diff --git a/.github/workflows/build_kernel.yaml b/.github/workflows/build_kernel.yaml
index 9a17e059..a90b729d 100644
--- a/.github/workflows/build_kernel.yaml
+++ b/.github/workflows/build_kernel.yaml
@@ -10,6 +10,10 @@ on:
       - "*.md"
   workflow_dispatch:
 
+concurrency:
+  group: ${{ github.workflow }}-${{ github.event.pull_request.number || github.ref }}
+  cancel-in-progress: true
+
 jobs:
   build:
     name: Build kernels (${{ matrix.arch }})
diff --git a/.github/workflows/build_kernel_macos.yaml b/.github/workflows/build_kernel_macos.yaml
index 03fd552a..2bc9a38f 100644
--- a/.github/workflows/build_kernel_macos.yaml
+++ b/.github/workflows/build_kernel_macos.yaml
@@ -10,6 +10,10 @@ on:
       - "*.md"
   workflow_dispatch:
 
+concurrency:
+  group: ${{ github.workflow }}-${{ github.event.pull_request.number || github.ref }}
+  cancel-in-progress: true
+
 jobs:
   build:
     name: Build kernel
diff --git a/.github/workflows/build_kernel_rocm.yaml b/.github/workflows/build_kernel_rocm.yaml
index 4b6205b1..9f33d85f 100644
--- a/.github/workflows/build_kernel_rocm.yaml
+++ b/.github/workflows/build_kernel_rocm.yaml
@@ -10,6 +10,10 @@ on:
       - "*.md"
   workflow_dispatch:
 
+concurrency:
+  group: ${{ github.workflow }}-${{ github.event.pull_request.number || github.ref }}
+  cancel-in-progress: true
+
 jobs:
   build:
     name: Build kernels (ROCm)
diff --git a/.github/workflows/build_kernel_windows.yaml b/.github/workflows/build_kernel_windows.yaml
index 6082f7ad..7d94d362 100644
--- a/.github/workflows/build_kernel_windows.yaml
+++ b/.github/workflows/build_kernel_windows.yaml
@@ -10,6 +10,10 @@ on:
       - "*.md"
   workflow_dispatch:
 
+concurrency:
+  group: ${{ github.workflow }}-${{ github.event.pull_request.number || github.ref }}
+  cancel-in-progress: true
+
 jobs:
   build:
     strategy:
diff --git a/.github/workflows/build_kernel_xpu.yaml b/.github/workflows/build_kernel_xpu.yaml
index 7a284846..148f1e53 100644
--- a/.github/workflows/build_kernel_xpu.yaml
+++ b/.github/workflows/build_kernel_xpu.yaml
@@ -10,6 +10,10 @@ on:
       - "*.md"
   workflow_dispatch:
 
+concurrency:
+  group: ${{ github.workflow }}-${{ github.event.pull_request.number || github.ref }}
+  cancel-in-progress: true
+
 jobs:
   build:
     name: Build kernel
diff --git a/.github/workflows/check_variants.yaml b/.github/workflows/check_variants.yaml
index 45ce5d6b..96d5f4f5 100644
--- a/.github/workflows/check_variants.yaml
+++ b/.github/workflows/check_variants.yaml
@@ -10,6 +10,10 @@ on:
       - "*.md"
   workflow_dispatch:
 
+concurrency:
+  group: ${{ github.workflow }}-${{ github.event.pull_request.number || github.ref }}
+  cancel-in-progress: true
+
 jobs:
   build:
     name: Check build variants
diff --git a/.github/workflows/kernel-builder-cli-docs.yaml b/.github/workflows/kernel-builder-cli-docs.yaml
index 606da7e6..d707fdf1 100644
--- a/.github/workflows/kernel-builder-cli-docs.yaml
+++ b/.github/workflows/kernel-builder-cli-docs.yaml
@@ -12,6 +12,10 @@ on:
     branches:
       - main
 
+concurrency:
+  group: ${{ github.workflow }}-${{ github.event.pull_request.number || github.ref }}
+  cancel-in-progress: true
+
 jobs:
   check-cli-docs:
     runs-on: ubuntu-latest
diff --git a/.github/workflows/kernels_data_python_release.yaml b/.github/workflows/kernels_data_python_release.yaml
index 491efb25..266ba006 100644
--- a/.github/workflows/kernels_data_python_release.yaml
+++ b/.github/workflows/kernels_data_python_release.yaml
@@ -8,6 +8,7 @@
 #  - publish step switched from `uv publish` + API token to
 #    `PyO3/maturin-action` + PyPI trusted publishing (see plan.md §3a, §3b)
 #  - pull_request trigger gained `paths-ignore` for docs-only PRs
+#  - concurrency block added (cancel-in-progress only for PRs, never on tag/main)
 name: CI
 
 on:
@@ -23,6 +24,10 @@ on:
       - "*.md"
   workflow_dispatch:
 
+concurrency:
+  group: ${{ github.workflow }}-${{ github.ref }}
+  cancel-in-progress: ${{ github.event_name == 'pull_request' }}
+
 permissions:
   contents: read
 
diff --git a/.github/workflows/lint.yml b/.github/workflows/lint.yml
index 2b351d8b..e2cdb854 100644
--- a/.github/workflows/lint.yml
+++ b/.github/workflows/lint.yml
@@ -6,6 +6,10 @@ on:
       - "docs/**"
       - "*.md"
 
+concurrency:
+  group: ${{ github.workflow }}-${{ github.event.pull_request.number || github.ref }}
+  cancel-in-progress: true
+
 env:
   RUFF_VERSION: "0.15.10"
   GRIFFE_VERSION: "1.15.0"
diff --git a/.github/workflows/nix_checks.yml b/.github/workflows/nix_checks.yml
index 22e31ee0..28444d59 100644
--- a/.github/workflows/nix_checks.yml
+++ b/.github/workflows/nix_checks.yml
@@ -10,6 +10,10 @@ on:
       - "*.md"
   workflow_dispatch:
 
+concurrency:
+  group: ${{ github.workflow }}-${{ github.event.pull_request.number || github.ref }}
+  cancel-in-progress: true
+
 jobs:
   build:
     name: Nix checks
diff --git a/.github/workflows/rust.yaml b/.github/workflows/rust.yaml
index f737c078..d8b82e8f 100644
--- a/.github/workflows/rust.yaml
+++ b/.github/workflows/rust.yaml
@@ -7,6 +7,10 @@ on:
       - "docs/**"
       - "*.md"
 
+concurrency:
+  group: ${{ github.workflow }}-${{ github.event.pull_request.number || github.ref }}
+  cancel-in-progress: true
+
 jobs:
   fmt:
     name: Rustfmt
diff --git a/.github/workflows/test_e2e.yaml b/.github/workflows/test_e2e.yaml
index 8f3eca53..5627f55a 100644
--- a/.github/workflows/test_e2e.yaml
+++ b/.github/workflows/test_e2e.yaml
@@ -13,6 +13,10 @@ on:
       - ".github/workflows/test_e2e.yaml"
   workflow_dispatch:
 
+concurrency:
+  group: ${{ github.workflow }}-${{ github.event.pull_request.number || github.ref }}
+  cancel-in-progress: true
+
 env:
   HF_ENDPOINT: https://hub-ci.huggingface.co
   HF_TOKEN: ${{ secrets.HF_HUB_CI_TOKEN }}
diff --git a/.github/workflows/test_extra_commands.yaml b/.github/workflows/test_extra_commands.yaml
index 84b54af4..af86e68a 100644
--- a/.github/workflows/test_extra_commands.yaml
+++ b/.github/workflows/test_extra_commands.yaml
@@ -10,6 +10,10 @@ on:
       - "*.md"
   workflow_dispatch:
 
+concurrency:
+  group: ${{ github.workflow }}-${{ github.event.pull_request.number || github.ref }}
+  cancel-in-progress: true
+
 jobs:
   build:
     name: Build kernel