diff --git a/packages/compass-indexes/src/components/search-indexes-modals/base-search-index-modal.spec.tsx b/packages/compass-indexes/src/components/search-indexes-modals/base-search-index-modal.spec.tsx
index 3d0ed11e56f..164ad403081 100644
--- a/packages/compass-indexes/src/components/search-indexes-modals/base-search-index-modal.spec.tsx
+++ b/packages/compass-indexes/src/components/search-indexes-modals/base-search-index-modal.spec.tsx
@@ -1,4 +1,7 @@
-import { ATLAS_SEARCH_TEMPLATES } from '@mongodb-js/mongodb-constants';
+import {
+  ATLAS_SEARCH_TEMPLATES,
+  ATLAS_VECTOR_SEARCH_TEMPLATE,
+} from '@mongodb-js/mongodb-constants';
 import { expect } from 'chai';
 import { BaseSearchIndexModal } from './base-search-index-modal';
 import sinon from 'sinon';
@@ -7,7 +10,10 @@ import { render, screen, cleanup, waitFor } from '@testing-library/react';
 import userEvent from '@testing-library/user-event';
 
 import React from 'react';
-import { getCodemirrorEditorValue } from '@mongodb-js/compass-editor';
+import {
+  getCodemirrorEditorValue,
+  setCodemirrorEditorValue,
+} from '@mongodb-js/compass-editor';
 
 function normalizedTemplateNamed(name: string) {
   const snippet =
@@ -19,6 +25,20 @@ function normalizedTemplateNamed(name: string) {
   return snippet.replace(/\${\d+:([^}]+)}/gm, '$1');
 }
 
+const VALID_ATLAS_SEARCH_INDEX_DEFINITION = {
+  fields: [
+    {
+      type: 'vector',
+      path: 'pineapple',
+      numDimensions: 1000,
+      similarity: 'cosine',
+    },
+  ],
+};
+const VALID_ATLAS_SEARCH_INDEX_DEFINITION_STRING = JSON.stringify(
+  VALID_ATLAS_SEARCH_INDEX_DEFINITION
+);
+
 function renderBaseSearchIndexModal(
   props?: Partial<React.ComponentProps<typeof BaseSearchIndexModal>>
 ) {
@@ -113,7 +133,7 @@ describe('Base Search Index Modal', function () {
         });
       });
 
-      it('submits the modal with the correct type on create search index', function () {
+      it('submits the modal with the correct type on create search index', async function () {
         userEvent.click(
           screen.getByTestId('search-index-type-vectorSearch-button'),
           undefined,
@@ -122,15 +142,73 @@ describe('Base Search Index Modal', function () {
             skipPointerEventsCheck: true,
           }
         );
+        await waitFor(() => {
+          const indexDef = getCodemirrorEditorValue(
+            'definition-of-search-index'
+          );
+          expect(indexDef).to.equal(ATLAS_VECTOR_SEARCH_TEMPLATE.snippet);
+        });
+
+        // Set the value to something where the create index button is enabled.
+        await setCodemirrorEditorValue(
+          'definition-of-search-index',
+          VALID_ATLAS_SEARCH_INDEX_DEFINITION_STRING
+        );
         userEvent.click(
           screen.getByRole('button', { name: 'Create Search Index' })
         );
         expect(onSubmitSpy).to.have.been.calledOnceWithExactly({
           name: 'default',
-          definition: {},
+          definition: VALID_ATLAS_SEARCH_INDEX_DEFINITION,
           type: 'vectorSearch',
         });
       });
+
+      it('resets the template on type switch', async function () {
+        userEvent.click(
+          screen.getByTestId('search-index-type-vectorSearch-button'),
+          undefined,
+          {
+            // leafygreen adds pointer-events: none on actually clickable elements
+            skipPointerEventsCheck: true,
+          }
+        );
+
+        await waitFor(() => {
+          const indexDef = getCodemirrorEditorValue(
+            'definition-of-search-index'
+          );
+          expect(indexDef).to.equal(ATLAS_VECTOR_SEARCH_TEMPLATE.snippet);
+        });
+
+        userEvent.click(
+          screen.getByTestId('search-index-type-search-button'),
+          undefined,
+          {
+            // leafygreen adds pointer-events: none on actually clickable elements
+            skipPointerEventsCheck: true,
+          }
+        );
+
+        await waitFor(() => {
+          const indexDef = getCodemirrorEditorValue(
+            'definition-of-search-index'
+          );
+          expect(indexDef).to.equal(
+            normalizedTemplateNamed('Dynamic field mappings')
+          );
+        });
+        // Ensure the state is updated when the ace snippet changes.
+        await new Promise((resolve) => setTimeout(resolve, 10));
+        userEvent.click(
+          screen.getByRole('button', { name: 'Create Search Index' })
+        );
+        expect(onSubmitSpy).to.have.been.calledOnceWithExactly({
+          name: 'default',
+          definition: { mappings: { dynamic: true } },
+          type: 'search',
+        });
+      });
     });
 
     describe('templates', function () {
diff --git a/packages/compass-indexes/src/components/search-indexes-modals/base-search-index-modal.tsx b/packages/compass-indexes/src/components/search-indexes-modals/base-search-index-modal.tsx
index 53b46ab4e57..c0d38f6195b 100644
--- a/packages/compass-indexes/src/components/search-indexes-modals/base-search-index-modal.tsx
+++ b/packages/compass-indexes/src/components/search-indexes-modals/base-search-index-modal.tsx
@@ -37,6 +37,7 @@ import type { Document } from 'mongodb';
 import { useTrackOnChange } from '@mongodb-js/compass-logging/provider';
 import { SearchIndexTemplateDropdown } from '../search-index-template-dropdown';
 import {
+  ATLAS_SEARCH_TEMPLATES,
   ATLAS_VECTOR_SEARCH_TEMPLATE,
   type SearchTemplate,
 } from '@mongodb-js/mongodb-constants';
@@ -201,6 +202,7 @@ export const BaseSearchIndexModal: React.FunctionComponent<
 
   useEffect(() => {
     if (isModalOpen) {
+      setSearchIndexType('search');
       setIndexName(initialIndexName);
       setIndexDefinition(initialIndexDefinition);
       setParsingError(undefined);
@@ -261,12 +263,14 @@ export const BaseSearchIndexModal: React.FunctionComponent<
 
       // Set the template.
       if (value === 'vectorSearch') {
+        setIndexDefinition(ATLAS_VECTOR_SEARCH_TEMPLATE.snippet);
         onChangeTemplate(ATLAS_VECTOR_SEARCH_TEMPLATE);
       } else {
-        onSearchIndexDefinitionChanged(DEFAULT_INDEX_DEFINITION);
+        setIndexDefinition(ATLAS_SEARCH_TEMPLATES[0].snippet);
+        onChangeTemplate(ATLAS_SEARCH_TEMPLATES[0]);
       }
     },
-    [setSearchIndexType, onChangeTemplate, onSearchIndexDefinitionChanged]
+    [setSearchIndexType, onChangeTemplate, setIndexDefinition]
   );
 
   const fields = useAutocompleteFields(namespace);
@@ -421,7 +425,7 @@ export const BaseSearchIndexModal: React.FunctionComponent<
           data-testid="search-index-submit-button"
           variant="primary"
           onClick={onSubmitIndex}
-          disabled={isBusy}
+          disabled={isBusy || !!parsingError}
         >
           {mode === 'create' ? 'Create Search Index' : 'Save'}
         </Button>