diff --git a/dist/restore-only/index.js b/dist/restore-only/index.js
index 37c95cb..c2e6021 100644
--- a/dist/restore-only/index.js
+++ b/dist/restore-only/index.js
@@ -92559,15 +92559,21 @@ function restoreFromGCS(_paths_1, primaryKey_1) {
         const archiveFolder = yield utils.createTempDirectory();
         const archivePath = path.join(archiveFolder, utils.getCacheFileName(compressionMethod));
         const keys = [primaryKey, ...restoreKeys];
-        const gcsPath = yield findFileOnGCS(storage, bucket, pathPrefix, keys, compressionMethod);
-        if (!gcsPath) {
+        const match = yield findFileOnGCS(storage, bucket, pathPrefix, keys, compressionMethod);
+        if (!match) {
             core.info(`No matching cache found`);
             return undefined;
         }
+        // Preserve the @actions/cache contract: return the matched cache KEY
+        // (primaryKey or a restoreKey), not the GCS object path. The caller
+        // (restoreImpl) compares the return value against primaryKey to set the
+        // `cache-hit` output — returning the gcs path makes `cache-hit` always
+        // false, re-triggering downstream install/build steps that gate on it.
+        const { key: matchedKey, path: gcsPath } = match;
         // If lookup only, just return the key
         if (options === null || options === void 0 ? void 0 : options.lookupOnly) {
-            core.info(`Cache found in GCS with key: ${gcsPath}`);
-            return gcsPath;
+            core.info(`Cache found in GCS with key: ${matchedKey}`);
+            return matchedKey;
         }
         try {
             core.info(`Downloading from GCS: ${bucket}/${gcsPath}`);
@@ -92580,7 +92586,7 @@ function restoreFromGCS(_paths_1, primaryKey_1) {
             core.info(`Cache Size: ~${Math.round(archiveFileSize / (1024 * 1024))} MB (${archiveFileSize} B)`);
             yield (0, tar_1.extractTar)(archivePath, compressionMethod);
             core.info("Cache restored successfully");
-            return gcsPath;
+            return matchedKey;
         }
         catch (error) {
             core.warning(`Failed to restore: ${error.message}`);
@@ -92649,7 +92655,7 @@ function findFileOnGCS(storage, bucket, pathPrefix, keys, compressionMethod) {
             const gcsPath = getGCSPath(pathPrefix, key, compressionMethod);
             if (yield checkFileExists(storage, bucket, gcsPath)) {
                 core.info(`Found file on bucket: ${bucket} with key: ${gcsPath}`);
-                return gcsPath;
+                return { key, path: gcsPath };
             }
         }
         return undefined;
diff --git a/dist/restore/index.js b/dist/restore/index.js
index ed3cf87..0d6b9f5 100644
--- a/dist/restore/index.js
+++ b/dist/restore/index.js
@@ -92559,15 +92559,21 @@ function restoreFromGCS(_paths_1, primaryKey_1) {
         const archiveFolder = yield utils.createTempDirectory();
         const archivePath = path.join(archiveFolder, utils.getCacheFileName(compressionMethod));
         const keys = [primaryKey, ...restoreKeys];
-        const gcsPath = yield findFileOnGCS(storage, bucket, pathPrefix, keys, compressionMethod);
-        if (!gcsPath) {
+        const match = yield findFileOnGCS(storage, bucket, pathPrefix, keys, compressionMethod);
+        if (!match) {
             core.info(`No matching cache found`);
             return undefined;
         }
+        // Preserve the @actions/cache contract: return the matched cache KEY
+        // (primaryKey or a restoreKey), not the GCS object path. The caller
+        // (restoreImpl) compares the return value against primaryKey to set the
+        // `cache-hit` output — returning the gcs path makes `cache-hit` always
+        // false, re-triggering downstream install/build steps that gate on it.
+        const { key: matchedKey, path: gcsPath } = match;
         // If lookup only, just return the key
         if (options === null || options === void 0 ? void 0 : options.lookupOnly) {
-            core.info(`Cache found in GCS with key: ${gcsPath}`);
-            return gcsPath;
+            core.info(`Cache found in GCS with key: ${matchedKey}`);
+            return matchedKey;
         }
         try {
             core.info(`Downloading from GCS: ${bucket}/${gcsPath}`);
@@ -92580,7 +92586,7 @@ function restoreFromGCS(_paths_1, primaryKey_1) {
             core.info(`Cache Size: ~${Math.round(archiveFileSize / (1024 * 1024))} MB (${archiveFileSize} B)`);
             yield (0, tar_1.extractTar)(archivePath, compressionMethod);
             core.info("Cache restored successfully");
-            return gcsPath;
+            return matchedKey;
         }
         catch (error) {
             core.warning(`Failed to restore: ${error.message}`);
@@ -92649,7 +92655,7 @@ function findFileOnGCS(storage, bucket, pathPrefix, keys, compressionMethod) {
             const gcsPath = getGCSPath(pathPrefix, key, compressionMethod);
             if (yield checkFileExists(storage, bucket, gcsPath)) {
                 core.info(`Found file on bucket: ${bucket} with key: ${gcsPath}`);
-                return gcsPath;
+                return { key, path: gcsPath };
             }
         }
         return undefined;
diff --git a/dist/save-only/index.js b/dist/save-only/index.js
index 4af28e4..df35931 100644
--- a/dist/save-only/index.js
+++ b/dist/save-only/index.js
@@ -92572,15 +92572,21 @@ function restoreFromGCS(_paths_1, primaryKey_1) {
         const archiveFolder = yield utils.createTempDirectory();
         const archivePath = path.join(archiveFolder, utils.getCacheFileName(compressionMethod));
         const keys = [primaryKey, ...restoreKeys];
-        const gcsPath = yield findFileOnGCS(storage, bucket, pathPrefix, keys, compressionMethod);
-        if (!gcsPath) {
+        const match = yield findFileOnGCS(storage, bucket, pathPrefix, keys, compressionMethod);
+        if (!match) {
             core.info(`No matching cache found`);
             return undefined;
         }
+        // Preserve the @actions/cache contract: return the matched cache KEY
+        // (primaryKey or a restoreKey), not the GCS object path. The caller
+        // (restoreImpl) compares the return value against primaryKey to set the
+        // `cache-hit` output — returning the gcs path makes `cache-hit` always
+        // false, re-triggering downstream install/build steps that gate on it.
+        const { key: matchedKey, path: gcsPath } = match;
         // If lookup only, just return the key
         if (options === null || options === void 0 ? void 0 : options.lookupOnly) {
-            core.info(`Cache found in GCS with key: ${gcsPath}`);
-            return gcsPath;
+            core.info(`Cache found in GCS with key: ${matchedKey}`);
+            return matchedKey;
         }
         try {
             core.info(`Downloading from GCS: ${bucket}/${gcsPath}`);
@@ -92593,7 +92599,7 @@ function restoreFromGCS(_paths_1, primaryKey_1) {
             core.info(`Cache Size: ~${Math.round(archiveFileSize / (1024 * 1024))} MB (${archiveFileSize} B)`);
             yield (0, tar_1.extractTar)(archivePath, compressionMethod);
             core.info("Cache restored successfully");
-            return gcsPath;
+            return matchedKey;
         }
         catch (error) {
             core.warning(`Failed to restore: ${error.message}`);
@@ -92662,7 +92668,7 @@ function findFileOnGCS(storage, bucket, pathPrefix, keys, compressionMethod) {
             const gcsPath = getGCSPath(pathPrefix, key, compressionMethod);
             if (yield checkFileExists(storage, bucket, gcsPath)) {
                 core.info(`Found file on bucket: ${bucket} with key: ${gcsPath}`);
-                return gcsPath;
+                return { key, path: gcsPath };
             }
         }
         return undefined;
diff --git a/dist/save/index.js b/dist/save/index.js
index 75583a2..f75a284 100644
--- a/dist/save/index.js
+++ b/dist/save/index.js
@@ -92572,15 +92572,21 @@ function restoreFromGCS(_paths_1, primaryKey_1) {
         const archiveFolder = yield utils.createTempDirectory();
         const archivePath = path.join(archiveFolder, utils.getCacheFileName(compressionMethod));
         const keys = [primaryKey, ...restoreKeys];
-        const gcsPath = yield findFileOnGCS(storage, bucket, pathPrefix, keys, compressionMethod);
-        if (!gcsPath) {
+        const match = yield findFileOnGCS(storage, bucket, pathPrefix, keys, compressionMethod);
+        if (!match) {
             core.info(`No matching cache found`);
             return undefined;
         }
+        // Preserve the @actions/cache contract: return the matched cache KEY
+        // (primaryKey or a restoreKey), not the GCS object path. The caller
+        // (restoreImpl) compares the return value against primaryKey to set the
+        // `cache-hit` output — returning the gcs path makes `cache-hit` always
+        // false, re-triggering downstream install/build steps that gate on it.
+        const { key: matchedKey, path: gcsPath } = match;
         // If lookup only, just return the key
         if (options === null || options === void 0 ? void 0 : options.lookupOnly) {
-            core.info(`Cache found in GCS with key: ${gcsPath}`);
-            return gcsPath;
+            core.info(`Cache found in GCS with key: ${matchedKey}`);
+            return matchedKey;
         }
         try {
             core.info(`Downloading from GCS: ${bucket}/${gcsPath}`);
@@ -92593,7 +92599,7 @@ function restoreFromGCS(_paths_1, primaryKey_1) {
             core.info(`Cache Size: ~${Math.round(archiveFileSize / (1024 * 1024))} MB (${archiveFileSize} B)`);
             yield (0, tar_1.extractTar)(archivePath, compressionMethod);
             core.info("Cache restored successfully");
-            return gcsPath;
+            return matchedKey;
         }
         catch (error) {
             core.warning(`Failed to restore: ${error.message}`);
@@ -92662,7 +92668,7 @@ function findFileOnGCS(storage, bucket, pathPrefix, keys, compressionMethod) {
             const gcsPath = getGCSPath(pathPrefix, key, compressionMethod);
             if (yield checkFileExists(storage, bucket, gcsPath)) {
                 core.info(`Found file on bucket: ${bucket} with key: ${gcsPath}`);
-                return gcsPath;
+                return { key, path: gcsPath };
             }
         }
         return undefined;
diff --git a/src/utils/gcsCache.ts b/src/utils/gcsCache.ts
index 041335b..e631fdd 100644
--- a/src/utils/gcsCache.ts
+++ b/src/utils/gcsCache.ts
@@ -128,7 +128,7 @@ async function restoreFromGCS(
     );
 
     const keys = [primaryKey, ...restoreKeys];
-    const gcsPath = await findFileOnGCS(
+    const match = await findFileOnGCS(
         storage,
         bucket,
         pathPrefix,
@@ -136,15 +136,22 @@ async function restoreFromGCS(
         compressionMethod
     );
 
-    if (!gcsPath) {
+    if (!match) {
         core.info(`No matching cache found`);
         return undefined;
     }
 
+    // Preserve the @actions/cache contract: return the matched cache KEY
+    // (primaryKey or a restoreKey), not the GCS object path. The caller
+    // (restoreImpl) compares the return value against primaryKey to set the
+    // `cache-hit` output — returning the gcs path makes `cache-hit` always
+    // false, re-triggering downstream install/build steps that gate on it.
+    const { key: matchedKey, path: gcsPath } = match;
+
     // If lookup only, just return the key
     if (options?.lookupOnly) {
-        core.info(`Cache found in GCS with key: ${gcsPath}`);
-        return gcsPath;
+        core.info(`Cache found in GCS with key: ${matchedKey}`);
+        return matchedKey;
     }
 
     try {
@@ -166,7 +173,7 @@ async function restoreFromGCS(
         await extractTar(archivePath, compressionMethod);
         core.info("Cache restored successfully");
 
-        return gcsPath;
+        return matchedKey;
     } catch (error) {
         core.warning(`Failed to restore: ${(error as Error).message}`);
     } finally {
@@ -254,12 +261,12 @@ async function findFileOnGCS(
     pathPrefix: string,
     keys: string[],
     compressionMethod: CompressionMethod
-): Promise<string | undefined> {
+): Promise<{ key: string; path: string } | undefined> {
     for (const key of keys) {
         const gcsPath = getGCSPath(pathPrefix, key, compressionMethod);
         if (await checkFileExists(storage, bucket, gcsPath)) {
             core.info(`Found file on bucket: ${bucket} with key: ${gcsPath}`);
-            return gcsPath;
+            return { key, path: gcsPath };
         }
     }
     return undefined;