diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index a18e6b5..5123aec 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -21,10 +21,10 @@ jobs:
           # We need to fetch the entire history so clippy can run the
           # e2e-example/client build script.
           fetch-depth: 0
-      - uses: dtolnay/rust-toolchain@stable
+      - uses: dtolnay/rust-toolchain@6bed0761d98439e5a578e2877258200ad565ba87 # stable
         with:
           components: rustfmt, clippy
-      - uses: taiki-e/install-action@just
+      - uses: taiki-e/install-action@0fcb49d29f9345a853257a633d34efac54f50c7a # just
       - uses: Swatinem/rust-cache@98c8021b550208e191a6a3145459bfc9fb29c4c0 # v2.8.0
         with:
           key: partition-${{ matrix.partition }}
@@ -54,14 +54,14 @@ jobs:
           # We need to fetch the entire history so the tests can run merge-base
           # operations.
           fetch-depth: 0
-      - uses: dtolnay/rust-toolchain@master
+      - uses: dtolnay/rust-toolchain@d1031067263f94b142dd6c0ce24c5eb9d02d52a0 # master
         with:
           toolchain: ${{ matrix.rust-version }}
       - uses: Swatinem/rust-cache@98c8021b550208e191a6a3145459bfc9fb29c4c0 # v2.8.0
         with:
           key: partition-${{ matrix.partition }}
-      - uses: taiki-e/install-action@nextest
-      - uses: taiki-e/install-action@v2
+      - uses: taiki-e/install-action@ef6302df50adb496d123b03ae2b53322d688ffa1 # nextest
+      - uses: taiki-e/install-action@7b8d4719ee4aaa279bdf55df38dacb9ebfe12a6c # v2
         with:
           tool: jj-cli
       - name: Build
diff --git a/.github/workflows/release.yml b/.github/workflows/release.yml
index 213975b..8c7357a 100644
--- a/.github/workflows/release.yml
+++ b/.github/workflows/release.yml
@@ -21,7 +21,7 @@ jobs:
       - uses: rust-lang/crates-io-auth-action@v1
         id: auth
       - name: Install Rust
-        uses: dtolnay/rust-toolchain@stable
+        uses: dtolnay/rust-toolchain@6bed0761d98439e5a578e2877258200ad565ba87 # stable
       - name: Install cargo release
         uses: taiki-e/install-action@b6ff580856c41316412a0b9b60540fbc6f8c82cc # v2
         with: