diff --git a/src/__tests__/definitions/invalid-cfn-definition-substitutions.json b/src/__tests__/definitions/invalid-cfn-definition-substitutions.json
new file mode 100644
index 0000000..9bdd23b
--- /dev/null
+++ b/src/__tests__/definitions/invalid-cfn-definition-substitutions.json
@@ -0,0 +1,18 @@
+{
+  "Comment": "https://states-language.net/spec.html#parameters",
+  "StartAt": "X",
+  "States": {
+    "X": {
+      "Type": "Task",
+      "Resource": "${lambdaArn",
+      "Parameters": {
+        "flagged": true,
+        "parts": {
+          "first.$": "$.vals[0]",
+          "last3.$": "$.vals[3:]"
+        }
+      },
+      "End": true
+    }
+  }
+}
diff --git a/src/__tests__/definitions/valid-cfn-definition-substitutions.json b/src/__tests__/definitions/valid-cfn-definition-substitutions.json
new file mode 100644
index 0000000..7bc55cb
--- /dev/null
+++ b/src/__tests__/definitions/valid-cfn-definition-substitutions.json
@@ -0,0 +1,18 @@
+{
+  "Comment": "https://states-language.net/spec.html#parameters",
+  "StartAt": "X",
+  "States": {
+    "X": {
+      "Type": "Task",
+      "Resource": "${lambdaArn}",
+      "Parameters": {
+        "flagged": true,
+        "parts": {
+          "first.$": "$.vals[0]",
+          "last3.$": "$.vals[3:]"
+        }
+      },
+      "End": true
+    }
+  }
+}
diff --git a/src/schemas/task.json b/src/schemas/task.json
index e60fecc..fa03445 100644
--- a/src/schemas/task.json
+++ b/src/schemas/task.json
@@ -25,7 +25,7 @@
     "Resource": {
       "oneOf": [{
         "type": "string",
-        "pattern": "^arn:aws:([a-z]|-)+:([a-z]|[0-9]|-)*:[0-9]*:([a-z]|-)+:[a-zA-Z0-9-_.]+(:(\\$LATEST|[a-zA-Z0-9-_]+))?$"
+        "pattern": "^(arn:aws:([a-z]|-)+:([a-z]|[0-9]|-)*:[0-9]*:([a-z]|-)+:[a-zA-Z0-9-_.]+(:(\\$LATEST|[a-zA-Z0-9-_]+))?$)|(\\${.*\\})"
       }, {
         "type": "object"
       }]