diff --git a/slug/apps/kang/backend.js b/slug/apps/kang/backend.js
index a62c3888..478c5831 100755
--- a/slug/apps/kang/backend.js
+++ b/slug/apps/kang/backend.js
@@ -95,6 +95,7 @@ if (parsedArgs.values['test-highlight']) {
     absolutePath,
     relativePath,
     newFile, 
+    hasLanguageModel: !!doHighlight,
   });
   // TODO thread stdin in case it had some data in it before we went to web mode
   // send a secret message and wait for it to come back.
@@ -116,16 +117,16 @@ function setupHighlight() {
     terminal: false,
   });
   rl.on('line', line => {
-    const {id, tokens, error} = JSON.parse(line);
+    const {id, result, error} = JSON.parse(line);
     if (error)
       higlightCallbacks.get(id).reject(new Error(error));
     else
-      higlightCallbacks.get(id).resolve(tokens);
+      higlightCallbacks.get(id).resolve(result);
   });
   process.on('beforeExit', () => {
     commandChild.kill();
   });
   return (content, id) => {
-    commandChild.stdin.write(JSON.stringify({content, id}) + '\n');
+    commandChild.stdin.write(JSON.stringify({method: 'highlight', params: {content}, id}) + '\n');
   };
 }
\ No newline at end of file
diff --git a/slug/apps/kang/web.ts b/slug/apps/kang/web.ts
index 56ebe2c3..19058a66 100644
--- a/slug/apps/kang/web.ts
+++ b/slug/apps/kang/web.ts
@@ -133,7 +133,7 @@ const rpc = RPC(transport, {
       }  
     });
     window['editorForTest'] = editor;
-    updateEditorMode(true);
+    updateEditorMode(!params.hasLanguageModel);
     editorContainer.append(editor.element);
     editor.layout();
     lastSavedVersion = editor.value;
diff --git a/slug/editor/js/highlighter.ts b/slug/editor/js/highlighter.ts
index d659e91f..399d6282 100644
--- a/slug/editor/js/highlighter.ts
+++ b/slug/editor/js/highlighter.ts
@@ -21,7 +21,7 @@ export class Highlighter extends Emitter<{
   'highlight': {from: number, to: number};
 }> {
   private _selectionColors: {color?: string, background?: string};
-  private _mode: Mode<any>;
+  private _mode: Mode<any> | null;
   private _lineInfo = new WeakMap<import('./model').Line, {state: any, tokens: Array<Token>}>();
   private _currentLineNumber = 0;
   private _requestLineNumber = 0;
@@ -176,6 +176,8 @@ export class Highlighter extends Emitter<{
   }
 
   indentation(lineNumber: number): number {
+    if (!this._mode)
+      return 0;
     const line = this._model.line(lineNumber);
     if (!this._lineInfo.has(line))
       return 0;
@@ -265,7 +267,7 @@ export class Highlighter extends Emitter<{
   }
 
   hoverForLocation(loc: Loc): { content: string | Node, reposition: Loc } | null {
-    if (!this._mode.hover)
+    if (!this._mode?.hover)
       return null;
     const line = this._model.line(loc.line);
     if (!line)
diff --git a/slug/sdk/index.js b/slug/sdk/index.js
index 1f9b2951..5ec3744e 100644
--- a/slug/sdk/index.js
+++ b/slug/sdk/index.js
@@ -44,8 +44,14 @@ class Transport {
         this._sawSecret = true;
       }
       setImmediate(() => {
-        if (this.onmessage)
-          this.onmessage.call(null, JSON.parse(message));
+        let parsed;
+        try {
+          parsed = JSON.parse(message);
+        } catch {
+          console.error(JSON.stringify(message));
+          throw new Error('failed to parse json');
+        }
+        this.onmessage.call(null, parsed);
       });
     };
     sendMessage(this._pendingMessage + buffer.toString(undefined, 0, end));