diff --git a/Resources/opencode-plugin.js b/Resources/opencode-plugin.js
index 9bfe512096b8..2235a664c736 100644
--- a/Resources/opencode-plugin.js
+++ b/Resources/opencode-plugin.js
@@ -427,6 +427,10 @@ export const CMUXFeed = async (ctx) => {
       typeof process.env.CMUX_WORKSPACE_ID === "string" && process.env.CMUX_WORKSPACE_ID.trim()
         ? process.env.CMUX_WORKSPACE_ID.trim()
         : null;
+    const surfaceId =
+      typeof process.env.CMUX_SURFACE_ID === "string" && process.env.CMUX_SURFACE_ID.trim()
+        ? process.env.CMUX_SURFACE_ID.trim()
+        : null;
     const event = {
       session_id: `opencode-${sessionId}`,
       _source: "opencode",
@@ -435,6 +439,7 @@ export const CMUXFeed = async (ctx) => {
       ...extra,
     };
     if (workspaceId) event.workspace_id = workspaceId;
+    if (surfaceId) event.surface_id = surfaceId;
     if (context) event.context = context;
     return event;
   };