diff --git a/x-pack/plugin/runtime-fields/src/main/java/org/elasticsearch/xpack/runtimefields/mapper/AbstractScriptMappedFieldType.java b/x-pack/plugin/runtime-fields/src/main/java/org/elasticsearch/xpack/runtimefields/mapper/AbstractScriptMappedFieldType.java
index 71340ebc0e3d0..935b4f6ff49e7 100644
--- a/x-pack/plugin/runtime-fields/src/main/java/org/elasticsearch/xpack/runtimefields/mapper/AbstractScriptMappedFieldType.java
+++ b/x-pack/plugin/runtime-fields/src/main/java/org/elasticsearch/xpack/runtimefields/mapper/AbstractScriptMappedFieldType.java
@@ -34,7 +34,7 @@ abstract class AbstractScriptMappedFieldType extends MappedFieldType {
 
     void mapperXContentBody(XContentBuilder builder, Params params) throws IOException {
         builder.field("runtime_type", runtimeType());
-        builder.field("script", script.getIdOrCode()); // TODO For some reason this doesn't allow us to do the full xcontent of the script.
+        builder.field("script", script, params);
     }
 
     @Override
diff --git a/x-pack/plugin/src/test/resources/rest-api-spec/test/runtime_fields/10_keyword.yml b/x-pack/plugin/src/test/resources/rest-api-spec/test/runtime_fields/10_keyword.yml
index 87d51f70923ba..f9b6d89da3f90 100644
--- a/x-pack/plugin/src/test/resources/rest-api-spec/test/runtime_fields/10_keyword.yml
+++ b/x-pack/plugin/src/test/resources/rest-api-spec/test/runtime_fields/10_keyword.yml
@@ -20,7 +20,8 @@ setup:
               day_of_week:
                 type: script
                 runtime_type: keyword
-                script: value(doc['timestamp'].value.dayOfWeekEnum.getDisplayName(TextStyle.FULL, Locale.ROOT))
+                script: |
+                  value(doc['timestamp'].value.dayOfWeekEnum.getDisplayName(TextStyle.FULL, Locale.ROOT))
               days_starting_with_t:
                 type: script
                 runtime_type: keyword
@@ -30,6 +31,16 @@ setup:
                       value(dow);
                     }
                   }
+              prefixed_node:
+                type: script
+                runtime_type: keyword
+                script:
+                  source: |
+                    for (String node : doc['node']) {
+                      value(params.prefix + node);
+                    }
+                  params:
+                    prefix: node_
 
   - do:
       bulk:
@@ -49,6 +60,37 @@ setup:
           {"index":{}}
           {"timestamp": 1516297294000, "temperature": 202, "voltage": 4.0, "node": "c"}
 
+---
+"get mapping":
+  - do:
+      indices.get_mapping:
+        index: sensor
+  - match: {sensor.mappings.properties.day_of_week.type: script }
+  - match: {sensor.mappings.properties.day_of_week.runtime_type: keyword }
+  - match:
+      sensor.mappings.properties.day_of_week.script.source: |
+        value(doc['timestamp'].value.dayOfWeekEnum.getDisplayName(TextStyle.FULL, Locale.ROOT))
+  - match: {sensor.mappings.properties.day_of_week.script.lang: painless }
+  - match: {sensor.mappings.properties.days_starting_with_t.type: script }
+  - match: {sensor.mappings.properties.days_starting_with_t.runtime_type: keyword }
+  - match:
+      sensor.mappings.properties.days_starting_with_t.script.source: |
+        for (String dow: doc['day_of_week']) {
+          if (dow.startsWith('T')) {
+            value(dow);
+          }
+        }
+  - match: {sensor.mappings.properties.days_starting_with_t.script.lang: painless }
+  - match: {sensor.mappings.properties.prefixed_node.type: script }
+  - match: {sensor.mappings.properties.prefixed_node.runtime_type: keyword }
+  - match:
+      sensor.mappings.properties.prefixed_node.script.source: |
+        for (String node : doc['node']) {
+          value(params.prefix + node);
+        }
+  - match: {sensor.mappings.properties.prefixed_node.script.params: {prefix: node_} }
+  - match: {sensor.mappings.properties.prefixed_node.script.lang: painless }
+
 ---
 "docvalue_fields":
   - do:
@@ -56,9 +98,11 @@ setup:
         index: sensor
         body:
           sort: timestamp
-          docvalue_fields: [day_of_week]
+          docvalue_fields: [day_of_week, days_starting_with_t, prefixed_node]
   - match: {hits.total.value: 6}
   - match: {hits.hits.0.fields.day_of_week: [Thursday] }
+  - match: {hits.hits.0.fields.days_starting_with_t: [Thursday] }
+  - match: {hits.hits.0.fields.prefixed_node: [node_c] }
 
 ---
 "terms agg":
diff --git a/x-pack/plugin/src/test/resources/rest-api-spec/test/runtime_fields/20_long.yml b/x-pack/plugin/src/test/resources/rest-api-spec/test/runtime_fields/20_long.yml
index d5f716b362630..9029513439848 100644
--- a/x-pack/plugin/src/test/resources/rest-api-spec/test/runtime_fields/20_long.yml
+++ b/x-pack/plugin/src/test/resources/rest-api-spec/test/runtime_fields/20_long.yml
@@ -20,10 +20,13 @@ setup:
               voltage_times_ten:
                 type: script
                 runtime_type: long
-                script: |
-                  for (double v : doc['voltage']) {
-                    value((long)(v * 10));
-                  }
+                script:
+                  source: |
+                    for (double v : doc['voltage']) {
+                      value((long)(v * params.multiplier));
+                    }
+                  params:
+                    multiplier: 10
               even_voltage_times_ten:
                 type: script
                 runtime_type: long
@@ -52,6 +55,31 @@ setup:
           {"index":{}}
           {"timestamp": 1516297294000, "temperature": 202, "voltage": 4.0, "node": "c"}
 
+---
+"get mapping":
+  - do:
+      indices.get_mapping:
+        index: sensor
+  - match: {sensor.mappings.properties.voltage_times_ten.type: script }
+  - match: {sensor.mappings.properties.voltage_times_ten.runtime_type: long }
+  - match:
+      sensor.mappings.properties.voltage_times_ten.script.source: |
+        for (double v : doc['voltage']) {
+          value((long)(v * params.multiplier));
+        }
+  - match: {sensor.mappings.properties.voltage_times_ten.script.params: {multiplier: 10} }
+  - match: {sensor.mappings.properties.voltage_times_ten.script.lang: painless }
+  - match: {sensor.mappings.properties.even_voltage_times_ten.type: script }
+  - match: {sensor.mappings.properties.even_voltage_times_ten.runtime_type: long }
+  - match:
+      sensor.mappings.properties.even_voltage_times_ten.script.source: |
+        for (long tenV: doc['voltage_times_ten']) {
+          if (tenV % 2 == 0) {
+            value(tenV);
+          }
+        }
+  - match: {sensor.mappings.properties.even_voltage_times_ten.script.lang: painless }
+
 ---
 "docvalue_fields":
   - do: