diff --git a/src/editors/EditorContainer.tsx b/src/editors/EditorContainer.tsx
index fc6fa417c1..c5b2d5ec89 100644
--- a/src/editors/EditorContainer.tsx
+++ b/src/editors/EditorContainer.tsx
@@ -7,32 +7,29 @@ import EditorPage from './EditorPage';
 interface Props {
   /** Course ID or Library ID */
   learningContextId: string;
-  /** Event handler for when user cancels out of the editor page */
+  /** Event handler sometimes called when user cancels out of the editor page */
   onClose?: () => void;
-  /** Event handler called after when user saves their changes using an editor */
-  afterSave?: () => (newData: Record<string, any>) => void;
+  /**
+   * Event handler called after when user saves their changes using an editor
+   * and sometimes called when user cancels the editor, instead of onClose.
+   * If changes are saved, newData will be present, and if it was cancellation,
+   * newData will be undefined.
+   * TODO: clean this up so there are separate onCancel and onSave callbacks,
+   * and they are used consistently instead of this mess.
+   */
+  returnFunction?: () => (newData: Record<string, any> | undefined) => void;
 }
 
 const EditorContainer: React.FC<Props> = ({
   learningContextId,
   onClose,
-  afterSave,
+  returnFunction,
 }) => {
   const { blockType, blockId } = useParams();
   if (blockType === undefined || blockId === undefined) {
     // istanbul ignore next - This shouldn't be possible; it's just here to satisfy the type checker.
     return <div>Error: missing URL parameters</div>;
   }
-  if (!!onClose !== !!afterSave) {
-    /* istanbul ignore next */
-    throw new Error('You must specify both onClose and afterSave or neither.');
-    // These parameters are a bit messy so I'm trying to help make it more
-    // consistent here. For example, if you specify onClose, then returnFunction
-    // is only called if the save is successful. But if you leave onClose
-    // undefined, then returnFunction is called in either case, and with
-    // different arguments. The underlying EditorPage should be refactored to
-    // have more clear events like onCancel and onSaveSuccess
-  }
   return (
     <div className="editor-page">
       <EditorPage
@@ -42,7 +39,7 @@ const EditorContainer: React.FC<Props> = ({
         studioEndpointUrl={getConfig().STUDIO_BASE_URL}
         lmsEndpointUrl={getConfig().LMS_BASE_URL}
         onClose={onClose}
-        returnFunction={afterSave}
+        returnFunction={returnFunction}
       />
     </div>
   );
diff --git a/src/editors/data/constants/requests.js b/src/editors/data/constants/requests.ts
similarity index 97%
rename from src/editors/data/constants/requests.js
rename to src/editors/data/constants/requests.ts
index ec736f27ea..e12905d588 100644
--- a/src/editors/data/constants/requests.js
+++ b/src/editors/data/constants/requests.ts
@@ -5,7 +5,7 @@ export const RequestStates = StrictDict({
   pending: 'pending',
   completed: 'completed',
   failed: 'failed',
-});
+} as const);
 
 export const RequestKeys = StrictDict({
   fetchVideos: 'fetchVideos',
@@ -27,4 +27,4 @@ export const RequestKeys = StrictDict({
   uploadAsset: 'uploadAsset',
   fetchAdvancedSettings: 'fetchAdvancedSettings',
   fetchVideoFeatures: 'fetchVideoFeatures',
-});
+} as const);
diff --git a/src/editors/data/redux/app/selectors.js b/src/editors/data/redux/app/selectors.js
index 43e7d6861a..91d880a2d6 100644
--- a/src/editors/data/redux/app/selectors.js
+++ b/src/editors/data/redux/app/selectors.js
@@ -1,5 +1,6 @@
 import { createSelector } from 'reselect';
 import { blockTypes } from '../../constants/app';
+import { isLibraryV1Key } from '../../../../generic/key-utils';
 import * as urls from '../../services/cms/urls';
 // This 'module' self-import hack enables mocking during tests.
 // See src/editors/decisions/0005-internal-editor-testability-decisions.md. The whole approach to how hooks are tested
@@ -46,7 +47,7 @@ export const isLibrary = createSelector(
     module.simpleSelectors.blockId,
   ],
   (learningContextId, blockId) => {
-    if (learningContextId && learningContextId.startsWith('library-v1')) {
+    if (isLibraryV1Key(learningContextId)) {
       return true;
     }
     if (blockId && blockId.startsWith('lb:')) {
diff --git a/src/editors/data/redux/thunkActions/app.js b/src/editors/data/redux/thunkActions/app.js
index 2e210bb80d..478ef4240c 100644
--- a/src/editors/data/redux/thunkActions/app.js
+++ b/src/editors/data/redux/thunkActions/app.js
@@ -1,4 +1,5 @@
 import { StrictDict, camelizeKeys } from '../../../utils';
+import { isLibraryKey } from '../../../../generic/key-utils';
 import * as requests from './requests';
 // This 'module' self-import hack enables mocking during tests.
 // See src/editors/decisions/0005-internal-editor-testability-decisions.md. The whole approach to how hooks are tested
@@ -102,7 +103,7 @@ export const initialize = (data) => (dispatch) => {
       dispatch(module.fetchCourseDetails());
       break;
     case 'html':
-      if (data.learningContextId?.startsWith('lib:')) {
+      if (isLibraryKey(data.learningContextId)) {
         // eslint-disable-next-line no-console
         console.log('Not fetching image assets - not implemented yet for content libraries.');
       } else {
diff --git a/src/editors/data/redux/thunkActions/problem.test.js b/src/editors/data/redux/thunkActions/problem.test.ts
similarity index 96%
rename from src/editors/data/redux/thunkActions/problem.test.js
rename to src/editors/data/redux/thunkActions/problem.test.ts
index 828547b5b4..873ad0e8a9 100644
--- a/src/editors/data/redux/thunkActions/problem.test.js
+++ b/src/editors/data/redux/thunkActions/problem.test.ts
@@ -45,6 +45,9 @@ describe('problem thunkActions', () => {
     getState = jest.fn(() => ({
       problem: {
       },
+      app: {
+        learningContextId: 'course-v1:org+course+run',
+      },
     }));
   });
 
@@ -52,7 +55,7 @@ describe('problem thunkActions', () => {
     jest.restoreAllMocks();
   });
   test('initializeProblem visual Problem :', () => {
-    initializeProblem(blockValue)(dispatch);
+    initializeProblem(blockValue)(dispatch, getState);
     expect(dispatch).toHaveBeenCalled();
   });
   test('switchToAdvancedEditor visual Problem', () => {
diff --git a/src/editors/data/redux/thunkActions/problem.js b/src/editors/data/redux/thunkActions/problem.ts
similarity index 72%
rename from src/editors/data/redux/thunkActions/problem.js
rename to src/editors/data/redux/thunkActions/problem.ts
index 62de4f44a9..79916195e4 100644
--- a/src/editors/data/redux/thunkActions/problem.js
+++ b/src/editors/data/redux/thunkActions/problem.ts
@@ -1,16 +1,20 @@
 import _ from 'lodash';
 import { actions as problemActions } from '../problem';
+import { actions as requestActions } from '../requests';
+import { selectors as appSelectors } from '../app';
 import * as requests from './requests';
+import { isLibraryKey } from '../../../../generic/key-utils';
 import { OLXParser } from '../../../containers/ProblemEditor/data/OLXParser';
 import { parseSettings } from '../../../containers/ProblemEditor/data/SettingsParser';
 import { ProblemTypeKeys } from '../../constants/problem';
 import ReactStateOLXParser from '../../../containers/ProblemEditor/data/ReactStateOLXParser';
-import { blankProblemOLX } from '../../../containers/ProblemEditor/data/mockData/olxTestData';
 import { camelizeKeys } from '../../../utils';
 import { fetchEditorContent } from '../../../containers/ProblemEditor/components/EditProblemView/hooks';
+import { RequestKeys } from '../../constants/requests';
 
 // Similar to `import { actions, selectors } from '..';` but avoid circular imports:
-const actions = { problem: problemActions };
+const actions = { problem: problemActions, requests: requestActions };
+const selectors = { app: appSelectors };
 
 export const switchToAdvancedEditor = () => (dispatch, getState) => {
   const state = getState();
@@ -21,7 +25,7 @@ export const switchToAdvancedEditor = () => (dispatch, getState) => {
 };
 
 export const isBlankProblem = ({ rawOLX }) => {
-  if (rawOLX.replace(/\s/g, '') === blankProblemOLX.rawOLX) {
+  if (['<problem></problem>', '<problem/>'].includes(rawOLX.replace(/\s/g, ''))) {
     return true;
   }
   return false;
@@ -67,7 +71,7 @@ export const fetchAdvancedSettings = ({ rawOLX, rawSettings }) => (dispatch) =>
   dispatch(requests.fetchAdvancedSettings({
     onSuccess: (response) => {
       const defaultSettings = {};
-      Object.entries(response.data).forEach(([key, value]) => {
+      Object.entries(response.data as Record<string, any>).forEach(([key, value]) => {
         if (advancedProblemSettingKeys.includes(key)) {
           defaultSettings[key] = value.value;
         }
@@ -79,10 +83,20 @@ export const fetchAdvancedSettings = ({ rawOLX, rawSettings }) => (dispatch) =>
   }));
 };
 
-export const initializeProblem = (blockValue) => (dispatch) => {
+export const initializeProblem = (blockValue) => (dispatch, getState) => {
   const rawOLX = _.get(blockValue, 'data.data', {});
   const rawSettings = _.get(blockValue, 'data.metadata', {});
-  dispatch(fetchAdvancedSettings({ rawOLX, rawSettings }));
+  const learningContextId = selectors.app.learningContextId(getState());
+  if (isLibraryKey(learningContextId)) {
+    // Content libraries don't yet support defaults for fields like max_attempts, showanswer, etc.
+    // So proceed with loading the problem.
+    // Though first we need to fake the request or else the problem type selection UI won't display:
+    dispatch(actions.requests.completeRequest({ requestKey: RequestKeys.fetchAdvancedSettings, response: {} }));
+    dispatch(loadProblem({ rawOLX, rawSettings, defaultSettings: {} }));
+  } else {
+    // Load the defaults (for max_attempts, etc.) from the course's advanced settings, then proceed:
+    dispatch(fetchAdvancedSettings({ rawOLX, rawSettings }));
+  }
 };
 
 export default { initializeProblem, switchToAdvancedEditor, fetchAdvancedSettings };
diff --git a/src/editors/data/services/cms/api.test.js b/src/editors/data/services/cms/api.test.ts
similarity index 92%
rename from src/editors/data/services/cms/api.test.js
rename to src/editors/data/services/cms/api.test.ts
index 7abec953cc..656fb4db49 100644
--- a/src/editors/data/services/cms/api.test.js
+++ b/src/editors/data/services/cms/api.test.ts
@@ -1,19 +1,7 @@
-/* eslint-disable no-import-assign */
-import * as utils from '../../../utils';
 import * as api from './api';
-import * as mockApi from './mockApi';
 import * as urls from './urls';
 import { get, post, deleteObject } from './utils';
 
-jest.mock('../../../utils', () => {
-  const camelizeMap = (obj) => ({ ...obj, camelized: true });
-  return {
-    ...jest.requireActual('../../../utils'),
-    camelize: camelizeMap,
-    camelizeKeys: (list) => list.map(camelizeMap),
-  };
-});
-
 jest.mock('./urls', () => ({
   block: jest.fn().mockReturnValue('urls.block'),
   blockAncestor: jest.fn().mockReturnValue('urls.blockAncestor'),
@@ -40,8 +28,6 @@ jest.mock('./utils', () => ({
   deleteObject: jest.fn().mockName('deleteObject'),
 }));
 
-const { camelize } = utils;
-
 const { apiMethods } = api;
 
 const blockId = 'block-v1-coursev1:2uX@4345432';
@@ -200,7 +186,7 @@ describe('cms api', () => {
           licenseType: 'LiCeNsETYpe',
           licenseDetails: 'liCENSeDetAIls',
         };
-        const html5Sources = 'hTML5souRCES';
+        const html5Sources = ['hTML5souRCES'];
         const edxVideoId = 'eDXviDEOid';
         const youtubeId = 'yOUtUBeid';
         const license = 'LiCEnsE';
@@ -241,6 +227,7 @@ describe('cms api', () => {
         jest.restoreAllMocks();
       });
       test('throw error for invalid blockType', () => {
+        // @ts-expect-error because we're not passing 'blockId' or other parameters
         expect(() => { apiMethods.normalizeContent({ blockType: 'somethingINVALID' }); })
           .toThrow(TypeError);
       });
@@ -271,7 +258,7 @@ describe('cms api', () => {
     });
 
     describe('uploadAsset', () => {
-      const asset = { photo: 'dAta' };
+      const asset = new Blob(['data'], { type: 'image/jpeg' });
       it('should call post with urls.courseAssets and imgdata', () => {
         const mockFormdata = new FormData();
         mockFormdata.append('file', asset);
@@ -318,18 +305,17 @@ describe('cms api', () => {
         { id: ids[0], some: 'data' },
         { id: ids[1], other: 'data' },
         { id: ids[2], some: 'DATA' },
-        { id: ids[3], other: 'DATA' },
+        { id: ids[3], other_data: 'DATA' },
       ];
-      const oldLoadImage = api.loadImage;
-      api.loadImage = (imageData) => ({ loadImage: imageData });
+      const spy = jest.spyOn(api, 'loadImage').mockImplementation((imageData) => ({ loadImage: imageData }));
       const out = api.loadImages(testData);
       expect(out).toEqual({
-        [ids[0]]: api.loadImage(camelize(testData[0])),
-        [ids[1]]: api.loadImage(camelize(testData[1])),
-        [ids[2]]: api.loadImage(camelize(testData[2])),
-        [ids[3]]: api.loadImage(camelize(testData[3])),
+        [ids[0]]: api.loadImage(testData[0]),
+        [ids[1]]: api.loadImage(testData[1]),
+        [ids[2]]: api.loadImage(testData[2]),
+        [ids[3]]: api.loadImage({ id: ids[3], otherData: 'DATA' }), // Verify its 'other_data' key was camelized
       });
-      api.loadImage = oldLoadImage;
+      spy.mockClear();
     });
   });
   describe('uploadThumbnail', () => {
@@ -382,7 +368,7 @@ describe('cms api', () => {
       });
     });
     describe('uploadTranscript', () => {
-      const transcript = { transcript: 'dAta' };
+      const transcript = new Blob(['dAta']);
       it('should call post with urls.videoTranscripts and transcript data', () => {
         const mockFormdata = new FormData();
         mockFormdata.append('file', transcript);
@@ -606,31 +592,6 @@ describe('cms api', () => {
       expect(api.processLicense(licenseType, licenseDetails)).toEqual('all-rights-reserved');
     });
   });
-  describe('checkMockApi', () => {
-    const envTemp = process.env;
-    beforeEach(() => {
-      jest.resetModules();
-      process.env = { ...envTemp };
-    });
-    afterEach(() => {
-      process.env = envTemp;
-    });
-    describe('if REACT_APP_DEVGALLERY is true', () => {
-      it('should return the mockApi version of a call when it exists', () => {
-        process.env.REACT_APP_DEVGALLERY = true;
-        expect(api.checkMockApi('fetchBlockById')).toEqual(mockApi.fetchBlockById);
-      });
-      it('should return an empty mock when the call does not exist', () => {
-        process.env.REACT_APP_DEVGALLERY = true;
-        expect(api.checkMockApi('someRAnDomThINg')).toEqual(mockApi.emptyMock);
-      });
-    });
-    describe('if REACT_APP_DEVGALLERY is not true', () => {
-      it('should return the appropriate call', () => {
-        expect(api.checkMockApi('fetchBlockById')).toEqual(apiMethods.fetchBlockById);
-      });
-    });
-  });
   describe('fetchVideoFeatures', () => {
     it('should call get with url.videoFeatures', () => {
       const args = { studioEndpointUrl };
diff --git a/src/editors/data/services/cms/api.js b/src/editors/data/services/cms/api.ts
similarity index 83%
rename from src/editors/data/services/cms/api.js
rename to src/editors/data/services/cms/api.ts
index 7d732c15d4..bce827b5ae 100644
--- a/src/editors/data/services/cms/api.js
+++ b/src/editors/data/services/cms/api.ts
@@ -1,15 +1,11 @@
+import type { AxiosRequestConfig } from 'axios';
 import { camelizeKeys } from '../../../utils';
+import { isLibraryKey } from '../../../../generic/key-utils';
 import * as urls from './urls';
 import { get, post, deleteObject } from './utils';
-// This 'module' self-import hack enables mocking during tests.
-// See src/editors/decisions/0005-internal-editor-testability-decisions.md. The whole approach to how hooks are tested
-// should be re-thought and cleaned up to avoid this pattern.
-// eslint-disable-next-line import/no-self-import
-import * as module from './api';
-import * as mockApi from './mockApi';
 import { durationStringFromValue } from '../../../containers/VideoEditor/components/VideoSettingsModal/components/DurationWidget/hooks';
 
-const fetchByUnitIdOptions = {};
+const fetchByUnitIdOptions: AxiosRequestConfig = {};
 
 // For some reason, the local webpack-dev-server of library-authoring does not accept the normal Accept header.
 // This is a workaround only for that specific case; the idea is to only do this locally and only for library-authoring.
@@ -19,6 +15,87 @@ if (process.env.NODE_ENV === 'development' && process.env.MFE_NAME === 'frontend
   };
 }
 
+interface Pagination {
+  start: number;
+  end: number;
+  page: number;
+  pageSize: number;
+  totalCount: number;
+}
+
+interface AssetResponse {
+  assets: Record<string, string>[]; // In the raw response here, these are NOT camel-cased yet.
+}
+
+export const loadImage = (imageData) => ({
+  ...imageData,
+  dateAdded: new Date(imageData.dateAdded.replace(' at', '')).getTime(),
+});
+
+export const loadImages = (rawImages) => camelizeKeys(rawImages).reduce(
+  (obj, image) => ({ ...obj, [image.id]: loadImage(image) }),
+  {},
+);
+
+export const parseYoutubeId = (src: string): string | null => {
+  const youtubeRegex = /^((?:https?:)?\/\/)?((?:www|m)\.)?((?:youtube\.com|youtu.be))(\/(?:[\w-]+\?v=|embed\/|v\/)?)([\w-]+)(\S+)?$/;
+  const match = src.match(youtubeRegex);
+  if (!match) {
+    return null;
+  }
+  return match[5];
+};
+
+export const processVideoIds = ({
+  videoId,
+  videoUrl,
+  fallbackVideos,
+}: { videoId: string, videoUrl: string, fallbackVideos: string[] }) => {
+  let youtubeId: string | null = '';
+  const html5Sources: string[] = [];
+
+  if (videoUrl) {
+    if (parseYoutubeId(videoUrl)) {
+      youtubeId = parseYoutubeId(videoUrl);
+    } else {
+      html5Sources.push(videoUrl);
+    }
+  }
+
+  if (fallbackVideos) {
+    fallbackVideos.forEach((src) => (src ? html5Sources.push(src) : null));
+  }
+
+  return {
+    edxVideoId: videoId,
+    html5Sources,
+    youtubeId,
+  };
+};
+
+export const isEdxVideo = (src: string): boolean => {
+  const uuid4Regex = /^[0-9a-fA-F]{8}\b-[0-9a-fA-F]{4}\b-[0-9a-fA-F]{4}\b-[0-9a-fA-F]{4}\b-[0-9a-fA-F]{12}$/;
+  if (src && src.match(uuid4Regex)) {
+    return true;
+  }
+  return false;
+};
+
+export const processLicense = (licenseType, licenseDetails) => {
+  if (licenseType === 'creative-commons') {
+    return 'creative-commons: ver=4.0'.concat(
+      (licenseDetails.attribution ? ' BY' : ''),
+      (licenseDetails.noncommercial ? ' NC' : ''),
+      (licenseDetails.noDerivatives ? ' ND' : ''),
+      (licenseDetails.shareAlike ? ' SA' : ''),
+    );
+  }
+  if (licenseType === 'all-rights-reserved') {
+    return 'all-rights-reserved';
+  }
+  return '';
+};
+
 export const apiMethods = {
   fetchBlockById: ({ blockId, studioEndpointUrl }) => get(
     urls.block({ blockId, studioEndpointUrl }),
@@ -30,7 +107,19 @@ export const apiMethods = {
   fetchStudioView: ({ blockId, studioEndpointUrl }) => get(
     urls.blockStudioView({ studioEndpointUrl, blockId }),
   ),
-  fetchImages: ({ learningContextId, studioEndpointUrl, pageNumber }) => {
+  fetchImages: ({
+    learningContextId,
+    studioEndpointUrl,
+    pageNumber,
+  }): Promise<{ data: AssetResponse & Pagination }> => {
+    if (isLibraryKey(learningContextId)) {
+      // V2 content libraries don't support static assets yet:
+      return Promise.resolve({
+        data: {
+          assets: [], start: 0, end: 0, page: 0, pageSize: 50, totalCount: 0,
+        },
+      });
+    }
     const params = {
       asset_type: 'Images',
       page: pageNumber,
@@ -150,6 +239,12 @@ export const apiMethods = {
     content,
     learningContextId,
     title,
+  }: {
+    blockId: string,
+    blockType: string,
+    content: any, // string for 'html' blocks, otherwise Record<string, any>
+    learningContextId: string,
+    title: string,
   }) => {
     let response = {};
     if (blockType === 'html') {
@@ -175,7 +270,7 @@ export const apiMethods = {
         html5Sources,
         edxVideoId,
         youtubeId,
-      } = module.processVideoIds({
+      } = processVideoIds({
         videoId: content.videoId,
         videoUrl: content.videoSource,
         fallbackVideos: content.fallbackVideos,
@@ -199,7 +294,7 @@ export const apiMethods = {
           handout: content.handout,
           start_time: durationStringFromValue(content.duration.startTime),
           end_time: durationStringFromValue(content.duration.stopTime),
-          license: module.processLicense(content.licenseType, content.licenseDetails),
+          license: processLicense(content.licenseType, content.licenseDetails),
         },
       };
     } else {
@@ -216,7 +311,7 @@ export const apiMethods = {
     title,
   }) => post(
     urls.block({ studioEndpointUrl, blockId }),
-    module.apiMethods.normalizeContent({
+    apiMethods.normalizeContent({
       blockType,
       content,
       blockId,
@@ -239,82 +334,4 @@ export const apiMethods = {
   ),
 };
 
-export const loadImage = (imageData) => ({
-  ...imageData,
-  dateAdded: new Date(imageData.dateAdded.replace(' at', '')).getTime(),
-});
-
-export const loadImages = (rawImages) => camelizeKeys(rawImages).reduce(
-  (obj, image) => ({ ...obj, [image.id]: module.loadImage(image) }),
-  {},
-);
-
-export const processVideoIds = ({
-  videoId,
-  videoUrl,
-  fallbackVideos,
-}) => {
-  let youtubeId = '';
-  const html5Sources = [];
-
-  if (videoUrl) {
-    if (module.parseYoutubeId(videoUrl)) {
-      youtubeId = module.parseYoutubeId(videoUrl);
-    } else {
-      html5Sources.push(videoUrl);
-    }
-  }
-
-  if (fallbackVideos) {
-    fallbackVideos.forEach((src) => (src ? html5Sources.push(src) : null));
-  }
-
-  return {
-    edxVideoId: videoId,
-    html5Sources,
-    youtubeId,
-  };
-};
-
-export const isEdxVideo = (src) => {
-  const uuid4Regex = /^[0-9a-fA-F]{8}\b-[0-9a-fA-F]{4}\b-[0-9a-fA-F]{4}\b-[0-9a-fA-F]{4}\b-[0-9a-fA-F]{12}$/;
-  if (src && src.match(uuid4Regex)) {
-    return true;
-  }
-  return false;
-};
-
-export const parseYoutubeId = (src) => {
-  const youtubeRegex = /^((?:https?:)?\/\/)?((?:www|m)\.)?((?:youtube\.com|youtu.be))(\/(?:[\w-]+\?v=|embed\/|v\/)?)([\w-]+)(\S+)?$/;
-  if (!src.match(youtubeRegex)) {
-    return null;
-  }
-  return src.match(youtubeRegex)[5];
-};
-
-export const processLicense = (licenseType, licenseDetails) => {
-  if (licenseType === 'creative-commons') {
-    return 'creative-commons: ver=4.0'.concat(
-      (licenseDetails.attribution ? ' BY' : ''),
-      (licenseDetails.noncommercial ? ' NC' : ''),
-      (licenseDetails.noDerivatives ? ' ND' : ''),
-      (licenseDetails.shareAlike ? ' SA' : ''),
-    );
-  }
-  if (licenseType === 'all-rights-reserved') {
-    return 'all-rights-reserved';
-  }
-  return '';
-};
-
-export const checkMockApi = (key) => {
-  if (process.env.REACT_APP_DEVGALLERY) {
-    return mockApi[key] ? mockApi[key] : mockApi.emptyMock;
-  }
-  return module.apiMethods[key];
-};
-
-export default Object.keys(apiMethods).reduce(
-  (obj, key) => ({ ...obj, [key]: checkMockApi(key) }),
-  {},
-);
+export default apiMethods;
diff --git a/src/editors/data/services/cms/mockApi.js b/src/editors/data/services/cms/mockApi.js
deleted file mode 100644
index ca50e0c0a6..0000000000
--- a/src/editors/data/services/cms/mockApi.js
+++ /dev/null
@@ -1,297 +0,0 @@
-/* istanbul ignore file */
-import * as urls from './urls';
-
-const mockPromise = (returnValue) => new Promise(resolve => { resolve(returnValue); });
-
-// TODO: update to return block data appropriate per block ID, which will equal block type
-// eslint-disable-next-line
-export const fetchBlockById = ({ blockId, studioEndpointUrl }) => {
-  let data = {};
-  if (blockId === 'html-block-id') {
-    data = {
-      data: `<problem>
-      </problem>`,
-      display_name: 'My Text Prompt',
-      metadata: {
-        display_name: 'Welcome!',
-        download_track: true,
-        download_video: true,
-        edx_video_id: 'f36f06b5-92e5-47c7-bb26-bcf986799cb7',
-        html5_sources: [
-          'https://www.youtube.com/watch?v=dQw4w9WgXcQ',
-          'https://www.youtube.com/watch?v=dQw4w9WgXcQ',
-        ],
-        show_captions: true,
-        sub: '',
-        track: '',
-        transcripts: {
-          en: { filename: 'my-transcript-url' },
-        },
-        xml_attributes: {
-          source: '',
-        },
-        youtube_id_1_0: 'dQw4w9WgXcQ',
-      },
-    };
-  } else if (blockId === 'problem-block-id') {
-    data = {
-      data: `<problem>
-    </problem>`,
-      display_name: 'Dropdown',
-      metadata: {
-        markdown: `You can use this template as a guide to the simple editor markdown and OLX markup to use for dropdown problems. Edit this component to replace this template with your own assessment.
-        >>Add the question text, or prompt, here. This text is required.||You can add an optional tip or note related to the prompt like this. <<
-        [[
-        an incorrect answer
-        (the correct answer)
-        an incorrect answer
-        ]]`,
-        attempts_before_showanswer_button: 7,
-        max_attempts: 5,
-        show_reset_button: true,
-        showanswer: 'after_attempts',
-        submission_wait_seconds: 15,
-        weight: 29,
-      },
-    };
-  } else if (blockId === 'game-block-id') {
-    data = {
-      display_name: 'Game Block',
-      // TODO: insert mock data from backend here
-    };
-  }
-  return mockPromise({ data: { ...data } });
-};
-
-// TODO: update to return block data appropriate per block ID, which will equal block type
-// eslint-disable-next-line
-export const fetchByUnitId = ({ blockId, studioEndpointUrl }) => mockPromise({
-  data: { ancestors: [{ id: 'unitUrl' }] },
-});
-// eslint-disable-next-line
-export const fetchImages = ({ learningContextId, studioEndpointUrl }) => mockPromise({
-  data: {
-    assets: [
-      {
-        displayName: 'shahrukh.jpg',
-        contentType: 'image/jpeg',
-        dateAdded: 'Jan 05, 2022 at 17:38 UTC',
-        url: '/asset-v1:edX+test101+2021_T1+type@asset+block@shahrukh.jpg',
-        externalUrl: 'https://courses.edx.org/asset-v1:edX+test101+2021_T1+type@asset+block@shahrukh.jpg',
-        portableUrl: '/static/shahrukh.jpg',
-        thumbnail: '/asset-v1:edX+test101+2021_T1+type@thumbnail+block@shahrukh.jpg',
-        locked: false,
-        id: 'asset-v1:edX+test101+2021_T1+type@asset+block@shahrukh.jpg',
-      },
-      {
-        displayName: 'IMG_5899.jpg',
-        contentType: 'image/jpeg',
-        dateAdded: 'Nov 16, 2021 at 18:55 UTC',
-        url: '/asset-v1:edX+test101+2021_T1+type@asset+block@IMG_5899.jpg',
-        externalUrl: 'https://courses.edx.org/asset-v1:edX+test101+2021_T1+type@asset+block@IMG_5899.jpg',
-        portableUrl: '/static/IMG_5899.jpg',
-        thumbnail: '/asset-v1:edX+test101+2021_T1+type@thumbnail+block@IMG_5899.jpg',
-        locked: false,
-        id: 'asset-v1:edX+test101+2021_T1+type@asset+block@IMG_5899.jpg',
-      },
-      {
-        displayName: 'ccexample.srt',
-        contentType: 'application/octet-stream',
-        dateAdded: 'Nov 01, 2021 at 15:42 UTC',
-        url: '/asset-v1:edX+test101+2021_T1+type@asset+block@ccexample.srt',
-        externalUrl: 'https://courses.edx.org/asset-v1:edX+test101+2021_T1+type@asset+block@ccexample.srt',
-        portableUrl: '/static/ccexample.srt',
-        thumbnail: null,
-        locked: false,
-        id: 'asset-v1:edX+test101+2021_T1+type@asset+block@ccexample.srt',
-      },
-      {
-        displayName: 'Tennis Ball.jpeg',
-        contentType: 'image/jpeg',
-        dateAdded: 'Aug 04, 2021 at 16:52 UTC',
-        url: '/asset-v1:edX+test101+2021_T1+type@asset+block@Tennis_Ball.jpeg',
-        externalUrl: 'https://courses.edx.org/asset-v1:edX+test101+2021_T1+type@asset+block@Tennis_Ball.jpeg',
-        portableUrl: '/static/Tennis_Ball.jpeg',
-        thumbnail: '/asset-v1:edX+test101+2021_T1+type@thumbnail+block@Tennis_Ball-jpeg.jpg',
-        locked: false,
-        id: 'asset-v1:edX+test101+2021_T1+type@asset+block@Tennis_Ball.jpeg',
-      },
-    ],
-  },
-});
-// eslint-disable-next-line
-export const fetchCourseDetails = ({ studioEndpointUrl, learningContextId }) => mockPromise({
-  data: {
-    // license: "creative-commons: ver=4.0 BY NC",
-    license: 'all-rights-reserved',
-  },
-});
-// eslint-disable-next-line
-export const checkTranscripts = ({youTubeId, studioEndpointUrl, blockId, videoId}) => mockPromise({
-  data: {
-    command: 'import',
-  },
-});
-// eslint-disable-next-line
-export const importTranscript = ({youTubeId, studioEndpointUrl, blockId}) => mockPromise({
-  data: {
-    edx_video_id: 'f36f06b5-92e5-47c7-bb26-bcf986799cb7',
-  },
-});
-// eslint-disable-next-line
-export const fetchAdvanceSettings = ({ studioEndpointUrl, learningContextId }) => mockPromise({
-  data: { allow_unsupported_xblocks: { value: true } },
-});
-// eslint-disable-next-line
-export const fetchVideoFeatures = ({ studioEndpointUrl }) => mockPromise({
-  data: {
-    allowThumbnailUpload: true,
-    videoSharingEnabledForCourse: true,
-  },
-});
-
-export const normalizeContent = ({
-  blockId,
-  blockType,
-  content,
-  learningContextId,
-  title,
-}) => {
-  let response = {};
-  if (blockType === 'html') {
-    response = {
-      category: blockType,
-      couseKey: learningContextId,
-      data: content,
-      has_changes: true,
-      id: blockId,
-      metadata: { display_name: title },
-    };
-  } else if (blockType === 'problem') {
-    response = {
-      data: content.olx,
-      category: blockType,
-      couseKey: learningContextId,
-      has_changes: true,
-      id: blockId,
-      metadata: { display_name: title, ...content.settings },
-    };
-  } else {
-    throw new TypeError(`No Block in V2 Editors named /"${blockType}/", Cannot Save Content.`);
-  }
-  return { ...response };
-};
-
-export const saveBlock = ({
-  blockId,
-  blockType,
-  content,
-  learningContextId,
-  studioEndpointUrl,
-  title,
-}) => mockPromise({
-  url: urls.block({ studioEndpointUrl, blockId }),
-  content: normalizeContent({
-    blockType,
-    content,
-    blockId,
-    learningContextId,
-    title,
-  }),
-});
-
-export const uploadAsset = ({
-  learningContextId,
-  studioEndpointUrl,
-  // image,
-}) => mockPromise({
-  url: urls.courseAssets({ studioEndpointUrl, learningContextId }),
-  asset: {
-    asset: {
-      display_name: 'journey_escape.jpg',
-      content_type: 'image/jpeg',
-      date_added: 'Jan 05, 2022 at 21:26 UTC',
-      url: '/asset-v1:edX+test101+2021_T1+type@asset+block@journey_escape.jpg',
-      external_url: 'https://courses.edx.org/asset-v1:edX+test101+2021_T1+type@asset+block@journey_escape.jpg',
-      portable_url: '/static/journey_escape.jpg',
-      thumbnail: '/asset-v1:edX+test101+2021_T1+type@thumbnail+block@journey_escape.jpg',
-      locked: false,
-      id: 'asset-v1:edX+test101+2021_T1+type@asset+block@journey_escape.jpg',
-    },
-    msg: 'Upload completed',
-  },
-});
-
-// TODO: update to return block data appropriate per block ID, which will equal block type
-// eslint-disable-next-line
-export const fetchStudioView = ({ blockId, studioEndpointUrl }) => {
-  let data = {};
-  if (blockId === 'html-block-id') {
-    data = {
-      data: '<p>Test prompt content</p>',
-      display_name: 'My Text Prompt',
-      metadata: {
-        display_name: 'Welcome!',
-        download_track: true,
-        download_video: true,
-        edx_video_id: 'f36f06b5-92e5-47c7-bb26-bcf986799cb7',
-        html5_sources: [
-          'https://www.youtube.com/watch?v=dQw4w9WgXcQ',
-          'https://www.youtube.com/watch?v=dQw4w9WgXcQ',
-        ],
-        show_captions: true,
-        sub: '',
-        track: '',
-        transcripts: {
-          en: { filename: 'my-transcript-url' },
-        },
-        xml_attributes: {
-          source: '',
-        },
-        youtube_id_1_0: 'dQw4w9WgXcQ',
-      },
-    };
-  } else if (blockId === 'problem-block-id') {
-    data = {
-      data: `<problem>
-      <optionresponse>
-          <p>You can use this template as a guide to the simple editor markdown and OLX markup to use for dropdown problems. Edit this component to replace this template with your own assessment.</p>
-          <label>Add the question text, or prompt, here. This text is required.</label>
-          <description>You can add an optional tip or note related to the prompt like this. </description>
-          <optioninput>
-              <option correct="False">an incorrect answer</option>
-              <option correct="True">the correct answer</option>
-              <option correct="False">an incorrect answer</option>
-          </optioninput>
-      </optionresponse>
-  </problem>`,
-      display_name: 'Dropdown',
-      metadata: {
-        markdown: `You can use this template as a guide to the simple editor markdown and OLX markup to use for dropdown problems. Edit this component to replace this template with your own assessment.
-        >>Add the question text, or prompt, here. This text is required.||You can add an optional tip or note related to the prompt like this. <<
-        [[
-        an incorrect answer
-        (the correct answer)
-        an incorrect answer
-        ]]`,
-        attempts_before_showanswer_button: 7,
-        max_attempts: 5,
-        rerandomize: 'per_student',
-        show_reset_button: true,
-        showanswer: 'after_attempts',
-        submission_wait_seconds: 15,
-        weight: 29,
-      },
-    };
-  }
-
-  return mockPromise({
-    data: {
-      // The following is sent for 'raw' editors.
-      html: blockId.includes('mockRaw') ? 'data-editor="raw"' : '',
-      ...data,
-    },
-  });
-};
-
-export const emptyMock = () => mockPromise({});
diff --git a/src/editors/data/services/cms/types.js b/src/editors/data/services/cms/types.ts
similarity index 94%
rename from src/editors/data/services/cms/types.js
rename to src/editors/data/services/cms/types.ts
index f35ec2441d..f093b12359 100644
--- a/src/editors/data/services/cms/types.js
+++ b/src/editors/data/services/cms/types.ts
@@ -1,6 +1,6 @@
 import PropTypes from 'prop-types';
-import { ProblemTypes, ShowAnswerTypes } from '../../constants/problem';
 
+/*
 export const videoDataProps = {
   videoSource: PropTypes.string,
   videoId: PropTypes.string,
@@ -25,6 +25,7 @@ export const videoDataProps = {
     shareAlike: PropTypes.bool,
   }),
 };
+*/
 
 export const answerOptionProps = PropTypes.shape({
   id: PropTypes.string,
@@ -35,6 +36,7 @@ export const answerOptionProps = PropTypes.shape({
   unselectedFeedback: PropTypes.string,
 });
 
+/*
 export const problemDataProps = {
   rawOLX: PropTypes.string,
   problemType: PropTypes.instanceOf(ProblemTypes),
@@ -68,9 +70,8 @@ export const problemDataProps = {
     }),
   }),
 };
+*/
 
 export default {
-  videoDataProps,
-  problemDataProps,
   answerOptionProps,
 };
diff --git a/src/editors/data/services/cms/urls.test.js b/src/editors/data/services/cms/urls.test.ts
similarity index 95%
rename from src/editors/data/services/cms/urls.test.js
rename to src/editors/data/services/cms/urls.test.ts
index 94b39828c7..95a3968959 100644
--- a/src/editors/data/services/cms/urls.test.js
+++ b/src/editors/data/services/cms/urls.test.ts
@@ -44,7 +44,9 @@ describe('cms url methods', () => {
       },
     };
     it('returns the library page when given the v1 library', () => {
-      expect(returnUrl({ studioEndpointUrl, unitUrl, learningContextId: libraryLearningContextId }))
+      expect(returnUrl({
+        studioEndpointUrl, unitUrl, learningContextId: libraryLearningContextId, blockId: libraryV1Id,
+      }))
         .toEqual(`${studioEndpointUrl}/library/${libraryLearningContextId}`);
     });
     // it('throws error when given the v2 library', () => {
@@ -52,8 +54,9 @@ describe('cms url methods', () => {
     //     .toThrow('Return url not available (or needed) for V2 libraries');
     // });
     it('returns empty url when given the v2 library', () => {
-      expect(returnUrl({ studioEndpointUrl, unitUrl, learningContextId: libraryV2Id }))
-        .toEqual('');
+      expect(returnUrl({
+        studioEndpointUrl, unitUrl, learningContextId: libraryV2Id, blockId: libraryV2Id,
+      })).toEqual('');
     });
     it('returnUrl function should return url with studioEndpointUrl, unitUrl, and blockId', () => {
       expect(returnUrl({
@@ -68,7 +71,9 @@ describe('cms url methods', () => {
         .toEqual('');
     });
     it('throws error if no unit url', () => {
-      expect(returnUrl({ studioEndpointUrl, unitUrl: null, learningContextId: courseId }))
+      expect(returnUrl({
+        studioEndpointUrl, unitUrl: null, learningContextId: courseId, blockId,
+      }))
         .toEqual('');
     });
     it('returns the library page when given the library', () => {
diff --git a/src/editors/data/services/cms/urls.js b/src/editors/data/services/cms/urls.ts
similarity index 54%
rename from src/editors/data/services/cms/urls.js
rename to src/editors/data/services/cms/urls.ts
index d101ff9241..3618499915 100644
--- a/src/editors/data/services/cms/urls.js
+++ b/src/editors/data/services/cms/urls.ts
@@ -1,3 +1,11 @@
+import { isLibraryKey, isLibraryV1Key } from '../../../../generic/key-utils';
+
+/**
+ * A little helper so we can write the types of these functions more compactly
+ * The main purpose of this is to indicate the params are all strings.
+ */
+type UrlFunction = (args: Record<string, string>) => string;
+
 export const libraryV1 = ({ studioEndpointUrl, learningContextId }) => (
   `${studioEndpointUrl}/library/${learningContextId}`
 );
@@ -8,12 +16,14 @@ export const unit = ({ studioEndpointUrl, unitUrl, blockId }) => (
 
 export const returnUrl = ({
   studioEndpointUrl, unitUrl, learningContextId, blockId,
-}) => {
-  if (learningContextId && learningContextId.startsWith('library-v1')) {
+}): string => {
+  // Is this a v1 library?
+  if (isLibraryV1Key(learningContextId)) {
     // when the learning context is a v1 library, return to the library page
     return libraryV1({ studioEndpointUrl, learningContextId });
   }
-  if (learningContextId && learningContextId.startsWith('lib')) {
+  // Is this a v2 library?
+  if (isLibraryKey(learningContextId)) {
     // when it's a v2 library, there will be no return url (instead a closed popup)
     // (temporary) don't throw error, just return empty url. it will fail it's network connection but otherwise
     // the app will run
@@ -28,69 +38,69 @@ export const returnUrl = ({
   return '';
 };
 
-export const block = ({ studioEndpointUrl, blockId }) => (
+export const block = (({ studioEndpointUrl, blockId }) => (
   blockId.startsWith('lb:')
     ? `${studioEndpointUrl}/api/xblock/v2/xblocks/${blockId}/fields/`
     : `${studioEndpointUrl}/xblock/${blockId}`
-);
+)) satisfies UrlFunction;
 
-export const blockAncestor = ({ studioEndpointUrl, blockId }) => {
+export const blockAncestor = (({ studioEndpointUrl, blockId }) => {
   if (blockId.includes('block-v1')) {
     return `${block({ studioEndpointUrl, blockId })}?fields=ancestorInfo`;
   }
   throw new Error('Block ancestor not available (and not needed) for V2 blocks');
-};
+}) satisfies UrlFunction;
 
-export const blockStudioView = ({ studioEndpointUrl, blockId }) => (
+export const blockStudioView = (({ studioEndpointUrl, blockId }) => (
   blockId.includes('block-v1')
     ? `${block({ studioEndpointUrl, blockId })}/studio_view`
     : `${studioEndpointUrl}/api/xblock/v2/xblocks/${blockId}/view/studio_view/`
-);
+)) satisfies UrlFunction;
 
-export const courseAssets = ({ studioEndpointUrl, learningContextId }) => (
+export const courseAssets = (({ studioEndpointUrl, learningContextId }) => (
   `${studioEndpointUrl}/assets/${learningContextId}/`
-);
+)) satisfies UrlFunction;
 
-export const thumbnailUpload = ({ studioEndpointUrl, learningContextId, videoId }) => (
+export const thumbnailUpload = (({ studioEndpointUrl, learningContextId, videoId }) => (
   `${studioEndpointUrl}/video_images/${learningContextId}/${videoId}`
-);
+)) satisfies UrlFunction;
 
-export const videoTranscripts = ({ studioEndpointUrl, blockId }) => (
+export const videoTranscripts = (({ studioEndpointUrl, blockId }) => (
   `${block({ studioEndpointUrl, blockId })}/handler/studio_transcript/translation`
-);
+)) satisfies UrlFunction;
 
-export const downloadVideoTranscriptURL = ({ studioEndpointUrl, blockId, language }) => (
+export const downloadVideoTranscriptURL = (({ studioEndpointUrl, blockId, language }) => (
   `${videoTranscripts({ studioEndpointUrl, blockId })}?language_code=${language}`
-);
+)) satisfies UrlFunction;
 
-export const mediaTranscriptURL = ({ studioEndpointUrl, transcriptUrl }) => (
+export const mediaTranscriptURL = (({ studioEndpointUrl, transcriptUrl }) => (
   `${studioEndpointUrl}${transcriptUrl}`
-);
+)) satisfies UrlFunction;
 
-export const downloadVideoHandoutUrl = ({ studioEndpointUrl, handout }) => (
+export const downloadVideoHandoutUrl = (({ studioEndpointUrl, handout }) => (
   `${studioEndpointUrl}${handout}`
-);
+)) satisfies UrlFunction;
 
-export const courseDetailsUrl = ({ studioEndpointUrl, learningContextId }) => (
+export const courseDetailsUrl = (({ studioEndpointUrl, learningContextId }) => (
   `${studioEndpointUrl}/settings/details/${learningContextId}`
-);
+)) satisfies UrlFunction;
 
-export const checkTranscriptsForImport = ({ studioEndpointUrl, parameters }) => (
+export const checkTranscriptsForImport = (({ studioEndpointUrl, parameters }) => (
   `${studioEndpointUrl}/transcripts/check?data=${parameters}`
-);
+)) satisfies UrlFunction;
 
-export const replaceTranscript = ({ studioEndpointUrl, parameters }) => (
+export const replaceTranscript = (({ studioEndpointUrl, parameters }) => (
   `${studioEndpointUrl}/transcripts/replace?data=${parameters}`
-);
+)) satisfies UrlFunction;
 
-export const courseAdvanceSettings = ({ studioEndpointUrl, learningContextId }) => (
+export const courseAdvanceSettings = (({ studioEndpointUrl, learningContextId }) => (
   `${studioEndpointUrl}/api/contentstore/v0/advanced_settings/${learningContextId}`
-);
+)) satisfies UrlFunction;
 
-export const videoFeatures = ({ studioEndpointUrl }) => (
+export const videoFeatures = (({ studioEndpointUrl }) => (
   `${studioEndpointUrl}/video_features/`
-);
+)) satisfies UrlFunction;
 
-export const courseVideos = ({ studioEndpointUrl, learningContextId }) => (
+export const courseVideos = (({ studioEndpointUrl, learningContextId }) => (
   `${studioEndpointUrl}/videos/${learningContextId}`
-);
+)) satisfies UrlFunction;
diff --git a/src/editors/data/services/cms/utils.test.js b/src/editors/data/services/cms/utils.test.ts
similarity index 91%
rename from src/editors/data/services/cms/utils.test.js
rename to src/editors/data/services/cms/utils.test.ts
index 19aef7a360..868c8a63b6 100644
--- a/src/editors/data/services/cms/utils.test.js
+++ b/src/editors/data/services/cms/utils.test.ts
@@ -10,7 +10,7 @@ describe('cms service utils', () => {
     it('forwards arguments to authenticatedHttpClient().get', () => {
       const get = jest.fn((...args) => ({ get: args }));
       getAuthenticatedHttpClient.mockReturnValue({ get });
-      const args = ['some', 'args', 'for', 'the', 'test'];
+      const args = ['url 1', { headers: {} }] as const;
       expect(utils.get(...args)).toEqual(get(...args));
     });
   });
@@ -18,7 +18,7 @@ describe('cms service utils', () => {
     it('forwards arguments to authenticatedHttpClient().post', () => {
       const post = jest.fn((...args) => ({ post: args }));
       getAuthenticatedHttpClient.mockReturnValue({ post });
-      const args = ['some', 'args', 'for', 'the', 'test'];
+      const args = ['url 2', { headers: {} }] as const;
       expect(utils.post(...args)).toEqual(post(...args));
     });
   });
diff --git a/src/editors/data/services/cms/utils.js b/src/editors/data/services/cms/utils.ts
similarity index 63%
rename from src/editors/data/services/cms/utils.js
rename to src/editors/data/services/cms/utils.ts
index ec9c567417..b7d6276fe7 100644
--- a/src/editors/data/services/cms/utils.js
+++ b/src/editors/data/services/cms/utils.ts
@@ -1,24 +1,25 @@
 import { getAuthenticatedHttpClient } from '@edx/frontend-platform/auth';
+import type { Axios } from 'axios';
+
+export const client: () => Axios = getAuthenticatedHttpClient;
 
 /**
  * get(url)
  * simple wrapper providing an authenticated Http client get action
  * @param {string} url - target url
  */
-export const get = (...args) => getAuthenticatedHttpClient().get(...args);
+export const get: Axios['get'] = (...args) => client().get(...args);
 /**
  * post(url, data)
  * simple wrapper providing an authenticated Http client post action
  * @param {string} url - target url
  * @param {object|string} data - post payload
  */
-export const post = (...args) => getAuthenticatedHttpClient().post(...args);
+export const post: Axios['post'] = (...args) => client().post(...args);
 /**
  * delete(url, data)
  * simple wrapper providing an authenticated Http client delete action
  * @param {string} url - target url
  * @param {object|string} data - delete payload
  */
-export const deleteObject = (...args) => getAuthenticatedHttpClient().delete(...args);
-
-export const client = getAuthenticatedHttpClient;
+export const deleteObject: Axios['delete'] = (...args) => client().delete(...args);
diff --git a/src/editors/sharedComponents/ErrorBoundary/ErrorPage.jsx b/src/editors/sharedComponents/ErrorBoundary/ErrorPage.jsx
index e00552b1aa..f4c32c13d1 100644
--- a/src/editors/sharedComponents/ErrorBoundary/ErrorPage.jsx
+++ b/src/editors/sharedComponents/ErrorBoundary/ErrorPage.jsx
@@ -1,4 +1,3 @@
-import React from 'react';
 import { connect } from 'react-redux';
 import PropTypes from 'prop-types';
 import {
@@ -7,6 +6,7 @@ import {
 
 import { injectIntl, intlShape } from '@edx/frontend-platform/i18n';
 import messages from './messages';
+import { isLibraryV1Key } from '../../../generic/key-utils';
 import { navigateTo } from '../../hooks';
 import { selectors } from '../../data/redux';
 
@@ -23,7 +23,7 @@ const ErrorPage = ({
   // injected
   intl,
 }) => {
-  const outlineType = learningContextId?.startsWith('library-v1') ? 'library' : 'course';
+  const outlineType = isLibraryV1Key(learningContextId) ? 'library' : 'course';
   const outlineUrl = `${studioEndpointUrl}/${outlineType}/${learningContextId}`;
   const unitUrl = unitData?.data ? `${studioEndpointUrl}/container/${unitData?.data.ancestors[0].id}` : null;
 
diff --git a/src/editors/utils/index.js b/src/editors/utils/index.ts
similarity index 100%
rename from src/editors/utils/index.js
rename to src/editors/utils/index.ts
diff --git a/src/generic/key-utils.test.ts b/src/generic/key-utils.test.ts
new file mode 100644
index 0000000000..d3763d27cd
--- /dev/null
+++ b/src/generic/key-utils.test.ts
@@ -0,0 +1,78 @@
+import {
+  getBlockType,
+  getLibraryId,
+  isLibraryKey,
+  isLibraryV1Key,
+} from './key-utils';
+
+describe('component utils', () => {
+  describe('getBlockType', () => {
+    for (const [input, expected] of [
+      ['lb:org:lib:html:id', 'html'],
+      ['lb:OpenCraftX:ALPHA:html:571fe018-f3ce-45c9-8f53-5dafcb422fdd', 'html'],
+      ['lb:Axim:beta:problem:571fe018-f3ce-45c9-8f53-5dafcb422fdd', 'problem'],
+    ]) {
+      it(`returns '${expected}' for usage key '${input}'`, () => {
+        expect(getBlockType(input)).toStrictEqual(expected);
+      });
+    }
+
+    for (const input of ['', undefined, null, 'not a key', 'lb:foo']) {
+      it(`throws an exception for usage key '${input}'`, () => {
+        expect(() => getBlockType(input as any)).toThrow(`Invalid usageKey: ${input}`);
+      });
+    }
+  });
+
+  describe('getLibraryId', () => {
+    for (const [input, expected] of [
+      ['lb:org:lib:html:id', 'lib:org:lib'],
+      ['lb:OpenCraftX:ALPHA:html:571fe018-f3ce-45c9-8f53-5dafcb422fdd', 'lib:OpenCraftX:ALPHA'],
+      ['lb:Axim:beta:problem:571fe018-f3ce-45c9-8f53-5dafcb422fdd', 'lib:Axim:beta'],
+    ]) {
+      it(`returns '${expected}' for usage key '${input}'`, () => {
+        expect(getLibraryId(input)).toStrictEqual(expected);
+      });
+    }
+
+    for (const input of ['', undefined, null, 'not a key', 'lb:foo']) {
+      it(`throws an exception for usage key '${input}'`, () => {
+        expect(() => getLibraryId(input as any)).toThrow(`Invalid usageKey: ${input}`);
+      });
+    }
+  });
+
+  describe('isLibraryKey', () => {
+    for (const [input, expected] of [
+      ['lib:org:lib', true],
+      ['lib:OpenCraftX:ALPHA', true],
+      ['lb:org:lib:html:id', false],
+      ['lb:OpenCraftX:ALPHA:html:571fe018-f3ce-45c9-8f53-5dafcb422fdd', false],
+      ['library-v1:AximX+L1', false],
+      ['course-v1:AximX+TS100+23', false],
+      ['', false],
+      [undefined, false],
+    ] as const) {
+      it(`returns '${expected}' for learning context key '${input}'`, () => {
+        expect(isLibraryKey(input)).toStrictEqual(expected);
+      });
+    }
+  });
+
+  describe('isLibraryV1Key', () => {
+    for (const [input, expected] of [
+      ['library-v1:AximX+L1', true],
+      ['lib:org:lib', false],
+      ['lib:OpenCraftX:ALPHA', false],
+      ['lb:org:lib:html:id', false],
+      ['lb:OpenCraftX:ALPHA:html:571fe018-f3ce-45c9-8f53-5dafcb422fdd', false],
+      ['course-v1:AximX+TS100+23', false],
+      ['', false],
+      [undefined, false],
+    ] as const) {
+      it(`returns '${expected}' for learning context key '${input}'`, () => {
+        expect(isLibraryV1Key(input)).toStrictEqual(expected);
+      });
+    }
+  });
+});
diff --git a/src/generic/key-utils.ts b/src/generic/key-utils.ts
new file mode 100644
index 0000000000..103396fda6
--- /dev/null
+++ b/src/generic/key-utils.ts
@@ -0,0 +1,40 @@
+/**
+ * Given a usage key like `lb:org:lib:html:id`, get the type (e.g. `html`)
+ * @param usageKey e.g. `lb:org:lib:html:id`
+ * @returns The block type as a string
+ */
+export function getBlockType(usageKey: string): string {
+  if (usageKey && usageKey.startsWith('lb:')) {
+    const blockType = usageKey.split(':')[3];
+    if (blockType) {
+      return blockType;
+    }
+  }
+  throw new Error(`Invalid usageKey: ${usageKey}`);
+}
+
+/**
+ * Given a usage key like `lb:org:lib:html:id`, get the library key
+ * @param usageKey e.g. `lb:org:lib:html:id`
+ * @returns The library key, e.g. `lib:org:lib`
+ */
+export function getLibraryId(usageKey: string): string {
+  if (usageKey && usageKey.startsWith('lb:')) {
+    const org = usageKey.split(':')[1];
+    const lib = usageKey.split(':')[2];
+    if (org && lib) {
+      return `lib:${org}:${lib}`;
+    }
+  }
+  throw new Error(`Invalid usageKey: ${usageKey}`);
+}
+
+/** Check if this is a V2 library key. */
+export function isLibraryKey(learningContextKey: string | undefined): learningContextKey is string {
+  return typeof learningContextKey === 'string' && learningContextKey.startsWith('lib:');
+}
+
+/** Check if this is a V1 library key. */
+export function isLibraryV1Key(learningContextKey: string | undefined): learningContextKey is string {
+  return typeof learningContextKey === 'string' && learningContextKey.startsWith('library-v1:');
+}
diff --git a/src/library-authoring/LibraryLayout.tsx b/src/library-authoring/LibraryLayout.tsx
index 5d316a4aa6..59ee11797c 100644
--- a/src/library-authoring/LibraryLayout.tsx
+++ b/src/library-authoring/LibraryLayout.tsx
@@ -27,21 +27,34 @@ const LibraryLayout = () => {
   const goBack = React.useCallback(() => {
     // Go back to the library
     navigate(`/library/${libraryId}`);
-    // The following function is called only if changes are saved:
-    return ({ id: usageKey }) => {
+  }, []);
+  const returnFunction = React.useCallback(() => {
+    // When changes are cancelled, either onClose (goBack) or this returnFunction will be called.
+    // When changes are saved, this returnFunction is called.
+    goBack();
+    return (args) => {
+      if (args === undefined) {
+        return; // Do nothing - the user cancelled the changes
+      }
+      const { id: usageKey } = args;
       // invalidate any queries that involve this XBlock:
       invalidateComponentData(queryClient, libraryId, usageKey);
     };
-  }, []);
+  }, [goBack]);
 
   return (
     <LibraryProvider>
       <Routes>
+        {/*
+          TODO: we should be opening this editor as a modal, not making it a separate page/URL.
+          That will be a much nicer UX because users can just close the modal and be on the same page they were already
+          on, instead of always getting sent back to the library home.
+        */}
         <Route
           path="editor/:blockType/:blockId?"
           element={(
             <PageWrap>
-              <EditorContainer learningContextId={libraryId} onClose={goBack} afterSave={goBack} />
+              <EditorContainer learningContextId={libraryId} onClose={goBack} returnFunction={returnFunction} />
             </PageWrap>
           )}
         />
diff --git a/src/library-authoring/__mocks__/libraryComponentsMock.ts b/src/library-authoring/__mocks__/libraryComponentsMock.ts
index 6e1db6a719..48a920392a 100644
--- a/src/library-authoring/__mocks__/libraryComponentsMock.ts
+++ b/src/library-authoring/__mocks__/libraryComponentsMock.ts
@@ -2,8 +2,9 @@ export default [
   {
     id: '1',
     usageKey: 'lb:org:lib:html:1',
-    displayName: 'Text',
+    displayName: 'Text Component 1',
     formatted: {
+      displayName: 'Text Component 1',
       content: {
         htmlContent: 'This is a text: ID=1',
       },
@@ -11,13 +12,14 @@ export default [
     tags: {
       level0: ['1', '2', '3'],
     },
-    blockType: 'text',
+    blockType: 'html',
   },
   {
     id: '2',
     usageKey: 'lb:org:lib:html:2',
-    displayName: 'Text',
+    displayName: 'Text Component 2',
     formatted: {
+      displayName: 'Text Component 2',
       content: {
         htmlContent: 'This is a text: ID=2',
       },
@@ -25,15 +27,15 @@ export default [
     tags: {
       level0: ['1', '2', '3'],
     },
-    blockType: 'text',
+    blockType: 'html',
   },
   {
     id: '3',
     usageKey: 'lb:org:lib:video:3',
-    displayName: 'Video',
+    displayName: 'Video Component 3',
     formatted: {
+      displayName: 'Video Component 3',
       content: {
-        htmlContent: 'This is a video: ID=3',
       },
     },
     tags: {
@@ -44,24 +46,24 @@ export default [
   {
     id: '4',
     usageKey: 'lb:org:lib:video:4',
-    displayName: 'Video',
+    displayName: 'Video Component 4',
     formatted: {
-      content: {
-        htmlContent: 'This is a video: ID=4',
-      },
+      displayName: 'Video Component 4',
+      content: {},
     },
     tags: {
       level0: ['1', '2'],
     },
-    blockType: 'text',
+    blockType: 'video',
   },
   {
     id: '5',
     usageKey: 'lb:org:lib:problem:5',
     displayName: 'Problem',
     formatted: {
+      displayName: 'Problem',
       content: {
-        htmlContent: 'This is a problem: ID=5',
+        capaContent: 'This is a problem: ID=5',
       },
     },
     blockType: 'problem',
@@ -71,8 +73,9 @@ export default [
     usageKey: 'lb:org:lib:problem:6',
     displayName: 'Problem',
     formatted: {
+      displayName: 'Problem',
       content: {
-        htmlContent: 'This is a problem: ID=6',
+        capaContent: 'This is a problem: ID=6',
       },
     },
     blockType: 'problem',
diff --git a/src/library-authoring/add-content/AddContentWorkflow.test.tsx b/src/library-authoring/add-content/AddContentWorkflow.test.tsx
index 5a77c92953..7bc17321ad 100644
--- a/src/library-authoring/add-content/AddContentWorkflow.test.tsx
+++ b/src/library-authoring/add-content/AddContentWorkflow.test.tsx
@@ -85,20 +85,55 @@ describe('AddContentWorkflow test', () => {
   });
 
   it('can create a Problem component', async () => {
-    const { mockShowToast } = initializeMocks();
+    initializeMocks();
     render(<LibraryLayout />, renderOpts);
 
     // Click "New [Component]"
     const newComponentButton = await screen.findByRole('button', { name: /New/ });
     fireEvent.click(newComponentButton);
 
-    // Pre-condition - this is NOT shown yet:
-    expect(screen.queryByText('Content created successfully.')).not.toBeInTheDocument();
-
     // Click "Problem" to create a capa problem component
     fireEvent.click(await screen.findByRole('button', { name: /Problem/ }));
 
-    // We haven't yet implemented the problem editor, so we expect only a toast to appear
+    // Then the editor should open
+    expect(await screen.findByRole('heading', { name: /Select problem type/ })).toBeInTheDocument();
+
+    // Select the type: Numerical Input
+    fireEvent.click(await screen.findByRole('button', { name: 'Numerical input' }));
+    fireEvent.click(screen.getByRole('button', { name: 'Select' }));
+
+    expect(await screen.findByRole('heading', { name: /Numerical input/ })).toBeInTheDocument();
+
+    // Enter an answer value:
+    const inputA = await screen.findByPlaceholderText('Enter an answer');
+    fireEvent.change(inputA, { target: { value: '123456' } });
+
+    // Mock the save() REST API method:
+    const saveSpy = jest.spyOn(editorCmsApi as any, 'saveBlock').mockImplementationOnce(async () => ({
+      status: 200, data: { id: mockXBlockFields.usageKeyNewProblem },
+    }));
+
+    // Click Save
+    const saveButton = screen.getByLabelText('Save changes and return to learning context');
+    fireEvent.click(saveButton);
+    expect(saveSpy).toHaveBeenCalledTimes(2); // TODO: why is this called twice?
+  });
+
+  it('can create a Video component', async () => {
+    const { mockShowToast } = initializeMocks();
+    render(<LibraryLayout />, renderOpts);
+
+    // Click "New [Component]"
+    const newComponentButton = await screen.findByRole('button', { name: /New/ });
+    fireEvent.click(newComponentButton);
+
+    // Pre-condition - the success toast is NOT shown yet:
+    expect(mockShowToast).not.toHaveBeenCalled();
+
+    // Click "Video" to create a video component
+    fireEvent.click(await screen.findByRole('button', { name: /Video/ }));
+
+    // We haven't yet implemented the video editor, so we expect only a toast to appear
     await waitFor(() => expect(mockShowToast).toHaveBeenCalledWith('Content created successfully.'));
   });
 });
diff --git a/src/library-authoring/components/ComponentCard.test.tsx b/src/library-authoring/components/ComponentCard.test.tsx
index cb800e762e..dae278eba7 100644
--- a/src/library-authoring/components/ComponentCard.test.tsx
+++ b/src/library-authoring/components/ComponentCard.test.tsx
@@ -34,7 +34,7 @@ const contentHit: ContentHit = {
   tags: {
     level0: ['1', '2', '3'],
   },
-  blockType: 'text',
+  blockType: 'html',
   created: 1722434322294,
   modified: 1722434322294,
   lastPublished: null,
diff --git a/src/library-authoring/components/ComponentCard.tsx b/src/library-authoring/components/ComponentCard.tsx
index 6978fd6d9d..39a23926fc 100644
--- a/src/library-authoring/components/ComponentCard.tsx
+++ b/src/library-authoring/components/ComponentCard.tsx
@@ -74,7 +74,11 @@ const ComponentCard = ({ contentHit, blockTypeDisplayName } : ComponentCardProps
     tags,
     usageKey,
   } = contentHit;
-  const description = formatted?.content?.htmlContent ?? '';
+  const description: string = (/* eslint-disable */
+    blockType === 'html' ? formatted?.content?.htmlContent :
+    blockType === 'problem' ? formatted?.content?.capaContent :
+    undefined
+  ) ?? '';/* eslint-enable */
   const displayName = formatted?.displayName ?? '';
 
   return (
diff --git a/src/library-authoring/components/LibraryComponents.test.tsx b/src/library-authoring/components/LibraryComponents.test.tsx
index fd45dac12c..ed490b92d6 100644
--- a/src/library-authoring/components/LibraryComponents.test.tsx
+++ b/src/library-authoring/components/LibraryComponents.test.tsx
@@ -173,8 +173,8 @@ describe('<LibraryComponents />', () => {
 
     expect(await screen.findByText('This is a text: ID=1')).toBeInTheDocument();
     expect(screen.getByText('This is a text: ID=2')).toBeInTheDocument();
-    expect(screen.getByText('This is a video: ID=3')).toBeInTheDocument();
-    expect(screen.getByText('This is a video: ID=4')).toBeInTheDocument();
+    expect(screen.getByText('Video Component 3')).toBeInTheDocument();
+    expect(screen.getByText('Video Component 4')).toBeInTheDocument();
     expect(screen.getByText('This is a problem: ID=5')).toBeInTheDocument();
     expect(screen.getByText('This is a problem: ID=6')).toBeInTheDocument();
   });
@@ -189,8 +189,8 @@ describe('<LibraryComponents />', () => {
 
     expect(await screen.findByText('This is a text: ID=1')).toBeInTheDocument();
     expect(screen.getByText('This is a text: ID=2')).toBeInTheDocument();
-    expect(screen.getByText('This is a video: ID=3')).toBeInTheDocument();
-    expect(screen.getByText('This is a video: ID=4')).toBeInTheDocument();
+    expect(screen.getByText('Video Component 3')).toBeInTheDocument();
+    expect(screen.getByText('Video Component 4')).toBeInTheDocument();
     expect(screen.queryByText('This is a problem: ID=5')).not.toBeInTheDocument();
     expect(screen.queryByText('This is a problem: ID=6')).not.toBeInTheDocument();
   });
diff --git a/src/library-authoring/components/utils.test.ts b/src/library-authoring/components/utils.test.ts
index 8d09c43986..b31018d27d 100644
--- a/src/library-authoring/components/utils.test.ts
+++ b/src/library-authoring/components/utils.test.ts
@@ -1,50 +1,14 @@
-import { getBlockType, getEditUrl, getLibraryId } from './utils';
+import { getEditUrl } from './utils';
 
 describe('component utils', () => {
-  describe('getBlockType', () => {
-    for (const [input, expected] of [
-      ['lb:org:lib:html:id', 'html'],
-      ['lb:OpenCraftX:ALPHA:html:571fe018-f3ce-45c9-8f53-5dafcb422fdd', 'html'],
-      ['lb:Axim:beta:problem:571fe018-f3ce-45c9-8f53-5dafcb422fdd', 'problem'],
-    ]) {
-      it(`returns '${expected}' for usage key '${input}'`, () => {
-        expect(getBlockType(input)).toStrictEqual(expected);
-      });
-    }
-
-    for (const input of ['', undefined, null, 'not a key', 'lb:foo']) {
-      it(`throws an exception for usage key '${input}'`, () => {
-        expect(() => getBlockType(input as any)).toThrow(`Invalid usageKey: ${input}`);
-      });
-    }
-  });
-
-  describe('getLibraryId', () => {
-    for (const [input, expected] of [
-      ['lb:org:lib:html:id', 'lib:org:lib'],
-      ['lb:OpenCraftX:ALPHA:html:571fe018-f3ce-45c9-8f53-5dafcb422fdd', 'lib:OpenCraftX:ALPHA'],
-      ['lb:Axim:beta:problem:571fe018-f3ce-45c9-8f53-5dafcb422fdd', 'lib:Axim:beta'],
-    ]) {
-      it(`returns '${expected}' for usage key '${input}'`, () => {
-        expect(getLibraryId(input)).toStrictEqual(expected);
-      });
-    }
-
-    for (const input of ['', undefined, null, 'not a key', 'lb:foo']) {
-      it(`throws an exception for usage key '${input}'`, () => {
-        expect(() => getLibraryId(input as any)).toThrow(`Invalid usageKey: ${input}`);
-      });
-    }
-  });
-
   describe('getEditUrl', () => {
     it('returns the right URL for an HTML (Text) block', () => {
       const usageKey = 'lb:org:ALPHA:html:571fe018-f3ce-45c9-8f53-5dafcb422fdd';
       expect(getEditUrl(usageKey)).toStrictEqual(`/library/lib:org:ALPHA/editor/html/${usageKey}`);
     });
-    it('doesn\'t yet allow editing a problem block', () => {
+    it('returns the right URL for editing a Problem block', () => {
       const usageKey = 'lb:org:beta:problem:571fe018-f3ce-45c9-8f53-5dafcb422fdd';
-      expect(getEditUrl(usageKey)).toBeUndefined();
+      expect(getEditUrl(usageKey)).toStrictEqual(`/library/lib:org:beta/editor/problem/${usageKey}`);
     });
     it('doesn\'t yet allow editing a video block', () => {
       const usageKey = 'lb:org:beta:video:571fe018-f3ce-45c9-8f53-5dafcb422fdd';
diff --git a/src/library-authoring/components/utils.ts b/src/library-authoring/components/utils.ts
index 095d956a00..2b99dcc2b1 100644
--- a/src/library-authoring/components/utils.ts
+++ b/src/library-authoring/components/utils.ts
@@ -1,34 +1,6 @@
-/**
- * Given a usage key like `lb:org:lib:html:id`, get the type (e.g. `html`)
- * @param usageKey e.g. `lb:org:lib:html:id`
- * @returns The block type as a string
- */
-export function getBlockType(usageKey: string): string {
-  if (usageKey && usageKey.startsWith('lb:')) {
-    const blockType = usageKey.split(':')[3];
-    if (blockType) {
-      return blockType;
-    }
-  }
-  throw new Error(`Invalid usageKey: ${usageKey}`);
-}
-
-/**
- * Given a usage key like `lb:org:lib:html:id`, get the library key
- * @param usageKey e.g. `lb:org:lib:html:id`
- * @returns The library key, e.g. `lib:org:lib`
- */
-export function getLibraryId(usageKey: string): string {
-  if (usageKey && usageKey.startsWith('lb:')) {
-    const org = usageKey.split(':')[1];
-    const lib = usageKey.split(':')[2];
-    if (org && lib) {
-      return `lib:${org}:${lib}`;
-    }
-  }
-  throw new Error(`Invalid usageKey: ${usageKey}`);
-}
+import { getBlockType, getLibraryId } from '../../generic/key-utils';
 
+/* eslint-disable import/prefer-default-export */
 export function getEditUrl(usageKey: string): string | undefined {
   let blockType: string;
   let libraryId: string;
@@ -39,7 +11,8 @@ export function getEditUrl(usageKey: string): string | undefined {
     return undefined;
   }
 
-  const mfeEditorTypes = ['html'];
+  // Which XBlock/component types are supported by the 'editors' built in to this repo?
+  const mfeEditorTypes = ['html', 'problem'];
   if (mfeEditorTypes.includes(blockType)) {
     return `/library/${libraryId}/editor/${blockType}/${usageKey}`;
   }
diff --git a/src/library-authoring/data/api.mocks.ts b/src/library-authoring/data/api.mocks.ts
index 480e78d661..0002f7516a 100644
--- a/src/library-authoring/data/api.mocks.ts
+++ b/src/library-authoring/data/api.mocks.ts
@@ -112,11 +112,14 @@ mockContentLibrary.applyMock = () => jest.spyOn(api, 'getContentLibrary').mockIm
 export async function mockCreateLibraryBlock(
   args: api.CreateBlockDataRequest,
 ): ReturnType<typeof api.createLibraryBlock> {
-  if (args.blockType === 'html' && args.libraryId === mockContentLibrary.libraryId) {
-    return mockCreateLibraryBlock.newHtmlData;
-  }
-  if (args.blockType === 'problem' && args.libraryId === mockContentLibrary.libraryId) {
-    return mockCreateLibraryBlock.newProblemData;
+  if (args.libraryId === mockContentLibrary.libraryId) {
+    switch (args.blockType) {
+      case 'html': return mockCreateLibraryBlock.newHtmlData;
+      case 'problem': return mockCreateLibraryBlock.newProblemData;
+      case 'video': return mockCreateLibraryBlock.newVideoData;
+      default:
+        // Continue to error handling below.
+    }
   }
   throw new Error(`mockCreateLibraryBlock doesn't know how to mock ${JSON.stringify(args)}`);
 }
@@ -146,6 +149,19 @@ mockCreateLibraryBlock.newProblemData = {
   created: '2024-07-22T21:37:49Z',
   tagsCount: 0,
 } satisfies api.LibraryBlockMetadata;
+mockCreateLibraryBlock.newVideoData = {
+  id: 'lb:Axim:TEST:video:prob1',
+  defKey: 'video1',
+  blockType: 'video',
+  displayName: 'New Video',
+  hasUnpublishedChanges: true,
+  lastPublished: null, // or e.g. '2024-08-30T16:37:42Z',
+  publishedBy: null, // or e.g. 'test_author',
+  lastDraftCreated: '2024-07-22T21:37:49Z',
+  lastDraftCreatedBy: null,
+  created: '2024-07-22T21:37:49Z',
+  tagsCount: 0,
+} satisfies api.LibraryBlockMetadata;
 /** Apply this mock. Returns a spy object that can tell you if it's been called. */
 mockCreateLibraryBlock.applyMock = () => (
   jest.spyOn(api, 'createLibraryBlock').mockImplementation(mockCreateLibraryBlock)
@@ -163,6 +179,7 @@ export async function mockXBlockFields(usageKey: string): Promise<api.XBlockFiel
   switch (usageKey) {
     case thisMock.usageKeyHtml: return thisMock.dataHtml;
     case thisMock.usageKeyNewHtml: return thisMock.dataNewHtml;
+    case thisMock.usageKeyNewProblem: return thisMock.dataNewProblem;
     default: throw new Error(`No mock has been set up for usageKey "${usageKey}"`);
   }
 }
@@ -180,6 +197,13 @@ mockXBlockFields.dataNewHtml = {
   data: '',
   metadata: { displayName: 'New Text Component' },
 } satisfies api.XBlockFields;
+// Mock of a blank/new problem (CAPA) block:
+mockXBlockFields.usageKeyNewProblem = 'lb:Axim:TEST:problem:prob1';
+mockXBlockFields.dataNewProblem = {
+  displayName: 'New Problem Component',
+  data: '',
+  metadata: { displayName: 'New Problem Component' },
+} satisfies api.XBlockFields;
 /** Apply this mock. Returns a spy object that can tell you if it's been called. */
 mockXBlockFields.applyMock = () => jest.spyOn(api, 'getXBlockFields').mockImplementation(mockXBlockFields);
 
diff --git a/src/library-authoring/data/apiHooks.ts b/src/library-authoring/data/apiHooks.ts
index 91b07c6a7f..efbd59efc0 100644
--- a/src/library-authoring/data/apiHooks.ts
+++ b/src/library-authoring/data/apiHooks.ts
@@ -7,7 +7,7 @@ import {
   type QueryClient,
 } from '@tanstack/react-query';
 
-import { getLibraryId } from '../components/utils';
+import { getLibraryId } from '../../generic/key-utils';
 import {
   type GetLibrariesV2CustomParams,
   type ContentLibrary,
diff --git a/src/search-modal/SearchResult.tsx b/src/search-modal/SearchResult.tsx
index 6d7e618f94..9ba6ee9516 100644
--- a/src/search-modal/SearchResult.tsx
+++ b/src/search-modal/SearchResult.tsx
@@ -11,6 +11,7 @@ import { useSelector } from 'react-redux';
 import { useNavigate } from 'react-router-dom';
 
 import { getItemIcon } from '../generic/block-type-utils';
+import { isLibraryKey } from '../generic/key-utils';
 import { useSearchContext, type ContentHit, Highlight } from '../search-manager';
 import { getStudioHomeData } from '../studio-home/data/selectors';
 import { constructLibraryAuthoringURL } from '../utils';
@@ -116,7 +117,7 @@ const SearchResult: React.FC<{ hit: ContentHit }> = ({ hit }) => {
       return `/${urlSuffix}`;
     }
 
-    if (contextKey.startsWith('lib:')) {
+    if (isLibraryKey(contextKey)) {
       const urlSuffix = getLibraryComponentUrlSuffix(hit);
       if (redirectToLibraryAuthoringMfe && libraryAuthoringMfeUrl) {
         return constructLibraryAuthoringURL(libraryAuthoringMfeUrl, urlSuffix);