feat(app): use opentui markdown component behind experimental flag (#10900)

packages/opencode/src/cli/cmd/tui/routes/session/index.tsx

@@ -58,6 +58,7 @@ import { DialogTimeline } from "./dialog-timeline"
 import { DialogForkFromTimeline } from "./dialog-fork-from-timeline"
 import { DialogSessionRename } from "../../component/dialog-session-rename"
 import { Sidebar } from "./sidebar"
+import { Flag } from "@/flag/flag"
 import { LANGUAGE_EXTENSIONS } from "@/lsp/language"
 import parsers from "../../../../../../parsers-config.ts"
 import { Clipboard } from "../../util/clipboard"
@@ -1338,15 +1339,26 @@ function TextPart(props: { last: boolean; part: TextPart; message: AssistantMess
   return (
     <Show when={props.part.text.trim()}>
       <box id={"text-" + props.part.id} paddingLeft={3} marginTop={1} flexShrink={0}>
-        <code
-          filetype="markdown"
-          drawUnstyledText={false}
-          streaming={true}
-          syntaxStyle={syntax()}
-          content={props.part.text.trim()}
-          conceal={ctx.conceal()}
-          fg={theme.text}
-        />
+        <Switch>
+          <Match when={Flag.OPENCODE_EXPERIMENTAL_MARKDOWN}>
+            <markdown
+              syntaxStyle={syntax()}
+              content={props.part.text.trim()}
+              conceal={ctx.conceal()}
+            />
+          </Match>
+          <Match when={!Flag.OPENCODE_EXPERIMENTAL_MARKDOWN}>
+            <code
+              filetype="markdown"
+              drawUnstyledText={false}
+              streaming={true}
+              syntaxStyle={syntax()}
+              content={props.part.text.trim()}
+              conceal={ctx.conceal()}
+              fg={theme.text}
+            />
+          </Match>
+        </Switch>
       </box>
     </Show>
   )

packages/opencode/src/flag/flag.ts

@@ -46,6 +46,7 @@ export namespace Flag {
   export const OPENCODE_EXPERIMENTAL_LSP_TOOL = OPENCODE_EXPERIMENTAL || truthy("OPENCODE_EXPERIMENTAL_LSP_TOOL")
   export const OPENCODE_DISABLE_FILETIME_CHECK = truthy("OPENCODE_DISABLE_FILETIME_CHECK")
   export const OPENCODE_EXPERIMENTAL_PLAN_MODE = OPENCODE_EXPERIMENTAL || truthy("OPENCODE_EXPERIMENTAL_PLAN_MODE")
+  export const OPENCODE_EXPERIMENTAL_MARKDOWN = OPENCODE_EXPERIMENTAL || truthy("OPENCODE_EXPERIMENTAL_MARKDOWN")
   export const OPENCODE_MODELS_URL = process.env["OPENCODE_MODELS_URL"]
 
   function number(key: string) {