diff --git a/.github/workflows/release.yml b/.github/workflows/release.yml
index 0bd7f96..a3c559e 100644
--- a/.github/workflows/release.yml
+++ b/.github/workflows/release.yml
@@ -4,14 +4,19 @@ on:
   push:
     tags:
       - 'v*.*.*'
+  # A change to this file runs the build and SBOM jobs on its PR, so a broken
+  # release path shows up at review rather than at the next tag. The release
+  # job is skipped on PRs.
+  pull_request:
+    paths:
+      - '.github/workflows/release.yml'
   workflow_dispatch:
     inputs:
       version:
-        description: 'Version to release (e.g., v0.1.0)'
+        description: 'Existing tag to release (e.g., v0.1.0). The build checks out this tag.'
         required: true
 permissions:
-  contents: write
-  id-token: write
+  contents: read
 jobs:
   build:
     name: Build Package
@@ -21,15 +26,32 @@ jobs:
       matrix:
         os: [ubuntu-latest, macos-latest, windows-latest]
         julia-version: ['1.10']
+    defaults:
+      run:
+        shell: bash
     steps:
+      # On a manual run, build the tag being released, not the default branch,
+      # so the artefacts match the tagged and registered tree. The ref is
+      # qualified as refs/tags/: checkout resolves a bare name to a branch of
+      # that name before a tag (src/ref-helper.ts). On other events
+      # inputs.version is empty, ref is empty, and checkout uses the triggering ref.
       - uses: actions/checkout@3d3c42e5aac5ba805825da76410c181273ba90b1 # v4
+        with:
+          ref: ${{ inputs.version && format('refs/tags/{0}', inputs.version) || '' }}
       - uses: julia-actions/setup-julia@fa02766e078afaaf09b14210362cee14137e6a32 # v3.0.2
         with:
           version: ${{ matrix.julia-version }}
       - uses: julia-actions/cache@e32267b41e0fa7df82a3d53e8c7273620d52c586 # v3.4.0
+      # A library release is tested the way users install it: resolved fresh
+      # from Project.toml [compat].
+      - name: Ignore any committed manifest
+        run: rm -f Manifest.toml
+      # AcceleratorGate is registered in the hyperpolymath registry, not in
+      # General.
+      - name: Add registries
+        run: julia -e 'using Pkg; Pkg.Registry.add("General"); Pkg.Registry.add(Pkg.RegistrySpec(url="https://github.com/hyperpolymath/julia-professional-registry"))'
       - name: Build and test
-        run: |
-          julia --project -e 'using Pkg; Pkg.build(); Pkg.test()'
+        run: julia --project -e 'using Pkg; Pkg.build(); Pkg.test()'
       - name: Package artifacts
         run: |
           mkdir -p dist
@@ -46,15 +68,32 @@ jobs:
     needs: build
     steps:
       - uses: actions/checkout@3d3c42e5aac5ba805825da76410c181273ba90b1 # v4
+        with:
+          ref: ${{ inputs.version && format('refs/tags/{0}', inputs.version) || '' }}
       - uses: julia-actions/setup-julia@fa02766e078afaaf09b14210362cee14137e6a32 # v3.0.2
         with:
           version: '1.10'
+      # Pkg.dependencies() needs a resolved environment. JSON is not a
+      # dependency of this package, so it is loaded from a throwaway
+      # environment after the component list has been read.
       - name: Generate SBOM
         run: |
+          rm -f Manifest.toml
+          julia -e 'using Pkg; Pkg.Registry.add("General"); Pkg.Registry.add(Pkg.RegistrySpec(url="https://github.com/hyperpolymath/julia-professional-registry"))'
           julia --project -e '
-            using Pkg, JSON
+            using Pkg
+            Pkg.instantiate()
             pkg_info = Pkg.project()
-            deps = Pkg.dependencies()
+            components = [
+              Dict(
+                "type" => "library",
+                "name" => info.name,
+                "version" => info.version === nothing ? "stdlib" : string(info.version)
+              ) for (uuid, info) in Pkg.dependencies() if info.is_direct_dep
+            ]
+            Pkg.activate(temp=true)
+            Pkg.add("JSON")
+            using JSON
             sbom = Dict(
               "bomFormat" => "CycloneDX",
               "specVersion" => "1.4",
@@ -66,13 +105,7 @@ jobs:
                   "version" => string(pkg_info.version)
                 )
               ),
-              "components" => [
-                Dict(
-                  "type" => "library",
-                  "name" => string(uuid),
-                  "version" => string(info.version)
-                ) for (uuid, info) in deps if info.is_direct_dep
-              ]
+              "components" => components
             )
             open("sbom.json", "w") do f
               JSON.print(f, sbom, 2)
@@ -85,6 +118,7 @@ jobs:
           path: sbom.json
   release:
     name: Create Release
+    if: github.event_name != 'pull_request'
     runs-on: ubuntu-latest
     timeout-minutes: 15
     needs: [build, sbom]
@@ -93,7 +127,28 @@ jobs:
       id-token: write
       attestations: write
     steps:
-      - uses: actions/checkout@3d3c42e5aac5ba805825da76410c181273ba90b1 # v4
+      # Refuse anything but an existing vX.Y.Z tag, so a mistyped manual run
+      # cannot make action-gh-release create a new tag on the default branch.
+      - name: Extract version
+        id: version
+        env:
+          EVENT_NAME: ${{ github.event_name }}
+          INPUT_VERSION: ${{ inputs.version }}
+        run: |
+          if [ "$EVENT_NAME" = "workflow_dispatch" ]; then
+            version="$INPUT_VERSION"
+          else
+            version="${GITHUB_REF#refs/tags/}"
+          fi
+          if ! printf '%s\n' "$version" | grep -Eq '^v[0-9]+\.[0-9]+\.[0-9]+$'; then
+            echo "::error::the version to release is not of the form vX.Y.Z"
+            exit 1
+          fi
+          if ! git ls-remote --exit-code --tags "$GITHUB_SERVER_URL/$GITHUB_REPOSITORY" "refs/tags/$version" > /dev/null; then
+            echo "::error::tag $version does not exist; push the tag first"
+            exit 1
+          fi
+          echo "version=$version" >> "$GITHUB_OUTPUT"
       - name: Download artifacts
         uses: actions/download-artifact@3e5f45b2cfb9172054b4087a40e8e0b5a5461e7c # v8.0.1
         with:
@@ -103,19 +158,11 @@ jobs:
           mkdir -p release
           find release-artifacts -type f -exec cp {} release/ \;
           cd release
-          sha256sum * > checksums.txt
+          sha256sum -- * > checksums.txt
       - name: Attest build provenance
         uses: actions/attest-build-provenance@4d101475d8b20a2381f78447822ac1eab6504dd8 # v4.2.2
         with:
           subject-path: 'release/*'
-      - name: Extract version
-        id: version
-        run: |
-          if [ "${{ github.event_name }}" = "workflow_dispatch" ]; then
-            echo "version=${{ github.event.inputs.version }}" >> $GITHUB_OUTPUT
-          else
-            echo "version=${GITHUB_REF#refs/tags/}" >> $GITHUB_OUTPUT
-          fi
       - name: Create GitHub Release
         uses: softprops/action-gh-release@efb35369e0ad2afab669f228072c1b0d510eae64 # v2
         with:
@@ -133,6 +180,7 @@ jobs:
 
             ```bash
             sha256sum -c checksums.txt
+            gh attestation verify <file> -R hyperpolymath/SMTLib.jl
             ```
           files: release/*
           draft: false