diff --git a/.github/CODEOWNERS b/.github/CODEOWNERS
index f5f20b233d..32267be127 100644
--- a/.github/CODEOWNERS
+++ b/.github/CODEOWNERS
@@ -725,6 +725,7 @@
 /types/cucumber/                                    @abraaoalves @jan-molak @isoung @BendingBender @ErikSchierboom
 /types/currency-formatter/                          @mhegazy @davidmpaz
 /types/custom-error-generator/                      @thmiceli
+/types/custom-functions-runtime/                    @OfficeDev @Zlatkovsky @mscharlock @kbrandl
 /types/cwise/                                       @taoqf
 /types/cwise-compiler/                              @taoqf
 /types/cwise-parser/                                @taoqf
@@ -3132,7 +3133,8 @@
 /types/oclazyload/                                  @rolandzwaga
 /types/odata/                                       @janhommes @jcchalte
 /types/ofe/                                         @Morfent
-/types/office-js/                                   @OfficeDev @LanceEA @Zlatkovsky @kbrandl @Rick-Kirkham @AlexJerabek @ElizabethSamuel-MSFT
+/types/office-js/                                   @OfficeDev @LanceEA @Zlatkovsky @kbrandl @Rick-Kirkham @AlexJerabek @ElizabethSamuel-MSFT @mscharlock
+/types/office-runtime/                              @OfficeDev @mscharlock @kbrandl @Zlatkovsky
 /types/offline-js/                                  @cgwrench
 /types/oibackoff/                                   @geoffreak
 /types/oidc-token-manager/                          @rosieks
diff --git a/types/custom-functions-runtime/custom-functions-runtime-tests.ts b/types/custom-functions-runtime/custom-functions-runtime-tests.ts
index 86eecbedda..fc24ae6491 100644
--- a/types/custom-functions-runtime/custom-functions-runtime-tests.ts
+++ b/types/custom-functions-runtime/custom-functions-runtime-tests.ts
@@ -3,7 +3,7 @@ function addTen(n: number) {
     return n + 10;
 }
 
-/*Assume that the function id for addTen in the function's JSON metadata is specified as ADDTEN. */
+/* Assume that the function id for addTen in the function's JSON metadata is specified as ADDTEN. */
 CustomFunctionMappings.ADDTEN = addTen;
 
 async function getStockValues(ticker: string): Promise<number> {
diff --git a/types/custom-functions-runtime/index.d.ts b/types/custom-functions-runtime/index.d.ts
index f2c20f24eb..adf5433f41 100644
--- a/types/custom-functions-runtime/index.d.ts
+++ b/types/custom-functions-runtime/index.d.ts
@@ -10,15 +10,24 @@ Copyright (c) Microsoft Corporation
 */
 
 /**
- * Specific to Excel Custom Functions. Enables you to set key-value pairs (a function's JSON id : JavaScript name).
+ * Specific to Excel Custom Functions.
+ * Enables you to set key-value pairs which map
+ * a function's id in the JSON metadata to the JS function name.
+ * @beta
  */
 declare let CustomFunctionMappings: { [key: string]: Function };
 /**
  * CustomFunctions namespace, used by Excel Custom Functions
+ * @beta
  */
 declare namespace CustomFunctions {
     /**
-     * StreamingHandler interface
+     * A handler passed automatically as the last parameter
+     * to a streaming function. With this parameter, a
+     * function can use handler.setResult to set a cell value
+     * or hook into the handler.onCanceled event to
+     * to handle what happens when the function stops streaming.
+     * @beta
      */
     interface StreamingHandler<T> extends CancelableHandler {
         /**