diff --git a/.github/actions/ref_from_sha/branch_from_sha.js b/.github/actions/ref_from_sha/branch_from_sha.cjs
similarity index 100%
rename from .github/actions/ref_from_sha/branch_from_sha.js
rename to .github/actions/ref_from_sha/branch_from_sha.cjs
diff --git a/.github/actions/ref_from_sha/index.cjs b/.github/actions/ref_from_sha/index.cjs
new file mode 100644
index 000000000..9356f47e3
--- /dev/null
+++ b/.github/actions/ref_from_sha/index.cjs
@@ -0,0 +1,70 @@
+/**
+ * Given the GITHUB_SHA, find the pr and ref it is the head of.
+ *
+ * Intended for use with Vercel `deployment_status` events which incorrectly
+ * set the GITHUB_REF to the commit SHA value.
+ */
+
+const core = require("@actions/core");
+const github = require("@actions/github");
+
+const prFromSha = require("./pr_from_sha");
+const branchFromSha = require("./branch_from_sha");
+
+async function run() {
+  try {
+    const githubToken = core.getInput("github_token");
+
+    const octokit = github.getOctokit(githubToken);
+
+    const owner = github.context.payload.repository.owner.login;
+    const repo = github.context.payload.repository.name;
+    if (!owner || !repo) {
+      throw new Error(
+        `Could not determine repo details, got: owner "${owner} and repo "${repo}".`,
+      );
+    }
+
+    let sha = github.context.sha;
+    if (!sha) {
+      throw new Error(`SHA not supplied.`);
+    }
+
+    // Get the *first* PR that has the given SHA as the head of the feature branch.
+    const pullRequest = await prFromSha(octokit, { owner, repo }, sha);
+    let headRef;
+    let prNumber = undefined;
+    if (pullRequest !== null) {
+      // There is a PR with this SHA as the head of the feature branch
+      headRef = pullRequest.head.ref;
+      // DEBUG
+      core.debug(`Pull Request:\n${JSON.stringify(pullRequest, null, 2)}`);
+      prNumber = pullRequest.number;
+    } else {
+      // The SHA is not on a PR feature branch, get from first matching general branch, prefer `main`.
+      const branch = await branchFromSha(octokit, { owner, repo }, sha);
+      if (branch !== null) {
+        headRef = branch.name;
+      } else {
+        // No refs to be had.
+        core.error(`Could not find pull request or branch for SHA: ${sha}`);
+      }
+    }
+
+    /** @todo handle release tags? v1.2.3 */
+    const fullHeadRef = `refs/heads/${headRef}`;
+    core.setOutput("branch_name", headRef);
+    core.setOutput("head_ref", fullHeadRef);
+    core.setOutput("pr_number", prNumber);
+    core.info(
+      `Found pull request or branch for for SHA: ${sha} with ref: ${fullHeadRef}.${
+        prNumber ? `Found PR number: ${prNumber}` : ""
+      }`,
+    );
+  } catch (error) {
+    core.error(error);
+    core.setFailed(error.message);
+  }
+}
+
+run();
diff --git a/.github/actions/ref_from_sha/index.js b/.github/actions/ref_from_sha/index.js
index 9356f47e3..9d7c8f7c4 100644
--- a/.github/actions/ref_from_sha/index.js
+++ b/.github/actions/ref_from_sha/index.js
@@ -33,7 +33,7 @@ async function run() {
     // Get the *first* PR that has the given SHA as the head of the feature branch.
     const pullRequest = await prFromSha(octokit, { owner, repo }, sha);
     let headRef;
-    let prNumber = undefined;
+    let prNumber;
     if (pullRequest !== null) {
       // There is a PR with this SHA as the head of the feature branch
       headRef = pullRequest.head.ref;
diff --git a/.github/actions/ref_from_sha/pr_from_sha.js b/.github/actions/ref_from_sha/pr_from_sha.cjs
similarity index 100%
rename from .github/actions/ref_from_sha/pr_from_sha.js
rename to .github/actions/ref_from_sha/pr_from_sha.cjs
diff --git a/.github/actions/ref_from_sha/test/e2e.js b/.github/actions/ref_from_sha/test/e2e.cjs
similarity index 100%
rename from .github/actions/ref_from_sha/test/e2e.js
rename to .github/actions/ref_from_sha/test/e2e.cjs
diff --git a/.github/workflows/playwright.yml b/.github/workflows/playwright.yml
index 415a33f65..ffe5958cd 100644
--- a/.github/workflows/playwright.yml
+++ b/.github/workflows/playwright.yml
@@ -28,6 +28,7 @@ jobs:
         id: ref_from_sha
         with:
           github_token: ${{ secrets.GITHUB_TOKEN }}
+          entrypoint: ./index.cjs
       - name: Install Playwright
         run: npx playwright install --with-deps chromium webkit
       - name: Inject Doppler env vars
diff --git a/.github/workflows/post_deployment.yml b/.github/workflows/post_deployment.yml
index 6b1d6c6ba..e20f76463 100644
--- a/.github/workflows/post_deployment.yml
+++ b/.github/workflows/post_deployment.yml
@@ -35,6 +35,7 @@ jobs:
         id: ref_from_sha
         with:
           github_token: ${{ secrets.GITHUB_TOKEN }}
+          entrypoint: ./index.cjs
 
       - uses: mcky/find-and-replace-pull-request-body@v1.1.6-mcky
         if: ${{ steps.ref_from_sha.outputs.pr_number }}