diff --git a/dist/index.js b/dist/index.js
index 8b4a6ea..de11e31 100644
--- a/dist/index.js
+++ b/dist/index.js
@@ -52,7 +52,7 @@ function attest(options) {
         // Store the attestation
         let attestationID;
         if (options.skipWrite !== true) {
-            attestationID = yield (0, store_1.writeAttestation)((0, bundle_1.bundleToJSON)(bundle), options.token);
+            attestationID = yield (0, store_1.writeAttestation)((0, bundle_1.bundleToJSON)(bundle), options.token, { headers: options.headers });
         }
         return toAttestation(bundle, attestationID);
     });
@@ -249,6 +249,10 @@ const core_1 = __nccwpck_require__(42186);
 const http_client_1 = __nccwpck_require__(96255);
 const jose = __importStar(__nccwpck_require__(34061));
 const OIDC_AUDIENCE = 'nobody';
+const VALID_SERVER_URLS = [
+    'https://github.com',
+    new RegExp('^https://[a-z0-9-]+\\.ghe\\.com$')
+];
 const REQUIRED_CLAIMS = [
     'iss',
     'ref',
@@ -264,6 +268,7 @@ const REQUIRED_CLAIMS = [
     'run_attempt'
 ];
 const getIDTokenClaims = (issuer) => __awaiter(void 0, void 0, void 0, function* () {
+    issuer = issuer || getIssuer();
     try {
         const token = yield (0, core_1.getIDToken)(OIDC_AUDIENCE);
         const claims = yield decodeOIDCToken(token, issuer);
@@ -307,6 +312,19 @@ function assertClaimSet(claims) {
         throw new Error(`Missing claims: ${missingClaims.join(', ')}`);
     }
 }
+// Derive the current OIDC issuer based on the server URL
+function getIssuer() {
+    const serverURL = process.env.GITHUB_SERVER_URL || 'https://github.com';
+    // Ensure the server URL is a valid GitHub server URL
+    if (!VALID_SERVER_URLS.some(valid_url => serverURL.match(valid_url))) {
+        throw new Error(`Invalid server URL: ${serverURL}`);
+    }
+    let host = new URL(serverURL).hostname;
+    if (host === 'github.com') {
+        host = 'githubusercontent.com';
+    }
+    return `https://token.actions.${host}`;
+}
 //# sourceMappingURL=oidc.js.map
 
 /***/ }),
@@ -331,7 +349,6 @@ const attest_1 = __nccwpck_require__(46373);
 const oidc_1 = __nccwpck_require__(95847);
 const SLSA_PREDICATE_V1_TYPE = 'https://slsa.dev/provenance/v1';
 const GITHUB_BUILD_TYPE = 'https://actions.github.io/buildtypes/workflow/v1';
-const DEFAULT_ISSUER = 'https://token.actions.githubusercontent.com';
 /**
  * Builds an SLSA (Supply Chain Levels for Software Artifacts) provenance
  * predicate using the GitHub Actions Workflow build type.
@@ -341,7 +358,7 @@ const DEFAULT_ISSUER = 'https://token.actions.githubusercontent.com';
  * issuer.
  * @returns The SLSA provenance predicate.
  */
-const buildSLSAProvenancePredicate = (issuer = DEFAULT_ISSUER) => __awaiter(void 0, void 0, void 0, function* () {
+const buildSLSAProvenancePredicate = (issuer) => __awaiter(void 0, void 0, void 0, function* () {
     const serverURL = process.env.GITHUB_SERVER_URL;
     const claims = yield (0, oidc_1.getIDTokenClaims)(issuer);
     // Split just the path and ref from the workflow string.
@@ -540,6 +557,7 @@ const writeAttestation = (attestation, token, options = {}) => __awaiter(void 0,
         const response = yield octokit.request(CREATE_ATTESTATION_REQUEST, {
             owner: github.context.repo.owner,
             repo: github.context.repo.repo,
+            headers: options.headers,
             data: { bundle: attestation }
         });
         const data = typeof response.data == 'string'
@@ -106928,7 +106946,9 @@ async function generateAttestation(manifestDigest, semverTag, options) {
         token: options.token,
         sigstore: 'github',
         // Always store the attestation using the GitHub Attestations API
-        skipWrite: false
+        skipWrite: false,
+        // Identify the attestation to our API as an Immutable Action
+        headers: { 'X-GitHub-Publish-Action': subjectName }
     });
 }
 function removePrefix(str, prefix) {
diff --git a/package-lock.json b/package-lock.json
index 803f02f..12663b9 100644
--- a/package-lock.json
+++ b/package-lock.json
@@ -9,7 +9,7 @@
       "version": "0.0.0",
       "license": "MIT",
       "dependencies": {
-        "@actions/attest": "^1.3.1",
+        "@actions/attest": "^1.4.0",
         "@actions/core": "^1.10.1",
         "@actions/exec": "^1.1.1",
         "@actions/github": "^6.0.0",
@@ -56,9 +56,9 @@
       }
     },
     "node_modules/@actions/attest": {
-      "version": "1.3.1",
-      "resolved": "https://registry.npmjs.org/@actions/attest/-/attest-1.3.1.tgz",
-      "integrity": "sha512-4q09+4QvNROKHsjpusyRhtmUz8kHpFg45n5LqJAYrMQh8mU5O5t9shpGU3Z44rtUebgBTH8Ge0lTzLxfUOVvHw==",
+      "version": "1.4.0",
+      "resolved": "https://registry.npmjs.org/@actions/attest/-/attest-1.4.0.tgz",
+      "integrity": "sha512-vyiv8VuONuIqktf4DdLqYL5sKEPPNTBlmjik+DP+7HqTiOgmrBa4Nn1eKh50aHjxa6tz+VSIYPaw0XG3Zc7zJw==",
       "dependencies": {
         "@actions/core": "^1.10.1",
         "@actions/github": "^6.0.0",
diff --git a/package.json b/package.json
index 76f707a..31af38a 100644
--- a/package.json
+++ b/package.json
@@ -67,7 +67,7 @@
     ]
   },
   "dependencies": {
-    "@actions/attest": "^1.3.1",
+    "@actions/attest": "^1.4.0",
     "@actions/core": "^1.10.1",
     "@actions/exec": "^1.1.1",
     "@actions/github": "^6.0.0",
diff --git a/src/main.ts b/src/main.ts
index e930a4b..a9fe215 100644
--- a/src/main.ts
+++ b/src/main.ts
@@ -128,7 +128,9 @@ async function generateAttestation(
     token: options.token,
     sigstore: 'github',
     // Always store the attestation using the GitHub Attestations API
-    skipWrite: false
+    skipWrite: false,
+    // Identify the attestation to our API as an Immutable Action
+    headers: { 'X-GitHub-Publish-Action': subjectName }
   })
 }