diff --git a/.github/workflows/build.yml b/.github/workflows/build.yml
index 0501a07..43b902d 100644
--- a/.github/workflows/build.yml
+++ b/.github/workflows/build.yml
@@ -3,22 +3,62 @@ name: Build
 on:
   pull_request:
 
+permissions:
+  contents: read
+  actions: write  # required for actions/upload-artifact
+
+concurrency:
+  group: build-${{ github.event.pull_request.number || github.ref }}
+  cancel-in-progress: true
+
 jobs:
-  build:
-    name: Build
+
+  # ── 1. Format check (fast, ~30s, no Docker needed) ──────────────────────────
+  style:
+    name: Code Style
     runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@34e114876b0b11c390a56381ad16ebd13914f8d5  # v4
+
+      - name: Set up Java
+        uses: actions/setup-java@c1e323688fd81a25caa38c78aa6df2d33d3e20d9  # v4
+        with:
+          java-version: 21
+          distribution: 'zulu'
+
+      - name: Cache Gradle
+        uses: actions/cache@0057852bfaa89a56745cba8c7296529d2fc39830  # v4
+        with:
+          path: ~/.gradle/caches
+          key: ${{ runner.os }}-gradle-${{ hashFiles('**/*.gradle') }}-${{ hashFiles('**/gradle.properties') }}
+          restore-keys: |
+            ${{ runner.os }}-gradle-
+
+      - name: Cache Gradle wrapper
+        uses: actions/cache@0057852bfaa89a56745cba8c7296529d2fc39830  # v4
+        with:
+          path: ~/.gradle/wrapper
+          key: ${{ runner.os }}-gradlew-${{ hashFiles('**/gradlew') }}
+          restore-keys: ${{ runner.os }}-gradlew-
 
+      - name: Spotless check
+        run: ./gradlew spotlessCheck -S
+
+  # ── 2. Compile (fast, ~1–2 min, no tests, no Docker) ────────────────────────
+  compile:
+    name: Compile
+    runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v4
+      - uses: actions/checkout@34e114876b0b11c390a56381ad16ebd13914f8d5  # v4
 
       - name: Set up Java
-        uses: actions/setup-java@v4
+        uses: actions/setup-java@c1e323688fd81a25caa38c78aa6df2d33d3e20d9  # v4
         with:
           java-version: 21
           distribution: 'zulu'
 
       - name: Cache Gradle
-        uses: actions/cache@v4
+        uses: actions/cache@0057852bfaa89a56745cba8c7296529d2fc39830  # v4
         with:
           path: ~/.gradle/caches
           key: ${{ runner.os }}-gradle-${{ hashFiles('**/*.gradle') }}-${{ hashFiles('**/gradle.properties') }}
@@ -26,24 +66,85 @@ jobs:
             ${{ runner.os }}-gradle-
 
       - name: Cache Gradle wrapper
-        uses: actions/cache@v4
+        uses: actions/cache@0057852bfaa89a56745cba8c7296529d2fc39830  # v4
         with:
           path: ~/.gradle/wrapper
           key: ${{ runner.os }}-gradlew-${{ hashFiles('**/gradlew') }}
           restore-keys: ${{ runner.os }}-gradlew-
 
-      - name: Code Style Check
-        run: |
-          ./gradlew spotlessCheck -S
+      - name: Compile (no tests)
+        run: ./gradlew assemble -S
 
-      - name: Build
-        run: |
-          ./gradlew build -S
+  # ── 3. Unit tests (requires Docker for testcontainers/Redis) ────────────────
+  test:
+    name: Test
+    runs-on: ubuntu-latest
+    needs: compile
+    steps:
+      - uses: actions/checkout@34e114876b0b11c390a56381ad16ebd13914f8d5  # v4
+
+      - name: Set up Java
+        uses: actions/setup-java@c1e323688fd81a25caa38c78aa6df2d33d3e20d9  # v4
+        with:
+          java-version: 21
+          distribution: 'zulu'
+
+      - name: Cache Gradle
+        uses: actions/cache@0057852bfaa89a56745cba8c7296529d2fc39830  # v4
+        with:
+          path: ~/.gradle/caches
+          key: ${{ runner.os }}-gradle-${{ hashFiles('**/*.gradle') }}-${{ hashFiles('**/gradle.properties') }}
+          restore-keys: |
+            ${{ runner.os }}-gradle-
+
+      - name: Cache Gradle wrapper
+        uses: actions/cache@0057852bfaa89a56745cba8c7296529d2fc39830  # v4
+        with:
+          path: ~/.gradle/wrapper
+          key: ${{ runner.os }}-gradlew-${{ hashFiles('**/gradlew') }}
+          restore-keys: ${{ runner.os }}-gradlew-
+
+      - name: Run tests
+        run: ./gradlew :core:test :demos:langchain4j-vcr:test :demos:spring-ai-vcr:test -S
 
       - name: Upload test reports
         if: failure()
-        uses: actions/upload-artifact@v4
+        uses: actions/upload-artifact@ea165f8d65b6e75b540449e92b4886f43607fa02  # v4
         with:
           name: test-reports
           path: |
-            build/reports/tests/aggregate/
+            core/build/reports/tests/test/
+            demos/langchain4j-vcr/build/reports/tests/test/
+            demos/spring-ai-vcr/build/reports/tests/test/
+
+  # ── 4. Static analysis (runs in parallel with tests after compile) ───────────
+  spotbugs:
+    name: SpotBugs
+    runs-on: ubuntu-latest
+    needs: compile
+    steps:
+      - uses: actions/checkout@34e114876b0b11c390a56381ad16ebd13914f8d5  # v4
+
+      - name: Set up Java
+        uses: actions/setup-java@c1e323688fd81a25caa38c78aa6df2d33d3e20d9  # v4
+        with:
+          java-version: 21
+          distribution: 'zulu'
+
+      - name: Cache Gradle
+        uses: actions/cache@0057852bfaa89a56745cba8c7296529d2fc39830  # v4
+        with:
+          path: ~/.gradle/caches
+          key: ${{ runner.os }}-gradle-${{ hashFiles('**/*.gradle') }}-${{ hashFiles('**/gradle.properties') }}
+          restore-keys: |
+            ${{ runner.os }}-gradle-
+
+      - name: Cache Gradle wrapper
+        uses: actions/cache@0057852bfaa89a56745cba8c7296529d2fc39830  # v4
+        with:
+          path: ~/.gradle/wrapper
+          key: ${{ runner.os }}-gradlew-${{ hashFiles('**/gradlew') }}
+          restore-keys: ${{ runner.os }}-gradlew-
+
+      - name: SpotBugs
+        run: ./gradlew :core:spotbugsMain -S
diff --git a/.github/workflows/docs.yml b/.github/workflows/docs.yml
index cbb7f69..c2e3ea8 100644
--- a/.github/workflows/docs.yml
+++ b/.github/workflows/docs.yml
@@ -23,23 +23,23 @@ jobs:
       url: ${{ steps.deployment.outputs.page_url }}
     steps:
       - name: Checkout
-        uses: actions/checkout@v4
+        uses: actions/checkout@34e114876b0b11c390a56381ad16ebd13914f8d5 # v4
         with:
           fetch-depth: 0
 
       - name: Set up Java
-        uses: actions/setup-java@v4
+        uses: actions/setup-java@c1e323688fd81a25caa38c78aa6df2d33d3e20d9 # v4
         with:
           java-version: 21
           distribution: 'zulu'
 
       - name: Set up Node.js
-        uses: actions/setup-node@v4
+        uses: actions/setup-node@49933ea5288caeca8642d1e84afbd3f7d6820020 # v4
         with:
           node-version: 20
 
       - name: Cache Gradle dependencies
-        uses: actions/cache@v4
+        uses: actions/cache@0057852bfaa89a56745cba8c7296529d2fc39830 # v4
         with:
           path: ~/.gradle/caches
           key: ${{ runner.os }}-gradle-${{ hashFiles('**/*.gradle*', '**/gradle-wrapper.properties') }}
@@ -47,7 +47,7 @@ jobs:
             ${{ runner.os }}-gradle-
 
       - name: Cache Gradle wrapper
-        uses: actions/cache@v4
+        uses: actions/cache@0057852bfaa89a56745cba8c7296529d2fc39830 # v4
         with:
           path: ~/.gradle/wrapper
           key: ${{ runner.os }}-gradle-wrapper-${{ hashFiles('**/gradle-wrapper.properties') }}
@@ -72,13 +72,13 @@ jobs:
         run: touch docs/build/site/.nojekyll
 
       - name: Setup Pages
-        uses: actions/configure-pages@v4
+        uses: actions/configure-pages@1f0c5cde4bc74cd7e1254d0cb4de8d49e9068c7d # v4
 
       - name: Upload artifact
-        uses: actions/upload-pages-artifact@v3
+        uses: actions/upload-pages-artifact@56afc609e74202658d3ffba0e8f6dda462b719fa # v3
         with:
           path: 'docs/build/site'
 
       - name: Deploy to GitHub Pages
         id: deployment
-        uses: actions/deploy-pages@v4
+        uses: actions/deploy-pages@d6db90164ac5ed86f2b6aed7e0febac5b3c0c03e # v4
diff --git a/.github/workflows/early-access.yml b/.github/workflows/early-access.yml
index 1aa191b..7ace733 100644
--- a/.github/workflows/early-access.yml
+++ b/.github/workflows/early-access.yml
@@ -4,29 +4,32 @@ on:
   push:
     branches: [ main ]
 
+permissions:
+  contents: write
+  actions: write  # required for actions/upload-artifact
+
+concurrency:
+  group: early-access-${{ github.ref }}
+  cancel-in-progress: true
+
 jobs:
   earlyaccess:
     name: 'Early Access'
     runs-on: ubuntu-latest
     steps:
-      - name: Cancel previous run
-        uses: styfle/cancel-workflow-action@0.12.1
-        with:
-          access_token: ${{ secrets.GIT_ACCESS_TOKEN }}
-
       - name: Checkout
-        uses: actions/checkout@v4
+        uses: actions/checkout@34e114876b0b11c390a56381ad16ebd13914f8d5 # v4
         with:
           fetch-depth: 0
 
       - name: Set up Java
-        uses: actions/setup-java@v4
+        uses: actions/setup-java@c1e323688fd81a25caa38c78aa6df2d33d3e20d9 # v4
         with:
           java-version: 21
           distribution: 'zulu'
 
       - name: Cache Gradle
-        uses: actions/cache@v4
+        uses: actions/cache@0057852bfaa89a56745cba8c7296529d2fc39830 # v4
         with:
           path: ~/.gradle/caches
           key: ${{ runner.os }}-gradle-${{ hashFiles('**/*.gradle') }}-${{ hashFiles('**/gradle.properties') }}
@@ -34,7 +37,7 @@ jobs:
             ${{ runner.os }}-gradle-
 
       - name: Cache Gradle wrapper
-        uses: actions/cache@v4
+        uses: actions/cache@0057852bfaa89a56745cba8c7296529d2fc39830 # v4
         with:
           path: ~/.gradle/wrapper
           key: ${{ runner.os }}-gradlew-${{ hashFiles('**/gradlew') }}
@@ -46,7 +49,7 @@ jobs:
 
       - name: Upload test reports
         if: failure()
-        uses: actions/upload-artifact@v4
+        uses: actions/upload-artifact@ea165f8d65b6e75b540449e92b4886f43607fa02 # v4
         with:
           name: test-report
           path: |
@@ -79,7 +82,7 @@ jobs:
 
       - name: Release Snapshot
         if: ${{ steps.vars.outputs.SHOULD_RELEASE_SNAPSHOT == 'true' }}
-        uses: jreleaser/release-action@v2
+        uses: jreleaser/release-action@90ac653bb9c79d11179e65d81499f3f34527dcd5 # 2.5.0
         with:
           arguments: release
           version: 'latest'
@@ -97,7 +100,7 @@ jobs:
 
       - name: JReleaser output
         if: always()
-        uses: actions/upload-artifact@v4
+        uses: actions/upload-artifact@ea165f8d65b6e75b540449e92b4886f43607fa02 # v4
         with:
           name: artifact
           path: |
diff --git a/.github/workflows/release.yml b/.github/workflows/release.yml
index a953b47..ee6c1a3 100644
--- a/.github/workflows/release.yml
+++ b/.github/workflows/release.yml
@@ -8,29 +8,32 @@ on:
         required: true
         type: string
 
+permissions:
+  contents: write
+  actions: write  # required for actions/upload-artifact
+
+concurrency:
+  group: release-${{ github.ref }}
+  cancel-in-progress: false
+
 jobs:
   release:
     name: Release
     runs-on: ubuntu-latest
     steps:
-      - name: Cancel previous run
-        uses: styfle/cancel-workflow-action@0.12.1
-        with:
-          access_token: ${{ secrets.GIT_ACCESS_TOKEN }}
-
       - name: Checkout
-        uses: actions/checkout@v4
+        uses: actions/checkout@34e114876b0b11c390a56381ad16ebd13914f8d5 # v4
         with:
           fetch-depth: 0
 
       - name: Set up Java
-        uses: actions/setup-java@v4
+        uses: actions/setup-java@c1e323688fd81a25caa38c78aa6df2d33d3e20d9 # v4
         with:
           java-version: 21
           distribution: 'zulu'
 
       - name: Cache Gradle
-        uses: actions/cache@v4
+        uses: actions/cache@0057852bfaa89a56745cba8c7296529d2fc39830 # v4
         with:
           path: ~/.gradle/caches
           key: ${{ runner.os }}-gradle-${{ hashFiles('**/*.gradle') }}-${{ hashFiles('**/gradle.properties') }}
@@ -38,7 +41,7 @@ jobs:
             ${{ runner.os }}-gradle-
 
       - name: Cache Gradle wrapper
-        uses: actions/cache@v4
+        uses: actions/cache@0057852bfaa89a56745cba8c7296529d2fc39830 # v4
         with:
           path: ~/.gradle/wrapper
           key: ${{ runner.os }}-gradlew-${{ hashFiles('**/gradlew') }}
@@ -66,21 +69,21 @@ jobs:
 
       - name: Upload test reports
         if: failure()
-        uses: actions/upload-artifact@v4
+        uses: actions/upload-artifact@ea165f8d65b6e75b540449e92b4886f43607fa02 # v4
         with:
           name: test-reports
           path: |
             build/reports/tests/aggregate/
 
       - name: Assemble
-        uses: jreleaser/release-action@v2
+        uses: jreleaser/release-action@90ac653bb9c79d11179e65d81499f3f34527dcd5 # 2.5.0
         with:
           arguments: assemble
         env:
           JRELEASER_PROJECT_VERSION: ${{ inputs.version }}
 
       - name: Release
-        uses: jreleaser/release-action@v2
+        uses: jreleaser/release-action@90ac653bb9c79d11179e65d81499f3f34527dcd5 # 2.5.0
         with:
           arguments: full-release
         env:
@@ -97,7 +100,7 @@ jobs:
 
       - name: JReleaser output
         if: always()
-        uses: actions/upload-artifact@v4
+        uses: actions/upload-artifact@ea165f8d65b6e75b540449e92b4886f43607fa02 # v4
         with:
           name: artifact
           path: |
@@ -105,7 +108,7 @@ jobs:
             out/jreleaser/output.properties
 
       - name: Trigger documentation build
-        uses: peter-evans/repository-dispatch@v2
+        uses: peter-evans/repository-dispatch@bf47d102fdb849e755b0b0023ea3e81a44b6f570 # v2
         with:
           token: ${{ secrets.GIT_ACCESS_TOKEN }}
           event-type: docs-build