diff --git a/.github/workflows/proto-version-check.yml b/.github/workflows/proto-version-check.yml
index ea300419d..b888f98c1 100644
--- a/.github/workflows/proto-version-check.yml
+++ b/.github/workflows/proto-version-check.yml
@@ -3,60 +3,73 @@ name: Proto Version Check
 on:
   pull_request:
     paths:
+      - "**/*.proto"
       - "**/*.pb.go"
+      - "**/generate.sh"
+      - "proto-tools.env"
+      - ".github/workflows/proto-version-check.yml"
 
 jobs:
-  check-proto-versions:
+  regenerate-and-diff:
+    name: Regenerate proto and verify no drift
     runs-on: ubuntu-latest
     steps:
-      - name: Check for proto tool version changes
-        uses: actions/github-script@v7
+      - name: Checkout
+        uses: actions/checkout@v4
+
+      - name: Load pinned proto toolchain versions
+        run: |
+          # shellcheck source=/dev/null
+          . ./proto-tools.env
+          {
+            echo "PROTOC_VERSION=${PROTOC_VERSION}"
+            echo "PROTOC_GEN_GO_VERSION=${PROTOC_GEN_GO_VERSION}"
+            echo "PROTOC_GEN_GO_GRPC_VERSION=${PROTOC_GEN_GO_GRPC_VERSION}"
+          } >> "$GITHUB_ENV"
+
+      - name: Setup Go
+        uses: actions/setup-go@v5
         with:
-          script: |
-            const files = await github.paginate(github.rest.pulls.listFiles, {
-              owner: context.repo.owner,
-              repo: context.repo.repo,
-              pull_number: context.issue.number,
-              per_page: 100,
-            });
+          go-version-file: go.mod
 
-            const pbFiles = files.filter(f => f.filename.endsWith('.pb.go'));
-            const missingPatch = pbFiles.filter(f => !f.patch).map(f => f.filename);
-            if (missingPatch.length > 0) {
-              core.setFailed(
-                `Cannot inspect patch data for:\n` +
-                missingPatch.map(f => `- ${f}`).join('\n') +
-                `\nThis can happen with very large PRs. Verify proto versions manually.`
-              );
-              return;
-            }
-            const versionPattern = /^[+-]\s*\/\/\s+protoc(?:-gen-go)?\s+v[\d.]+/;
-            const violations = [];
+      - name: Setup protoc
+        uses: arduino/setup-protoc@v3
+        with:
+          version: ${{ env.PROTOC_VERSION }}
+          repo-token: ${{ secrets.GITHUB_TOKEN }}
 
-            for (const file of pbFiles) {
-              const changed = file.patch
-                .split('\n')
-                .filter(line => versionPattern.test(line));
-              if (changed.length > 0) {
-                violations.push({
-                  file: file.filename,
-                  lines: changed,
-                });
-              }
-            }
+      - name: Install protoc plugins
+        run: |
+          go install "google.golang.org/protobuf/cmd/protoc-gen-go@${PROTOC_GEN_GO_VERSION}"
+          go install "google.golang.org/grpc/cmd/protoc-gen-go-grpc@${PROTOC_GEN_GO_GRPC_VERSION}"
+          echo "$(go env GOPATH)/bin" >> "$GITHUB_PATH"
 
-            if (violations.length > 0) {
-              const details = violations.map(v =>
-                `${v.file}:\n${v.lines.map(l => '  ' + l).join('\n')}`
-              ).join('\n\n');
+      - name: Verify protoc version matches pin
+        run: |
+          actual=$(protoc --version | awk '{print $2}')
+          if [ "$actual" != "$PROTOC_VERSION" ]; then
+            echo "::error::protoc $actual does not match pinned $PROTOC_VERSION"
+            exit 1
+          fi
 
-              core.setFailed(
-                `Proto version strings changed in generated files.\n` +
-                `This usually means the wrong protoc or protoc-gen-go version was used.\n` +
-                `Regenerate with the matching tool versions.\n\n` +
-                details
-              );
-              return;
-            }
+      - name: Regenerate all proto bindings
+        run: |
+          set -euo pipefail
+          for script in \
+            client/proto/generate.sh \
+            shared/signal/proto/generate.sh \
+            shared/management/proto/generate.sh \
+            flow/proto/generate.sh \
+            encryption/testprotos/generate.sh; do
+            echo "::group::$script"
+            bash "$script"
+            echo "::endgroup::"
+          done
 
-            console.log('No proto version string changes detected');
+      - name: Fail if regeneration changed any tracked file
+        run: |
+          if ! git diff --exit-code; then
+            echo "::error::Generated proto files drift from .proto sources or pinned tool versions."
+            echo "Run the generate.sh scripts locally with the toolchain in proto-tools.env and commit the result."
+            exit 1
+          fi