diff --git a/.github/workflows/iwyu.yml b/.github/workflows/iwyu.yml
new file mode 100644
index 0000000..7f34c2d
--- /dev/null
+++ b/.github/workflows/iwyu.yml
@@ -0,0 +1,47 @@
+name: IWYU
+
+on:
+  workflow_call:  # Can also run on PRs by changing this to 'pull_request'
+  pull_request: 
+jobs:
+  Analyzers:
+    name: Check headers (IWYU)
+    runs-on: ubuntu-latest
+    defaults:
+      run:
+        working-directory: ${{ github.workspace }}
+        shell: bash
+    steps:
+      - name: Checkout repository
+        uses: actions/checkout@v4
+
+      - name: Install dependencies
+        run: |
+          sudo apt update
+          sudo apt install -y cmake ninja-build clang-17 libc++-17-dev libclang-17-dev wget
+
+      - name: Checkout IWYU
+        uses: actions/checkout@v4
+        with:
+          repository: include-what-you-use/include-what-you-use
+          ref: f25caa280dc3277c4086ec345ad279a2463fea0f
+          path: include-what-you-use
+          persist-credentials: false
+
+      - name: Build IWYU
+        run: |
+          mkdir -p build_iwyu && cd build_iwyu
+          cmake -G "Ninja" -DCMAKE_PREFIX_PATH="/usr/lib/llvm-17" ../include-what-you-use
+          ninja
+          sudo ninja install
+
+      - name: Check IWYU version
+        run: include-what-you-use --version
+
+      - name: Run IWYU analysis
+        run: |
+          # Generate compile_commands.json for your library
+          cmake -B build_iwyu_analysis -DCMAKE_EXPORT_COMPILE_COMMANDS=ON -DCMAKE_CXX_COMPILER=clang++ -DCMAKE_C_COMPILER=clang -S .
+          
+          # Run IWYU on all source files
+          iwyu_tool.py -p build_iwyu_analysis -- -Xiwyu --mapping="${{ github.workspace }}/.github/ci/libcxx17.imp" -Xiwyu --error
diff --git a/.github/workflows/test.yml b/.github/workflows/test.yml
index 4e1a665..9c8cc1d 100644
--- a/.github/workflows/test.yml
+++ b/.github/workflows/test.yml
@@ -5,8 +5,33 @@ on:
     branches: [ "main" ]
 
 jobs:
+  determine_changes:
+    name: Determine if functional changes exist
+    runs-on: ubuntu-latest
+    outputs:
+      skip_full_tests: ${{ steps.check.outputs.skip_full_tests }}
+    steps:
+      - uses: actions/checkout@v4
+      - id: check
+        run: |
+          # Check if PR body contains "no functional change"
+          if echo "${{ github.event.pull_request.body }}" | grep -iq "no functional changes"; then
+            echo "skip_full_tests=true" >> $GITHUB_OUTPUT
+            exit 0
+          fi
+          # List changed files between PR base and head
+          CHANGED=$(git diff --name-only ${{ github.event.before }} ${{ github.sha }})
+
+          # Check if any .cpp or .c files changed
+          if echo "$CHANGED" | grep -E '\.(cpp|c)$' >/dev/null; then
+            echo "skip_full_tests=false" >> "$GITHUB_OUTPUT"
+          else
+            echo "skip_full_tests=true" >> "$GITHUB_OUTPUT"
+          fi
+
   build:
-    if: ${{ !endsWith(github.event.pull_request.title, 'no functional change') }}
+    needs: determine_changes
+    if: ${{ needs.determine_changes.outputs.skip_full_tests != 'true' }}
     runs-on: ${{ matrix.os }}
 
     strategy:
@@ -52,7 +77,7 @@ jobs:
         shell: bash
         run: |
           if [[ "${{ matrix.os }}" == "ubuntu-latest" ]]; then
-            if "${{ matrix.cpp_compiler }}" == "clang++" ]]; then
+            if [[ "${{ matrix.cpp_compiler }}" == "clang++" ]]; then
               SANITIZERS="memory,undefined"
             else
               SANITIZERS="address,undefined"
diff --git a/.github/workflows/try_compile.yml b/.github/workflows/try_compile.yml
index e436057..a1759f3 100644
--- a/.github/workflows/try_compile.yml
+++ b/.github/workflows/try_compile.yml
@@ -2,7 +2,7 @@ name: Compilation
 
 on:
   push: 
-
+    branches-ignore: main
 jobs:
   build:
     runs-on: ${{ matrix.os }}
diff --git a/attacks.cpp b/attacks.cpp
index 69d0efc..899f960 100644
--- a/attacks.cpp
+++ b/attacks.cpp
@@ -1,5 +1,8 @@
 #include "attacks.h"
-
+#include "bitboard.h"
+#include <cstddef>
+#include <initializer_list>
+#include <utility>
 namespace chess::_chess {
 // [INTERNAL]
 
@@ -190,4 +193,4 @@ inline static std::array<std::array<Bitboard, SQ_NONE + 1>, SQ_NONE + 1> generat
     return squares_between_bb;
 }
 std::array<std::array<Bitboard, SQ_NONE + 1>, SQ_NONE + 1> SQUARES_BETWEEN_BB = generate_between();
-} // namespace chess::movegen
\ No newline at end of file
+} // namespace chess::movegen
diff --git a/attacks.h b/attacks.h
index 5027d84..08d4b22 100644
--- a/attacks.h
+++ b/attacks.h
@@ -1,6 +1,4 @@
 #pragma once
-#include "bitboard.h"
-#include "fwd_decl.h"
 #include "types.h"
 #include <array>
 #include <immintrin.h>
diff --git a/moves_io.cpp b/moves_io.cpp
index 06a89fe..6d613da 100644
--- a/moves_io.cpp
+++ b/moves_io.cpp
@@ -1,11 +1,11 @@
 #include "moves_io.h"
+#include "attacks.h"
 #include "position.h"
 #include "types.h"
 #include <algorithm>
-#include <iostream>
-#include <regex>
+#include <cassert>
+#include <cctype>
 #include <string_view>
-#if defined(__EXCEPTIONS)
 #define THROW_IF_EXCEPTIONS_ON(stuff) throw stuff
 #else
 #define THROW_IF_EXCEPTIONS_ON(stuff) ((void)0)
diff --git a/moves_io.h b/moves_io.h
index 5dccb74..b94cda1 100644
--- a/moves_io.h
+++ b/moves_io.h
@@ -1,9 +1,11 @@
 #pragma once
-#include "fwd_decl.h"
-#include <cstdint>
-#include <stdexcept>
+#include "types.h"
+#include <exception>
 #include <string>
 #include <string_view>
+namespace chess {
+template <typename T, typename> class _Position;
+}
 namespace chess::uci {
 std::string moveToUci(Move move, bool chess960 = false);
 
diff --git a/position.cpp b/position.cpp
index fb0b5b7..b35fe13 100644
--- a/position.cpp
+++ b/position.cpp
@@ -4,6 +4,7 @@
 #include "printers.h"
 #include "zobrist.h"
 #include <algorithm>
+#include <initializer_list>
 #include <iostream>
 #include <sstream>
 #include <utility>
diff --git a/position.h b/position.h
index 178e886..e7113a2 100644
--- a/position.h
+++ b/position.h
@@ -1,11 +1,17 @@
 #pragma once
 #include "attacks.h"
 #include "bitboard.h"
+#include "fwd_decl.h"
 #include "movegen.h"
 #include "types.h"
 #include "zobrist.h"
+#include <algorithm>
+#include <array>
+#include <cassert>
+#include <cstdint>
 #include <stdexcept>
 #include <string>
+#include <type_traits>
 #include <vector>
 namespace chess {
 
diff --git a/printers.cpp b/printers.cpp
index 74e69cc..f13315b 100644
--- a/printers.cpp
+++ b/printers.cpp
@@ -2,8 +2,10 @@
 #include "moves_io.h"
 #include "position.h"
 #include <algorithm>
+#include <cctype>
 #include <iomanip>
 #include <iostream>
+#include <string>
 #include <unordered_map>
 namespace chess {
 template <typename T> using DescriptiveNameNotation = std::unordered_map<T, std::string>;
@@ -146,4 +148,4 @@ template <typename PieceC, typename> std::ostream &operator<<(std::ostream &os,
 INSTANTITATE(EnginePiece)
 INSTANTITATE(PolyglotPiece)
 INSTANTITATE(ContiguousMappingPiece)
-} // namespace chess
\ No newline at end of file
+} // namespace chess
diff --git a/printers.h b/printers.h
index 42581c0..96bec90 100644
--- a/printers.h
+++ b/printers.h
@@ -1,6 +1,5 @@
 #pragma once
-#include "fwd_decl.h"
-#include <cstdint>
+#include "types.h"
 #include <iosfwd>
 #include <type_traits>
 namespace chess {
@@ -16,4 +15,4 @@ template <typename T, typename> class _Position;
 
 template <typename PieceC = EnginePiece, typename = std::enable_if_t<is_piece_enum<PieceC>::value>>
 std::ostream &operator<<(std::ostream &os, const _Position<PieceC, void> &pos);
-} // namespace chess
\ No newline at end of file
+} // namespace chess