • For greenfield work, default to an app plus reusable library target, C++20, Ninja, vcpkg manifest mode, GoogleTest, clang-format, clang-tidy, Doxygen, and VS Code settings.
   • If the request is about MCU firmware, OpenOCD, linker scripts, startup code, arm-none-eabi, or Cortex-Debug, switch to embedded-project-setup.

2. Detect the user's host development environment.

   • Determine OS and architecture: macOS/Linux/Windows plus arm64 or x64. Use local commands such as uname -s, uname -m, sysctl -n machdep.cpu.brand_string, or PowerShell/.NET runtime information where appropriate.
   • Select a host profile: macos-arm64, macos-x64, linux-x64, linux-arm64, windows-x64, or windows-arm64.
   • If the agent is running somewhere other than the user's real development machine, ask for the user's OS/architecture instead of assuming the sandbox matches their workstation.

3. Generate or update the project.

   • For greenfield scaffolding, run from this skill directory:

python3 scripts/scaffold_cpp_project.py \
  --name my_app \
  --out /path/to/workspace/my_app \
  --host-platform macos-arm64

• The scaffold script renders reusable standard configuration from assets/ for CMake, CMake presets, vcpkg, and VS Code. Update those assets when the shared project standard changes; update the Python script when generation logic, arguments, or dynamic source files change.
• For existing projects, use references/cpp-project-blueprint.md as a checklist and adapt to the repository's current style instead of replacing unrelated files.
• Omit --host-platform only when generating on the same machine where the project will be developed; the script will auto-detect that host.

4. Keep the toolchain contract explicit.

   • Use CMakePresets.json for configure/build profiles.
   • Use vcpkg manifest mode through vcpkg.json.
   • Use host-specific vcpkg triplets such as arm64-osx, x64-osx, x64-linux, arm64-linux, x64-windows, and arm64-windows.
   • Use Ninja as the generator unless the user or platform requires otherwise.
   • Use Clang on macOS, GCC on Linux, and MSVC on Windows by default.

5. Wire editor support.

   • Recommend VS Code extensions: CMake Tools, clangd, CodeLLDB for macOS/Linux, and Microsoft C/C++ debugging support for Windows.
   • Disable competing IntelliSense when clangd is responsible for semantic analysis.
   • Make compile_commands.json available through CMake configure output and point clangd at the active preset's build directory.
   • Add launch configurations for the generated executable on macOS/Linux and Windows when creating a cross-platform scaffold.

6. Add quality gates.

   • Add GoogleTest tests with ctest.
   • Add .clang-format and .clang-tidy.
   • Add a Doxygen configuration path, but do not require docs generation for a normal build.
   • Add CI only when requested or when the project setup task includes GitHub/GitHub Actions.

Validation

Run the strongest available validation for the target machine:

cmake --list-presets
bash scripts/bootstrap_vcpkg.sh
cmake --preset macos-arm64-debug
cmake --build --preset macos-arm64-debug
ctest --test-dir build/macos-arm64-debug --output-on-failure
bash scripts/format.sh --check
cmake --preset macos-arm64-tidy
cmake --build --preset macos-arm64-tidy
cmake --build --preset macos-arm64-debug --target docs

Adjust preset names for the selected host profile. On Windows, use pwsh scripts/bootstrap_vcpkg.ps1 and pwsh scripts/format.ps1 -Check. If vcpkg, compilers, or Doxygen are unavailable, report exactly what was skipped and why.

References

• Read references/cpp-project-blueprint.md when choosing project layout, presets, dependency policy, editor settings, tests, formatting, linting, docs, or CI details.
• Read the scaffold script before changing its generated files or adding new options.
• Read assets/ before changing standard generated configuration files; treat those files as templates and keep project-specific values behind @PLACEHOLDER@ variables.