diff --git a/.github/workflows/reusable-tag-on-release-merge.yml b/.github/workflows/reusable-tag-on-release-merge.yml
index 09f4975..21ecf8b 100644
--- a/.github/workflows/reusable-tag-on-release-merge.yml
+++ b/.github/workflows/reusable-tag-on-release-merge.yml
@@ -2,10 +2,43 @@
 # changed), create the vX.Y.Z tag and GitHub Release with the App token --
 # required so the created release triggers the publish workflow (a plain
 # GITHUB_TOKEN release does not trigger downstream workflows).
+#
+# The manual path is the recovery for a push event GitHub never delivered (a
+# merge that ran no workflow at all). A caller that also triggers on
+# `workflow_dispatch` gets it by passing its dispatch input through:
+#
+#   on:
+#     push: { branches: [main], paths: [VERSION] }
+#     workflow_dispatch:
+#       inputs:
+#         release: { description: "Version or merge SHA; blank = VERSION as it stands", required: false, default: "" }
+#         dry-run: { type: boolean, default: false }
+#   jobs:
+#     tag:
+#       uses: PyDevices/.github/.github/workflows/reusable-tag-on-release-merge.yml@<tag>
+#       with: { release: "${{ inputs.release }}", dry-run: "${{ inputs.dry-run == true }}" }
+#       secrets: inherit
+#
+# A manual run tags the commit that brought VERSION to the version being
+# tagged, never an arbitrary one, and applies the same version grammar as the
+# push path. Callers that don't dispatch are unchanged.
 name: Reusable tag on release merge
 
 on:
-  workflow_call: {}
+  workflow_call:
+    inputs:
+      release:
+        description: >-
+          Manual runs only. The version (X.Y.Z[{a|b|rc}N|.devN]) or the merge
+          SHA to tag. Blank tags VERSION as it stands on the default branch.
+        type: string
+        required: false
+        default: ""
+      dry-run:
+        description: Manual runs only. Say what would be tagged, tag nothing.
+        type: boolean
+        required: false
+        default: false
 
 permissions:
   contents: read
@@ -16,10 +49,12 @@ jobs:
     steps:
       - uses: actions/checkout@v7
         with:
-          fetch-depth: 2
+          # A manual run walks VERSION's history and needs the tags.
+          fetch-depth: ${{ github.event_name == 'workflow_dispatch' && '0' || '2' }}
 
       - name: Detect a VERSION change
         id: detect
+        if: github.event_name != 'workflow_dispatch'
         run: |
           if git diff --quiet HEAD^ HEAD -- VERSION 2>/dev/null; then
             echo "changed=false" >> "$GITHUB_OUTPUT"; exit 0
@@ -43,8 +78,79 @@ jobs:
           echo "changed=true" >> "$GITHUB_OUTPUT"
           echo "version=$V" >> "$GITHUB_OUTPUT"
 
+      - name: Resolve a manual release
+        id: manual
+        if: github.event_name == 'workflow_dispatch'
+        env:
+          RELEASE: ${{ inputs.release }}
+          DRY_RUN: ${{ inputs.dry-run }}
+          DEFAULT_BRANCH: ${{ github.event.repository.default_branch }}
+        run: |
+          set -eu
+          GRAMMAR='^[0-9]+\.[0-9]+\.[0-9]+((a|b|rc)[0-9]+|\.dev[0-9]+)?$'
+          if [ "$GITHUB_REF" != "refs/heads/$DEFAULT_BRANCH" ]; then
+            echo "::error::Run this on $DEFAULT_BRANCH, not $GITHUB_REF; refusing to tag."
+            exit 1
+          fi
+          R=$(printf %s "$RELEASE" | tr -d '[:space:]')
+          WANT_SHA=""
+          if [ -z "$R" ]; then
+            V=$(tr -d '[:space:]' < VERSION)
+          elif [[ "$R" =~ $GRAMMAR ]]; then
+            V=$R
+          elif [[ "$R" =~ ^[0-9a-fA-F]{7,40}$ ]]; then
+            WANT_SHA=$(git rev-parse -q --verify "$R^{commit}") || {
+              echo "::error::No commit '$R' in this repository; refusing to tag."; exit 1; }
+            if ! git merge-base --is-ancestor "$WANT_SHA" HEAD; then
+              echo "::error::$WANT_SHA is not on $DEFAULT_BRANCH; refusing to tag."
+              exit 1
+            fi
+            V=$(git show "$WANT_SHA:VERSION" | tr -d '[:space:]')
+          else
+            echo "::error::'$R' is neither a release version nor a commit SHA; refusing to tag."
+            exit 1
+          fi
+          # Same grammar as the push path: a placeholder is not a release.
+          if [[ ! "$V" =~ $GRAMMAR ]]; then
+            echo "::error::VERSION is '$V', not a release version X.Y.Z[{a|b|rc}N|.devN]; refusing to tag."
+            exit 1
+          fi
+          if git rev-parse -q --verify "refs/tags/v$V" >/dev/null; then
+            echo "Tag v$V already exists; nothing to do."
+            echo "changed=false" >> "$GITHUB_OUTPUT"; exit 0
+          fi
+          # The commit on the default branch that brought VERSION to $V (the
+          # oldest of a run of commits that leave it there): what the push
+          # run would have tagged.
+          SHA=""
+          for C in $(git log --first-parent --format=%H -- VERSION); do
+            if [ "$(git show "$C:VERSION" | tr -d '[:space:]')" = "$V" ]; then
+              SHA=$C
+            elif [ -n "$SHA" ]; then
+              break
+            fi
+          done
+          if [ -z "$SHA" ]; then
+            echo "::error::No commit on $DEFAULT_BRANCH sets VERSION to $V; refusing to tag."
+            exit 1
+          fi
+          if [ -n "$WANT_SHA" ] && [ "$WANT_SHA" != "$SHA" ]; then
+            echo "::error::$WANT_SHA is not the commit that set VERSION to $V; that is $SHA; refusing to tag."
+            exit 1
+          fi
+          if [ "$DRY_RUN" = "true" ]; then
+            echo "Dry run: would tag v$V at $SHA. Nothing was tagged."
+            echo "changed=false" >> "$GITHUB_OUTPUT"; exit 0
+          fi
+          echo "Tagging v$V at $SHA"
+          {
+            echo "changed=true"
+            echo "version=$V"
+            echo "sha=$SHA"
+          } >> "$GITHUB_OUTPUT"
+
       - name: Mint App token
-        if: steps.detect.outputs.changed == 'true'
+        if: steps.detect.outputs.changed == 'true' || steps.manual.outputs.changed == 'true'
         id: app-token
         uses: actions/create-github-app-token@v3
         with:
@@ -52,12 +158,13 @@ jobs:
           private-key: ${{ secrets.PYDEVICES_APP_PRIVATE_KEY }}
 
       - name: Create tag and Release
-        if: steps.detect.outputs.changed == 'true'
+        if: steps.detect.outputs.changed == 'true' || steps.manual.outputs.changed == 'true'
         env:
           GH_TOKEN: ${{ steps.app-token.outputs.token }}
-          V: ${{ steps.detect.outputs.version }}
+          V: ${{ steps.detect.outputs.version || steps.manual.outputs.version }}
+          TARGET: ${{ steps.manual.outputs.sha || github.sha }}
         run: |
           PRERELEASE=""
           [[ "$V" =~ (a|b|rc)[0-9]+$|\.dev[0-9]+$ ]] && PRERELEASE="--prerelease"
-          gh release create "v$V" --target "$GITHUB_SHA" \
+          gh release create "v$V" --target "$TARGET" \
             --title "v$V" --generate-notes $PRERELEASE
diff --git a/docs/publishing-automation.md b/docs/publishing-automation.md
index 09424bd..51dd5f9 100644
--- a/docs/publishing-automation.md
+++ b/docs/publishing-automation.md
@@ -240,6 +240,16 @@ The App token is required here, not incidental: **a Release created with the
 default `GITHUB_TOKEN` does not trigger `on: release` workflows**, so the
 publish chain below would silently never fire.
 
+If GitHub never delivers the push event for a merge (it has happened: a merge
+that ran no workflow at all), run the repository's tag workflow by hand from
+`main`. A caller that also triggers on `workflow_dispatch` and passes its
+`release` and `dry-run` inputs through (the shape is in the header comment of
+`reusable-tag-on-release-merge.yml`) gets a manual path that tags the commit
+that brought `VERSION` to the version, checks the same version grammar as the
+push path, and does nothing if the tag exists. Leave `release` blank to tag
+`VERSION` as it stands, or give a version or that merge's SHA. Set `dry-run` to
+see what it would tag without tagging anything.
+
 ### 4. Publish release packages runs from the Release event
 
 `reusable-publish-release-packages.yml` resolves and validates the `vX.Y.Z`
diff --git a/tests/test_tag_on_release_merge.py b/tests/test_tag_on_release_merge.py
index cfb3321..746949b 100644
--- a/tests/test_tag_on_release_merge.py
+++ b/tests/test_tag_on_release_merge.py
@@ -28,6 +28,16 @@ def detect_step_shell() -> str:
     return textwrap.dedent(block[begin:end])
 
 
+def manual_step_shell() -> str:
+    """The `run:` body of the Resolve a manual release step."""
+    text = TAG_WORKFLOW.read_text(encoding="utf-8")
+    start = text.index("- name: Resolve a manual release")
+    block = text[start:]
+    begin = block.index("run: |\n") + len("run: |\n")
+    end = block.index("\n\n      - name:", begin)
+    return textwrap.dedent(block[begin:end])
+
+
 def git(cwd: Path, *args: str) -> None:
     subprocess.run(["git", "-C", str(cwd), *args], check=True, capture_output=True)
 
@@ -174,5 +184,145 @@ def test_an_already_tagged_version_is_a_no_op(self):
             self.assertIn("changed=false", output.read_text(encoding="utf-8"))
 
 
+class ManualReleaseTests(unittest.TestCase):
+    """The workflow_dispatch path: recovery for a merge event GitHub lost."""
+
+    def run_manual(self, history, release="", *, dry_run="false",
+                   ref="refs/heads/main", tags=(), setup=None):
+        """`history` is a list of VERSION contents, one commit each (None means
+        a commit that leaves VERSION alone). Returns (result, shas)."""
+        with tempfile.TemporaryDirectory() as tmp:
+            root = Path(tmp)
+            git(root, "init", "-q", "-b", "main")
+            git(root, "config", "user.email", "test@example.invalid")
+            git(root, "config", "user.name", "Test")
+            shas = []
+            for number, version in enumerate(history):
+                if version is None:
+                    (root / "other.txt").write_text(f"{number}\n", encoding="utf-8")
+                    git(root, "add", "other.txt")
+                else:
+                    (root / "VERSION").write_text(version + "\n", encoding="utf-8")
+                    git(root, "add", "VERSION")
+                git(root, "commit", "-q", "-m", f"commit {number}")
+                shas.append(subprocess.run(
+                    ["git", "-C", str(root), "rev-parse", "HEAD"],
+                    check=True, capture_output=True, text=True).stdout.strip())
+            for tag in tags:
+                git(root, "tag", tag)
+            if setup:
+                setup(root, shas)
+            script = root / "manual.sh"
+            script.write_text(manual_step_shell(), encoding="utf-8")
+            output = root / "github_output"
+            output.touch()
+            release = release(shas) if callable(release) else release
+            result = subprocess.run(
+                ["bash", "-e", str(script)],
+                cwd=root,
+                env={"PATH": "/usr/bin:/bin", "GITHUB_OUTPUT": str(output),
+                     "GITHUB_REF": ref, "DEFAULT_BRANCH": "main",
+                     "RELEASE": release, "DRY_RUN": dry_run},
+                capture_output=True, text=True, check=False)
+            result.github_output = output.read_text(encoding="utf-8")  # type: ignore[attr-defined]
+            return result, shas
+
+    def assert_tags(self, result, version, sha):
+        self.assertEqual(result.returncode, 0, result.stdout + result.stderr)
+        self.assertIn("changed=true", result.github_output)
+        self.assertIn(f"version={version}", result.github_output)
+        self.assertIn(f"sha={sha}", result.github_output)
+
+    def assert_refused(self, result):
+        self.assertEqual(result.returncode, 1, result.stdout + result.stderr)
+        self.assertIn("refusing to tag", result.stdout + result.stderr)
+        self.assertNotIn("changed=true", result.github_output)
+
+    def test_blank_tags_the_commit_that_set_the_current_version(self):
+        result, shas = self.run_manual(["0.1.0", None, "0.2.0", None, None])
+        self.assert_tags(result, "0.2.0", shas[2])
+
+    def test_a_named_version_finds_its_own_commit(self):
+        result, shas = self.run_manual(
+            ["0.1.0", "0.2.0", None, "0.3.0"], release="0.2.0")
+        self.assert_tags(result, "0.2.0", shas[1])
+
+    def test_a_run_of_commits_at_one_version_tags_the_first(self):
+        result, shas = self.run_manual(["0.1.0", "0.2.0", "0.2.0\n", None])
+        self.assert_tags(result, "0.2.0", shas[1])
+
+    def test_a_merge_sha_works(self):
+        result, shas = self.run_manual(
+            ["0.1.0", "0.2.0", "0.3.0"], release=lambda s: s[1][:10])
+        self.assert_tags(result, "0.2.0", shas[1])
+
+    def test_a_sha_that_did_not_set_the_version_is_refused(self):
+        result, shas = self.run_manual(
+            ["0.1.0", "0.2.0", None, None], release=lambda s: s[3])
+        self.assert_refused(result)
+        self.assertIn(f"that is {shas[1]}", result.stdout + result.stderr)
+
+    def test_a_placeholder_version_is_refused(self):
+        self.assert_refused(self.run_manual(["0.1.0", "0.0.0-PLACEHOLDER"])[0])
+
+    def test_a_named_version_that_was_never_set_is_refused(self):
+        self.assert_refused(self.run_manual(["0.1.0", "0.2.0"], release="0.9.0")[0])
+
+    def test_a_version_not_matching_the_grammar_is_refused(self):
+        self.assert_refused(self.run_manual(["0.1.0", "0.2.0"], release="v0.2.0")[0])
+
+    def test_a_sha_whose_version_is_a_placeholder_is_refused(self):
+        result, _ = self.run_manual(
+            ["0.1.0", "junk", "0.2.0"], release=lambda s: s[1])
+        self.assert_refused(result)
+
+    def test_an_unknown_sha_is_refused(self):
+        self.assert_refused(
+            self.run_manual(["0.1.0", "0.2.0"], release="deadbeef")[0])
+
+    def test_a_sha_off_the_default_branch_is_refused(self):
+        def branch(root, shas):
+            git(root, "checkout", "-q", "-b", "side", shas[0])
+            (root / "VERSION").write_text("0.9.0\n", encoding="utf-8")
+            git(root, "commit", "-q", "-am", "side")
+            side = subprocess.run(["git", "-C", str(root), "rev-parse", "HEAD"],
+                                  check=True, capture_output=True, text=True).stdout.strip()
+            git(root, "checkout", "-q", "main")
+            shas.append(side)
+        result, _ = self.run_manual(
+            ["0.1.0", "0.2.0"], release=lambda s: s[2], setup=branch)
+        self.assert_refused(result)
+
+    def test_a_branch_other_than_the_default_is_refused(self):
+        result, _ = self.run_manual(["0.1.0", "0.2.0"], ref="refs/heads/feature")
+        self.assert_refused(result)
+
+    def test_an_existing_tag_is_a_no_op(self):
+        result, _ = self.run_manual(["0.1.0", "0.2.0"], tags=["v0.2.0"])
+        self.assertEqual(result.returncode, 0, result.stdout + result.stderr)
+        self.assertIn("changed=false", result.github_output)
+        self.assertNotIn("changed=true", result.github_output)
+
+    def test_a_dry_run_says_what_it_would_tag_and_tags_nothing(self):
+        result, shas = self.run_manual(["0.1.0", "0.2.0"], dry_run="true")
+        self.assertEqual(result.returncode, 0, result.stdout + result.stderr)
+        self.assertIn(f"would tag v0.2.0 at {shas[1]}", result.stdout)
+        self.assertNotIn("changed=true", result.github_output)
+
+
+class WorkflowShapeTests(unittest.TestCase):
+    def test_the_push_path_is_not_taken_on_a_manual_run(self):
+        text = TAG_WORKFLOW.read_text(encoding="utf-8")
+        detect = text[text.index("- name: Detect a VERSION change"):]
+        self.assertIn("if: github.event_name != 'workflow_dispatch'",
+                      detect[:detect.index("run:")])
+
+    def test_inputs_are_optional_so_existing_callers_keep_working(self):
+        text = TAG_WORKFLOW.read_text(encoding="utf-8")
+        inputs = text[text.index("workflow_call:"):text.index("permissions:")]
+        self.assertEqual(inputs.count("required: false"), 2)
+        self.assertNotIn("required: true", inputs)
+
+
 if __name__ == "__main__":
     unittest.main()