diff --git a/src/browser/init.ts b/src/browser/init.ts
index 42c792c1..f3cb9fda 100644
--- a/src/browser/init.ts
+++ b/src/browser/init.ts
@@ -1,13 +1,7 @@
 import '@stencila/components'
-import {
-  codeChunk,
-  Node,
-  softwareEnvironment,
-  softwareSession,
-  SoftwareSession
-} from '@stencila/schema'
-import { ClientType } from '../base/Client'
+import { CodeChunk, softwareSession, SoftwareSession } from '@stencila/schema'
 import { BaseExecutor } from '../base/BaseExecutor'
+import { ClientType } from '../base/Client'
 import { HttpAddress } from '../base/Transports'
 import { discover } from '../http/discover'
 import { HttpClient } from '../http/HttpClient'
@@ -16,20 +10,21 @@ import { WebSocketClient } from '../ws/WebSocketClient'
 let executor: BaseExecutor
 let session: null | SoftwareSession = null
 
-const executeCodeChunk = async (text: string): Promise<Node> => {
-  const code = codeChunk(text, { programmingLanguage: 'python' })
-
+const executeCodeChunk = async (codeChunk: CodeChunk): Promise<CodeChunk> => {
   if (session === null) {
     session = await executor.begin(softwareSession())
   }
 
-  return executor.execute(code, session)
+  return executor.execute(codeChunk)
 }
 
-const executeHandler = (text: string): Promise<void> =>
-  executeCodeChunk(text)
-    .then(res => console.log(res))
-    .catch(err => console.error(err))
+const executeHandler = (codeChunk: CodeChunk): Promise<CodeChunk> =>
+  executeCodeChunk(codeChunk)
+    .then(res => res)
+    .catch(err => {
+      console.error(err)
+      return codeChunk
+    })
 
 const setCodeChunkProps = (): void => {
   const codeChunks = document.querySelectorAll('stencila-code-chunk')