diff --git a/packages/opencode/src/cli/cmd/tui/app.tsx b/packages/opencode/src/cli/cmd/tui/app.tsx
index 5cb249da7c..8256217d05 100644
--- a/packages/opencode/src/cli/cmd/tui/app.tsx
+++ b/packages/opencode/src/cli/cmd/tui/app.tsx
@@ -247,21 +247,12 @@ function App() {
           })
         local.model.set({ providerID, modelID }, { recent: true })
       }
-      if (args.sessionID) {
-        if (args.fork) {
-          sdk.client.session.fork({ sessionID: args.sessionID }).then((result) => {
-            if (result.data?.id) {
-              route.navigate({ type: "session", sessionID: result.data.id })
-            } else {
-              toast.show({ message: "Failed to fork session", variant: "error" })
-            }
-          })
-        } else {
-          route.navigate({
-            type: "session",
-            sessionID: args.sessionID,
-          })
-        }
+      // Handle --session without --fork immediately (fork is handled in createEffect below)
+      if (args.sessionID && !args.fork) {
+        route.navigate({
+          type: "session",
+          sessionID: args.sessionID,
+        })
       }
     })
   })
@@ -289,6 +280,22 @@ function App() {
     }
   })
 
+  // Handle --session with --fork: wait for sync to be fully complete before forking
+  // (session list loads in non-blocking phase for --session, so we must wait for "complete"
+  // to avoid a race where reconcile overwrites the newly forked session)
+  let forked = false
+  createEffect(() => {
+    if (forked || sync.status !== "complete" || !args.sessionID || !args.fork) return
+    forked = true
+    sdk.client.session.fork({ sessionID: args.sessionID }).then((result) => {
+      if (result.data?.id) {
+        route.navigate({ type: "session", sessionID: result.data.id })
+      } else {
+        toast.show({ message: "Failed to fork session", variant: "error" })
+      }
+    })
+  })
+
   createEffect(
     on(
       () => sync.status === "complete" && sync.data.provider.length === 0,