Add cmake consumption skill

Author: zayenz

README.md

@@ -23,6 +23,7 @@ npx skills add Gecode/gecode-skills --skill gecode-modeling
 ## Available Skills
 
 - `gecode-general-knowledge`
+- `gecode-cmake-consumption`
 - `gecode-modeling`
 - `gecode-propagator-implementation`
 - `gecode-brancher-implementation`

skills/gecode-cmake-consumption/SKILL.md

@@ -0,0 +1,47 @@
+---
+name: gecode-cmake-consumption
+description: "Consume Gecode from CMake using exported package config (`find_package(Gecode CONFIG)`), aggregate/component targets, version checks, and source-fetch fallback patterns. Use when integrating Gecode into downstream CMake projects or migrating custom `FindGecode.cmake` logic. Assume Gecode 6.3.0 or newer."
+---
+
+# Gecode CMake Consumption
+
+## Core
+- Prefer config-package consumption: `find_package(Gecode CONFIG REQUIRED)`.
+- Link downstream targets to `Gecode::gecode` unless explicit component granularity is required.
+- Require `Gecode_VERSION >= 6.3.0`; use package version checks rather than parsing `gecode/support/config.hpp`.
+- Hint package location with `Gecode_ROOT` or `CMAKE_PREFIX_PATH`.
+- Keep `cmake_minimum_required(VERSION 3.21)` or newer for parity with Gecode's build.
+
+## Canonical Patterns
+- Minimal integration:
+  ```cmake
+  find_package(Gecode CONFIG REQUIRED)
+  target_link_libraries(app PRIVATE Gecode::gecode)
+  ```
+- Component-specific integration:
+  ```cmake
+  find_package(Gecode CONFIG REQUIRED COMPONENTS driver)
+  target_link_libraries(app PRIVATE Gecode::gecodedriver)
+  ```
+- Version guard:
+  ```cmake
+  if(SOME_STRICT_OPTION AND Gecode_VERSION VERSION_LESS "6.3.0")
+    message(FATAL_ERROR "Gecode >= 6.3.0 required, found ${Gecode_VERSION}")
+  endif()
+  ```
+
+## Dependency Resolution Workflow
+- Try installed package first via `find_package(Gecode CONFIG QUIET)` when optional discovery is desired.
+- If not found and project policy allows vendoring, use `FetchContent` to obtain Gecode source and call `FetchContent_MakeAvailable(...)`.
+- Set Gecode cache options before `FetchContent_MakeAvailable(...)` to limit dependency surface (for example disable `GECODE_ENABLE_GIST`, examples, tests, or optional modules).
+- Require `TARGET Gecode::gecode` after resolution; fail fast with actionable error text if absent.
+- Mark Gecode target as `SYSTEM` in strict-warning projects to isolate third-party headers from local warning policy.
+- For source-pinned fallback builds, prefer stable release tags or commits over long-lived feature branches.
+- For migration away from custom discovery modules, remove manual imported-target composition and library probing once package config is the baseline path.
+- Keep strict-version toggles if desired, but enforce them against `Gecode_VERSION`.
+
+## Pitfalls
+- Calling `find_package(Gecode REQUIRED)` without `CONFIG` and accidentally resolving old/module-mode shims.
+- Assuming optional components exist without checking enabled modules in the installed build.
+- Mixing custom imported-target composition with package-provided targets in the same code path.
+- Parsing headers for version when package metadata already provides `Gecode_VERSION`.

skills/gecode-cmake-consumption/agents/openai.yaml

@@ -0,0 +1,4 @@
+interface:
+  display_name: "Gecode CMake Consumption"
+  short_description: "Integrate Gecode via CMake package config"
+  default_prompt: "Guide downstream CMake integration with Gecode package exports, version checks (>= 6.3.0), and migration from custom FindGecode logic."

skills/gecode-general-knowledge/SKILL.md

@@ -6,6 +6,7 @@ description: "Core Gecode architecture and runtime model: spaces, propagators, b
 # Gecode General Knowledge
 
 ## Related Skills
+- Use `gecode-cmake-consumption` for downstream CMake integration, package consumption, and migration from custom `FindGecode` logic.
 - Use `gecode-modeling` for modeling choices, globals, branchings, symmetry handling, and search setup.
 - Use `gecode-propagator-implementation` for custom propagator design, posting, propagation lifecycle, and optimization.
 - Use `gecode-brancher-implementation` for custom branchers, choice/commit mechanics, and no-good literal support.