diff --git a/.github/workflows/conformance.yml b/.github/workflows/conformance.yml
index 95159e7..8f35f66 100644
--- a/.github/workflows/conformance.yml
+++ b/.github/workflows/conformance.yml
@@ -25,7 +25,7 @@ jobs:
     name: Rust (drs-core) — full test suite
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v4
+      - uses: actions/checkout@v6
 
       - name: Install Rust toolchain
         uses: dtolnay/rust-toolchain@stable
@@ -47,7 +47,7 @@ jobs:
     name: Go (drs-verify) — full test suite
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v4
+      - uses: actions/checkout@v6
 
       - name: Set up Go
         uses: actions/setup-go@v6
@@ -63,7 +63,7 @@ jobs:
     name: TypeScript (drs-sdk) — full test suite
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v4
+      - uses: actions/checkout@v6
 
       - name: Set up Node.js
         uses: actions/setup-node@v6
@@ -87,7 +87,7 @@ jobs:
     name: TypeScript (drs-mcp-client)
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v4
+      - uses: actions/checkout@v6
 
       - name: Set up Node.js
         uses: actions/setup-node@v6
@@ -111,7 +111,7 @@ jobs:
     name: TypeScript (drs-mcp-server)
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v4
+      - uses: actions/checkout@v6
 
       - name: Set up Node.js
         uses: actions/setup-node@v6
@@ -135,7 +135,7 @@ jobs:
     name: Fixture integrity check
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v4
+      - uses: actions/checkout@v6
 
       - name: Compute fixture checksum
         run: |
diff --git a/.github/workflows/docs-deploy.yml b/.github/workflows/docs-deploy.yml
index 8635bb0..fc59cff 100644
--- a/.github/workflows/docs-deploy.yml
+++ b/.github/workflows/docs-deploy.yml
@@ -12,7 +12,7 @@ jobs:
   deploy:
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v4
+      - uses: actions/checkout@v6
 
       - name: Install mdBook
         uses: peaceiris/actions-mdbook@v2
diff --git a/.github/workflows/e2e.yml b/.github/workflows/e2e.yml
index 0572b3b..0c2d625 100644
--- a/.github/workflows/e2e.yml
+++ b/.github/workflows/e2e.yml
@@ -26,7 +26,7 @@ jobs:
     runs-on: ubuntu-latest
     if: github.event_name == 'pull_request' || github.event_name == 'push'
     steps:
-      - uses: actions/checkout@v4
+      - uses: actions/checkout@v6
 
       - name: Set up Docker Buildx
         uses: docker/setup-buildx-action@v4
@@ -65,7 +65,7 @@ jobs:
     runs-on: ubuntu-latest
     if: startsWith(github.ref, 'refs/tags/v')
     steps:
-      - uses: actions/checkout@v4
+      - uses: actions/checkout@v6
 
       - name: Setup Node
         uses: actions/setup-node@v6
diff --git a/.github/workflows/publish.yml b/.github/workflows/publish.yml
index 933a551..039f291 100644
--- a/.github/workflows/publish.yml
+++ b/.github/workflows/publish.yml
@@ -25,7 +25,7 @@ jobs:
     name: Run tests before publishing
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v4
+      - uses: actions/checkout@v6
 
       - name: Install Rust
         uses: dtolnay/rust-toolchain@stable
@@ -70,7 +70,7 @@ jobs:
     needs: test
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v4
+      - uses: actions/checkout@v6
 
       - name: Install pnpm
         uses: pnpm/action-setup@v6
@@ -110,7 +110,7 @@ jobs:
     needs: test
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v4
+      - uses: actions/checkout@v6
 
       - name: Install Rust
         uses: dtolnay/rust-toolchain@stable
@@ -139,7 +139,7 @@ jobs:
     needs: test
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v4
+      - uses: actions/checkout@v6
 
       - name: Set up Docker Buildx
         uses: docker/setup-buildx-action@v4
diff --git a/.github/workflows/security.yml b/.github/workflows/security.yml
index e95992d..9cb7493 100644
--- a/.github/workflows/security.yml
+++ b/.github/workflows/security.yml
@@ -27,7 +27,7 @@ jobs:
     name: Trivy filesystem scan (code + dependencies)
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v4
+      - uses: actions/checkout@v6
 
       # First pass: table format, non-fatal — so findings are visible in the
       # workflow log. The second pass below is the gate that fails the build.
@@ -66,7 +66,7 @@ jobs:
     name: govulncheck (Go-specific CVEs)
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v4
+      - uses: actions/checkout@v6
 
       - name: Setup Go
         uses: actions/setup-go@v6
@@ -85,7 +85,7 @@ jobs:
     name: cargo audit (Rust advisories)
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v4
+      - uses: actions/checkout@v6
 
       - name: Install Rust
         uses: dtolnay/rust-toolchain@stable
@@ -101,7 +101,7 @@ jobs:
     name: pnpm audit (npm advisories)
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v4
+      - uses: actions/checkout@v6
 
       - name: Install pnpm
         uses: pnpm/action-setup@v6