diff --git a/src/legacy/core_plugins/interpreter/public/functions/visualization.js b/src/legacy/core_plugins/interpreter/public/functions/visualization.js
index 14831f7ff6e9b..649abd70de5f6 100644
--- a/src/legacy/core_plugins/interpreter/public/functions/visualization.js
+++ b/src/legacy/core_plugins/interpreter/public/functions/visualization.js
@@ -116,17 +116,21 @@ export const visualization = () => ({
       if (context.columns) {
         // assign schemas to aggConfigs
         context.columns.forEach(column => {
-          column.aggConfig.aggConfigs.schemas = visType.schemas.all;
+          if (column.aggConfig) {
+            column.aggConfig.aggConfigs.schemas = visType.schemas.all;
+          }
         });
 
         Object.keys(schemas).forEach(key => {
           schemas[key].forEach(i => {
-            context.columns[i].aggConfig.schema = key;
+            if (context.columns[i] && context.columns[i].aggConfig) {
+              context.columns[i].aggConfig.schema = key;
+            }
           });
         });
       }
 
-      context = await responseHandler(context);
+      context = await responseHandler(context, visConfigParams.dimensions);
     }
 
     return {
diff --git a/src/legacy/ui/public/visualize/loader/pipeline_helpers/__snapshots__/build_pipeline.test.js.snap b/src/legacy/ui/public/visualize/loader/pipeline_helpers/__snapshots__/build_pipeline.test.js.snap
index ee4f3354cc9ed..f06a7959347f3 100644
--- a/src/legacy/ui/public/visualize/loader/pipeline_helpers/__snapshots__/build_pipeline.test.js.snap
+++ b/src/legacy/ui/public/visualize/loader/pipeline_helpers/__snapshots__/build_pipeline.test.js.snap
@@ -1,5 +1,7 @@
 // Jest Snapshot v1, https://goo.gl/fbAQLP
 
+exports[`visualize loader pipeline helpers: build pipeline buildPipeline calls toExpression on vis_type if it exists 1`] = `"kibana | kibana_context | testing custom expressions"`;
+
 exports[`visualize loader pipeline helpers: build pipeline buildPipelineVisFunction handles input_control_vis function 1`] = `"input_control_vis visConfig='{\\"some\\":\\"nested\\",\\"data\\":{\\"here\\":true}}' "`;
 
 exports[`visualize loader pipeline helpers: build pipeline buildPipelineVisFunction handles markdown function 1`] = `"markdownvis '## hello _markdown_'  fontSize=12 openLinksInNewTab=true "`;
diff --git a/src/legacy/ui/public/visualize/loader/pipeline_helpers/build_pipeline.test.js b/src/legacy/ui/public/visualize/loader/pipeline_helpers/build_pipeline.test.js
index a38b567b2f589..e02286c346e39 100644
--- a/src/legacy/ui/public/visualize/loader/pipeline_helpers/build_pipeline.test.js
+++ b/src/legacy/ui/public/visualize/loader/pipeline_helpers/build_pipeline.test.js
@@ -17,7 +17,7 @@
  * under the License.
  */
 
-import { prepareJson, prepareString, buildPipelineVisFunction } from './build_pipeline';
+import { prepareJson, prepareString, buildPipelineVisFunction, buildPipeline } from './build_pipeline';
 
 jest.mock('ui/agg_types/buckets/date_histogram', () => ({}));
 
@@ -224,4 +224,25 @@ describe('visualize loader pipeline helpers: build pipeline', () => {
       expect(actual).toMatchSnapshot();
     });
   });
+
+  describe('buildPipeline', () => {
+    it('calls toExpression on vis_type if it exists', async () => {
+      const vis = {
+        getCurrentState: () => {},
+        getUiState: () => null,
+        isHierarchical: () => false,
+        aggs: {
+          getResponseAggs: () => [],
+        },
+        type: {
+          toExpression: () => 'testing custom expressions',
+        }
+      };
+      const searchSource = {
+        getField: () => null,
+      };
+      const expression = await buildPipeline(vis, { searchSource });
+      expect(expression).toMatchSnapshot();
+    });
+  });
 });
diff --git a/src/legacy/ui/public/visualize/loader/pipeline_helpers/build_pipeline.ts b/src/legacy/ui/public/visualize/loader/pipeline_helpers/build_pipeline.ts
index 1205632641ab6..8e8c9ef737be0 100644
--- a/src/legacy/ui/public/visualize/loader/pipeline_helpers/build_pipeline.ts
+++ b/src/legacy/ui/public/visualize/loader/pipeline_helpers/build_pipeline.ts
@@ -464,9 +464,13 @@ export const buildPipeline = async (
     visConfig.dimensions = await buildVislibDimensions(vis, params);
 
     pipeline += `vislib ${prepareJson('visConfig', visState.params)}`;
+  } else if (vis.type.toExpression) {
+    pipeline += await vis.type.toExpression(vis, params);
   } else {
+    const visConfig = visState.params;
+    visConfig.dimensions = schemas;
     pipeline += `visualization type='${vis.type.name}'
-    ${prepareJson('visConfig', visState.params)}
+    ${prepareJson('visConfig', visConfig)}
     metricsAtAllLevels=${vis.isHierarchical()}
     partialRows=${vis.type.requiresPartialRows || vis.params.showPartialRows || false} `;
     if (indexPattern) {