diff --git a/packages/core/src/tools/create-storekey-tool.js b/packages/core/src/tools/create-storekey-tool.js
index 17240ef0c..372ca03c8 100644
--- a/packages/core/src/tools/create-storekey-tool.js
+++ b/packages/core/src/tools/create-storekey-tool.js
@@ -14,11 +14,18 @@ const createStoreKeyTool = (input) => {
 
       return rpc('get_cursor');
     },
+
     set: (cursor) => {
       if (!rpc) {
         return ZapierPromise.reject(new Error('rpc is not available'));
       }
 
+      if (!_.isString(cursor)) {
+        return ZapierPromise.reject(
+          new TypeError('cursor value must be a string')
+        );
+      }
+
       return rpc('set_cursor', cursor);
     },
   };
diff --git a/packages/core/test/tools/create-storekey-tools.js b/packages/core/test/tools/create-storekey-tools.js
new file mode 100644
index 000000000..ff9123f24
--- /dev/null
+++ b/packages/core/test/tools/create-storekey-tools.js
@@ -0,0 +1,41 @@
+'use strict';
+
+const should = require('should');
+
+const { makeRpc, mockRpcCall } = require('./mocky');
+const createStoreKeyTool = require('../../src/tools/create-storekey-tool');
+
+describe('storekey (cursor): get, set', () => {
+  const rpc = makeRpc();
+  const cursor = createStoreKeyTool({ _zapier: { rpc } });
+
+  it('storekey (cursor) get: should return the cursor value given a key', async () => {
+    const expected = 64;
+    mockRpcCall(expected);
+
+    const result = await cursor.get('existing-key');
+    should(result).eql(expected);
+  });
+
+  it('storekey (cursor) set: should raise TypeError on non-string value', async () => {
+    await should(cursor.set(64)).rejectedWith(TypeError, {
+      message: 'cursor value must be a string',
+    });
+
+    await should(cursor.set(null)).rejectedWith(TypeError, {
+      message: 'cursor value must be a string',
+    });
+
+    await should(cursor.set(undefined)).rejectedWith(TypeError, {
+      message: 'cursor value must be a string',
+    });
+  });
+
+  it('storekey (cursor) set: should set a cursor entry', async () => {
+    const expected = 'ok';
+    mockRpcCall(expected);
+
+    const result1 = await cursor.set('test-key');
+    should(result1).eql(expected);
+  });
+});