diff --git a/mcp_server/cli.py b/mcp_server/cli.py
index ac716e5..d64deec 100644
--- a/mcp_server/cli.py
+++ b/mcp_server/cli.py
@@ -266,7 +266,7 @@ async def cmd_retry_generation(args: argparse.Namespace) -> int:
     print(f"Using project root: {root}")
     set_project_root(root)
 
-    generation_id = resolve_generation_id(None, root)
+    generation_id = resolve_generation_id(args.generation_id, root)
     if not generation_id:
         print("No previous generation found. Run `specflow run-generation` to start one.")
         return 0
@@ -564,7 +564,13 @@ def _build_parser() -> argparse.ArgumentParser:
     subparsers.add_parser("check-status", help="Check progress of a running generation")
 
     # retry-generation
-    subparsers.add_parser("retry-generation", help="Retry a failed generation")
+    p_retry = subparsers.add_parser("retry-generation", help="Retry a failed generation")
+    p_retry.add_argument(
+        "--generation-id",
+        default=None,
+        dest="generation_id",
+        help="Generation ID (default: from specflow_session.json)",
+    )
 
     # download-outputs
     p_dl = subparsers.add_parser(
diff --git a/mcp_server/tests/test_cli.py b/mcp_server/tests/test_cli.py
index 9c93c75..b64e39a 100644
--- a/mcp_server/tests/test_cli.py
+++ b/mcp_server/tests/test_cli.py
@@ -283,7 +283,7 @@ async def test_calls_retry_endpoint(self, tmp_project):
         from services.session import write_session
         write_session("gen-xyz", tmp_project)
 
-        args = SimpleNamespace(root_path=str(tmp_project), command="retry-generation")
+        args = SimpleNamespace(root_path=str(tmp_project), command="retry-generation", generation_id=None)
 
         # check_status_safe returns failed → proceed to retry POST
         with patch(
@@ -308,7 +308,7 @@ async def test_blocks_when_already_running(self, tmp_project, capsys):
         from services.session import write_session
         write_session("gen-running", tmp_project)
 
-        args = SimpleNamespace(root_path=str(tmp_project), command="retry-generation")
+        args = SimpleNamespace(root_path=str(tmp_project), command="retry-generation", generation_id=None)
 
         with patch(
             "services.tool_helpers.check_status_safe",
diff --git a/mcp_server/tests/test_tui_app.py b/mcp_server/tests/test_tui_app.py
index 7b70857..07aabfb 100644
--- a/mcp_server/tests/test_tui_app.py
+++ b/mcp_server/tests/test_tui_app.py
@@ -1136,13 +1136,13 @@ async def test_retry_runs_action_when_confirmed(self):
                     patch.object(app, "push_screen_wait", new=AsyncMock(return_value=True)),
                     patch.object(screen, "_run_suspended", new=AsyncMock()) as run_susp,
                     # do_retry is async; force a sync mock so the flow's
-                    # ``do_retry(root)`` yields a sentinel, not a live coroutine.
+                    # ``do_retry(root, generation_id)`` yields a sentinel, not a live coroutine.
                     patch(
                         "tui.app.actions.do_retry", new=MagicMock(return_value="retry-coro")
                     ) as do_retry,
                 ):
                     await screen._retry_flow()
-                do_retry.assert_called_once_with(app.root)
+                do_retry.assert_called_once_with(app.root, "gen_x")
                 run_susp.assert_awaited_once_with("retry-coro")
 
     @pytest.mark.asyncio
diff --git a/mcp_server/tui/actions.py b/mcp_server/tui/actions.py
index d9ec9b7..556a32c 100644
--- a/mcp_server/tui/actions.py
+++ b/mcp_server/tui/actions.py
@@ -44,9 +44,11 @@ def _ns(**overrides: object) -> SimpleNamespace:
     return SimpleNamespace(**base)
 
 
-async def do_retry(root: Path) -> int:
+async def do_retry(root: Path, generation_id: str | None = None) -> int:
     """Retry the current generation (reuses ``cmd_retry_generation`` guards)."""
-    return await cli.cmd_retry_generation(_ns(root_path=str(root)))
+    return await cli.cmd_retry_generation(
+        _ns(root_path=str(root), generation_id=generation_id)
+    )
 
 
 async def do_clear_set(set_number: int) -> int:
diff --git a/mcp_server/tui/app.py b/mcp_server/tui/app.py
index c909ad5..243c00e 100644
--- a/mcp_server/tui/app.py
+++ b/mcp_server/tui/app.py
@@ -628,7 +628,7 @@ async def _retry_flow(self) -> None:
             )
         )
         if ok:
-            await self._run_suspended(actions.do_retry(self.app.root))
+            await self._run_suspended(actions.do_retry(self.app.root, self._generation_id))
 
     def action_clear(self) -> None:
         self.run_worker(self._clear_flow(), exclusive=True)