diff --git a/pkgs/development/python-modules/langgraph-cli/default.nix b/pkgs/development/python-modules/langgraph-cli/default.nix
index faaab1ce7e80..f395d6b61d2c 100644
--- a/pkgs/development/python-modules/langgraph-cli/default.nix
+++ b/pkgs/development/python-modules/langgraph-cli/default.nix
@@ -8,7 +8,10 @@
 
   # dependencies
   click,
+  langgraph,
+  langgraph-runtime-inmem,
   langgraph-sdk,
+  python-dotenv,
 
   # testing
   pytest-asyncio,
@@ -40,21 +43,20 @@ buildPythonPackage rec {
     langgraph-sdk
   ];
 
-  # Not yet. Depemnds on `langgraph-runtime-inmem` which isn't in github yet
-  # https://github.com/langchain-ai/langgraph/issues/5802
-  # optional-dependencies = {
-  #   "inmem" = [
-  #     langgraph-api
-  #     langgraph-runtime-inmem
-  #     python-dotenv
-  #   ]
-  # }
+  optional-dependencies = {
+    "inmem" = [
+      langgraph
+      langgraph-runtime-inmem
+      python-dotenv
+    ];
+  };
 
   nativeCheckInputs = [
     pytest-asyncio
     pytestCheckHook
     docker-compose
-  ];
+  ]
+  ++ lib.flatten (builtins.attrValues optional-dependencies);
 
   enabledTestPaths = [ "tests/unit_tests" ];
 
diff --git a/pkgs/development/python-modules/langgraph-runtime-inmem/default.nix b/pkgs/development/python-modules/langgraph-runtime-inmem/default.nix
index 3dd52a5f6c7b..87d660138956 100644
--- a/pkgs/development/python-modules/langgraph-runtime-inmem/default.nix
+++ b/pkgs/development/python-modules/langgraph-runtime-inmem/default.nix
@@ -23,14 +23,6 @@ buildPythonPackage rec {
     hash = "sha256-chPmwJ+tUJoRK5xX9+r6mbYf95ZbX4Z3mP6Ra19nBxM=";
   };
 
-  # 1.5.24 (now 1.5.25) only affects non-cpython builds
-  # upgrade: https://github.com/NixOS/nixpkgs/pull/431547
-  postPatch = ''
-    substituteInPlace pyproject.toml \
-      --replace "blockbuster>=1.5.24,<2.0.0" \
-     "blockbuster>=1.5.23,<2.0.0"
-  '';
-
   build-system = [
     hatchling
   ];
@@ -44,6 +36,12 @@ buildPythonPackage rec {
     structlog
   ];
 
+  # Can remove after blockbuster version bump
+  # https://github.com/NixOS/nixpkgs/pull/431547
+  pythonRelaxDeps = [
+    "blockbuster"
+  ];
+
   pythonImportsCheck = [
     "langgraph_runtime_inmem"
   ];