diff --git a/.github/workflows/_build.yml b/.github/workflows/_build.yml
index 47b5b17b5e..04cf0406bb 100644
--- a/.github/workflows/_build.yml
+++ b/.github/workflows/_build.yml
@@ -41,7 +41,7 @@ jobs:
             goarch: arm64
             cc: gcc
             cxx: g++
-          - os: macos-14
+          - os: macos-15
             goos: darwin
             goarch: arm64
             cc: cc
diff --git a/.github/workflows/_memwaste.yml b/.github/workflows/_memwaste.yml
index 174490db6c..09deb0c37e 100644
--- a/.github/workflows/_memwaste.yml
+++ b/.github/workflows/_memwaste.yml
@@ -115,7 +115,7 @@ jobs:
 
   event-macos:
     if: ${{ inputs.mode == 'full' }}
-    runs-on: macos-14
+    runs-on: macos-15
     timeout-minutes: 60
     steps:
       - uses: actions/checkout@3d3c42e5aac5ba805825da76410c181273ba90b1 # v7.0.1
diff --git a/.github/workflows/_smoke.yml b/.github/workflows/_smoke.yml
index 1dd85e1be5..0242516180 100644
--- a/.github/workflows/_smoke.yml
+++ b/.github/workflows/_smoke.yml
@@ -33,7 +33,7 @@ jobs:
           CORE_UNIX='[
             {"os":"ubuntu-latest","goos":"linux","goarch":"amd64"},
             {"os":"ubuntu-24.04-arm","goos":"linux","goarch":"arm64"},
-            {"os":"macos-14","goos":"darwin","goarch":"arm64"},
+            {"os":"macos-15","goos":"darwin","goarch":"arm64"},
             {"os":"macos-15-intel","goos":"darwin","goarch":"amd64"}
           ]'
           # Broad legs reuse existing goos/goarch artifacts on additional OS
diff --git a/.github/workflows/_soak.yml b/.github/workflows/_soak.yml
index abf365f541..63c3ec51e7 100644
--- a/.github/workflows/_soak.yml
+++ b/.github/workflows/_soak.yml
@@ -44,7 +44,7 @@ jobs:
             goarch: arm64
             cc: gcc
             cxx: g++
-          - os: macos-14
+          - os: macos-15
             goos: darwin
             goarch: arm64
             cc: cc
@@ -335,7 +335,7 @@ jobs:
             goarch: arm64
             cc: gcc
             cxx: g++
-          - os: macos-14
+          - os: macos-15
             goos: darwin
             goarch: arm64
             cc: cc
diff --git a/.github/workflows/_test.yml b/.github/workflows/_test.yml
index 7ccd56bf5b..221eb34616 100644
--- a/.github/workflows/_test.yml
+++ b/.github/workflows/_test.yml
@@ -40,7 +40,7 @@ jobs:
           CORE_UNIX='[
             {"os":"ubuntu-latest","cc":"gcc","cxx":"g++"},
             {"os":"ubuntu-24.04-arm","cc":"gcc","cxx":"g++"},
-            {"os":"macos-14","cc":"cc","cxx":"c++"},
+            {"os":"macos-15","cc":"cc","cxx":"c++"},
             {"os":"macos-15-intel","cc":"cc","cxx":"c++"}
           ]'
           # Broad matrix legs are REQUIRED gates (no optional/continue-on-error
@@ -376,7 +376,7 @@ jobs:
         include:
           - { os: ubuntu-latest, cc: clang, cxx: clang++ }
           - { os: ubuntu-24.04-arm, cc: clang, cxx: clang++ }
-          - { os: macos-14, cc: cc, cxx: c++ }
+          - { os: macos-15, cc: cc, cxx: c++ }
     runs-on: ${{ matrix.os }}
     timeout-minutes: 120
     steps:
diff --git a/.github/workflows/bug-repro.yml b/.github/workflows/bug-repro.yml
index 2910606d03..e3e1a647a6 100644
--- a/.github/workflows/bug-repro.yml
+++ b/.github/workflows/bug-repro.yml
@@ -40,7 +40,7 @@ jobs:
             group: linux
             cc: gcc
             cxx: g++
-          - os: macos-14
+          - os: macos-15
             group: macos
             cc: cc
             cxx: c++
diff --git a/.github/workflows/cache-warm.yml b/.github/workflows/cache-warm.yml
index ff15fbb1a7..bca57b23b7 100644
--- a/.github/workflows/cache-warm.yml
+++ b/.github/workflows/cache-warm.yml
@@ -27,7 +27,7 @@ jobs:
         include:
           - { os: ubuntu-latest, cc: gcc, cxx: g++ }
           - { os: ubuntu-24.04-arm, cc: gcc, cxx: g++ }
-          - { os: macos-14, cc: cc, cxx: c++ }
+          - { os: macos-15, cc: cc, cxx: c++ }
           - { os: macos-15-intel, cc: cc, cxx: c++ }
     runs-on: ${{ matrix.os }}
     timeout-minutes: 60
diff --git a/.github/workflows/pr.yml b/.github/workflows/pr.yml
index 8cb464b190..7cdd20d092 100644
--- a/.github/workflows/pr.yml
+++ b/.github/workflows/pr.yml
@@ -105,7 +105,7 @@ jobs:
     strategy:
       fail-fast: false
       matrix:
-        os: [ubuntu-latest, macos-14, windows-latest]
+        os: [ubuntu-latest, macos-15, windows-latest]
     runs-on: ${{ matrix.os }}
     timeout-minutes: 30
     steps:
@@ -116,7 +116,7 @@ jobs:
         run: sudo apt-get update && sudo apt-get install -y zlib1g-dev ccache
 
       - name: Install ccache (macOS)
-        if: matrix.os == 'macos-14'
+        if: matrix.os == 'macos-15'
         run: command -v ccache >/dev/null 2>&1 || brew install ccache
 
       - uses: msys2/setup-msys2@66cd2cce69caa17b53920067426061ca1de3a884 # v2
@@ -155,7 +155,7 @@ jobs:
           CCACHE_MAXSIZE: 1000M
 
       - name: Build prod + smoke (macOS)
-        if: matrix.os == 'macos-14'
+        if: matrix.os == 'macos-15'
         run: |
           scripts/build.sh CC=cc CXX=c++
           codesign --sign - --force build/c/codebase-memory-mcp
diff --git a/.github/workflows/smoke.yml b/.github/workflows/smoke.yml
index aa91f91c3d..bf76d29064 100644
--- a/.github/workflows/smoke.yml
+++ b/.github/workflows/smoke.yml
@@ -39,9 +39,6 @@ jobs:
           - os: ubuntu-24.04-arm
             cc: gcc
             cxx: g++
-          - os: macos-14            # arm64
-            cc: cc
-            cxx: c++
           - os: macos-15            # arm64
             cc: cc
             cxx: c++