diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index a18e6b5..d9192db 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@4cda84d5c5c54efe2404f9d843567869ab1699d4 # stable
         with:
           components: rustfmt, clippy
-      - uses: taiki-e/install-action@just
+      - uses: taiki-e/install-action@1e7bd61f4b270e749b15995a9e7aa0fe7449dc13 # 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@2c7215f132e9ebf062739d9130488b56d53c060c # 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@5eef0a1a229795b1ebd3e9f72dd41d63a959d20f # nextest
+      - uses: taiki-e/install-action@c44f6b046f1c29ae5918b1e0bfdbb2f1813836fd # v2
         with:
           tool: jj-cli
       - name: Build
diff --git a/.github/workflows/release.yml b/.github/workflows/release.yml
index 174cf91..952daef 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@4cda84d5c5c54efe2404f9d843567869ab1699d4 # stable
       - name: Install cargo release
         uses: taiki-e/install-action@3235f8901fd37ffed0052b276cec25a362fb82e9 # v2
         with: