fix(nix): make hermes in developement environment actually work

install modules as editable overlay with uv

.envrc

@@ -1,4 +1,4 @@
-watch_file pyproject.toml uv.lock
+watch_file pyproject.toml uv.lock hermes
 watch_file package-lock.json package.json web/package.json ui-tui/package.json website/package.json apps/shared/package.json apps/desktop/package.json ui-tui/packages/hermes-ink/package.json
 watch_file flake.nix flake.lock nix/devShell.nix nix/tui.nix nix/package.nix nix/python.nix nix/hermes-agent.nix nix/desktop.nix
 

nix/devShell.nix

@@ -28,13 +28,20 @@
         packages =
           with pkgs;
           [
+            (pkgs.runCommand "hermes" { } ''
+              mkdir -p $out/bin
+              install -Dm755 ${../hermes} $out/bin/hermes
+            '')
             uv
           ]
           ++ self'.packages.default.passthru.devDeps;
         shellHook = ''
-          echo "Hermes Agent dev shell"
           ${combinedNonNpm}
           ${hermesNpmLib.mkNpmDevShellHook npmPackageJsonPaths}
+
+          # for the devshell to pick up the src
+          export HERMES_PYTHON_SRC_ROOT=$(git rev-parse --show-toplevel)
+          echo "Hermes Agent dev shell in $HERMES_PYTHON_SRC_ROOT"
           echo "Ready. Run 'hermes' to start."
         '';
       };

nix/hermes-agent.nix

@@ -44,7 +44,7 @@ let
       dependency-groups = [ "all" ] ++ extraDependencyGroups;
     };
 
-  hermesVenv = mkHermesVenv extraDependencyGroups;
+  hermesVenv = (mkHermesVenv extraDependencyGroups).venv;
 
   hermesNpmLib = callPackage ./lib.nix {
     inherit npm-lockfile-fix nodejs;
@@ -200,33 +200,37 @@ stdenv.mkDerivation (finalAttrs: {
     runHook postInstall
   '';
 
-  passthru = {
-    inherit
-      hermesTui
-      hermesWeb
-      hermesNpmLib
-      hermesVenv
-      ;
+  passthru =
+    let
+      devPython = (mkHermesVenv (extraDependencyGroups ++ [ "dev" ])).editableVenv;
+    in
+    {
+      inherit
+        hermesTui
+        hermesWeb
+        hermesNpmLib
+        hermesVenv
+        ;
 
-    # `hermesDesktop` references `finalAttrs.finalPackage` (this whole
-    # derivation, after all overrides are applied) so the desktop wrapper
-    # can prepend its `/bin` to PATH.  The desktop's resolver step 4
-    # ("existing hermes on PATH") then picks up the fully wrapped
-    # `hermes` binary — venv with all deps, bundled skills/plugins,
-    # runtime PATH (ripgrep/git/ffmpeg/etc).  No re-implementation
-    # of the agent resolution in the desktop wrapper.
-    hermesDesktop = callPackage ./desktop.nix {
-      inherit hermesNpmLib electron;
-      hermesAgent = finalAttrs.finalPackage;
+      # `hermesDesktop` references `finalAttrs.finalPackage` (this whole
+      # derivation, after all overrides are applied) so the desktop wrapper
+      # can prepend its `/bin` to PATH.  The desktop's resolver step 4
+      # ("existing hermes on PATH") then picks up the fully wrapped
+      # `hermes` binary — venv with all deps, bundled skills/plugins,
+      # runtime PATH (ripgrep/git/ffmpeg/etc).  No re-implementation
+      # of the agent resolution in the desktop wrapper.
+      hermesDesktop = callPackage ./desktop.nix {
+        inherit hermesNpmLib electron;
+        hermesAgent = finalAttrs.finalPackage;
+      };
+
+      devShellHook = ''
+        export HERMES_PYTHON=${devPython}/bin/python3
+      '';
+
+      devDeps = runtimeDeps ++ [ devPython ];
     };
 
-    devShellHook = ''
-      export HERMES_PYTHON=${hermesVenv}/bin/python3
-    '';
-
-    devDeps = runtimeDeps ++ [ (mkHermesVenv (extraDependencyGroups ++ [ "dev" ])) ];
-  };
-
   meta = with lib; {
     description = "AI agent with advanced tool-calling capabilities";
     homepage = "https://github.com/NousResearch/hermes-agent";

nix/python.nix

@@ -27,7 +27,8 @@ let
     dependency-groups = { };
   };
 
-  mkPrebuiltOverride = final: from: dependencies:
+  mkPrebuiltOverride =
+    final: from: dependencies:
     hacks.nixpkgsPrebuilt {
       inherit from;
       prev = {
@@ -38,64 +39,100 @@ let
 
   # Legacy alibabacloud packages ship only sdists with setup.py/setup.cfg
   # and no pyproject.toml, so setuptools isn't declared as a build dep.
-  buildSystemOverrides = final: prev: builtins.mapAttrs
-    (name: _: prev.${name}.overrideAttrs (old: {
-      nativeBuildInputs = (old.nativeBuildInputs or [ ]) ++ [ final.setuptools ];
-    }))
-    (lib.genAttrs [
-      "alibabacloud-credentials-api"
-      "alibabacloud-endpoint-util"
-      "alibabacloud-gateway-dingtalk"
-      "alibabacloud-gateway-spi"
-      "alibabacloud-tea"
-    ] (_: null));
+  buildSystemOverrides =
+    final: prev:
+    builtins.mapAttrs
+      (
+        name: _:
+        prev.${name}.overrideAttrs (old: {
+          nativeBuildInputs = (old.nativeBuildInputs or [ ]) ++ [ final.setuptools ];
+        })
+      )
+      (
+        lib.genAttrs [
+          "alibabacloud-credentials-api"
+          "alibabacloud-endpoint-util"
+          "alibabacloud-gateway-dingtalk"
+          "alibabacloud-gateway-spi"
+          "alibabacloud-tea"
+        ] (_: null)
+      );
 
-  pythonPackageOverrides = final: _prev:
-    if isAarch64Darwin then {
-      numpy = mkPrebuiltOverride final python312.pkgs.numpy { };
+  pythonPackageOverrides =
+    final: _prev:
+    if isAarch64Darwin then
+      {
+        numpy = mkPrebuiltOverride final python312.pkgs.numpy { };
 
-      pyarrow = mkPrebuiltOverride final python312.pkgs.pyarrow { };
+        pyarrow = mkPrebuiltOverride final python312.pkgs.pyarrow { };
 
-      av = mkPrebuiltOverride final python312.pkgs.av { };
+        av = mkPrebuiltOverride final python312.pkgs.av { };
 
-      humanfriendly = mkPrebuiltOverride final python312.pkgs.humanfriendly { };
+        humanfriendly = mkPrebuiltOverride final python312.pkgs.humanfriendly { };
 
-      coloredlogs = mkPrebuiltOverride final python312.pkgs.coloredlogs {
-        humanfriendly = [ ];
-      };
+        coloredlogs = mkPrebuiltOverride final python312.pkgs.coloredlogs {
+          humanfriendly = [ ];
+        };
 
-      onnxruntime = mkPrebuiltOverride final python312.pkgs.onnxruntime {
-        coloredlogs = [ ];
-        numpy = [ ];
-        packaging = [ ];
-      };
+        onnxruntime = mkPrebuiltOverride final python312.pkgs.onnxruntime {
+          coloredlogs = [ ];
+          numpy = [ ];
+          packaging = [ ];
+        };
 
-      ctranslate2 = mkPrebuiltOverride final python312.pkgs.ctranslate2 {
-        numpy = [ ];
-        pyyaml = [ ];
-      };
+        ctranslate2 = mkPrebuiltOverride final python312.pkgs.ctranslate2 {
+          numpy = [ ];
+          pyyaml = [ ];
+        };
 
-      faster-whisper = mkPrebuiltOverride final python312.pkgs.faster-whisper {
-        av = [ ];
-        ctranslate2 = [ ];
-        huggingface-hub = [ ];
-        onnxruntime = [ ];
-        tokenizers = [ ];
-        tqdm = [ ];
-      };
-    } else {};
+        faster-whisper = mkPrebuiltOverride final python312.pkgs.faster-whisper {
+          av = [ ];
+          ctranslate2 = [ ];
+          huggingface-hub = [ ];
+          onnxruntime = [ ];
+          tokenizers = [ ];
+          tqdm = [ ];
+        };
+      }
+    else
+      { };
 
   pythonSet =
     (callPackage pyproject-nix.build.packages {
       python = python312;
     }).overrideScope
-      (lib.composeManyExtensions [
-        pyproject-build-systems.overlays.default
-        overlay
-        buildSystemOverrides
-        pythonPackageOverrides
-      ]);
+      (
+        lib.composeManyExtensions [
+          pyproject-build-systems.overlays.default
+          overlay
+          buildSystemOverrides
+          pythonPackageOverrides
+        ]
+      );
+
+  editableOverlay = workspace.mkEditablePyprojectOverlay {
+    root = "$HERMES_PYTHON_SRC_ROOT"; # resolved at shellHook time
+  };
+
+  workspaceRoot = ./..;
+  editableSet = pythonSet.overrideScope (
+    lib.composeManyExtensions [
+      editableOverlay
+      (final: prev: {
+        hermes-agent = prev.hermes-agent.overrideAttrs (old: {
+          # point straight at the real source instead of the filtered nix store copy
+          src = workspaceRoot;
+          nativeBuildInputs = old.nativeBuildInputs ++ final.resolveBuildSystem { editables = [ ]; };
+        });
+      })
+    ]
+  );
 in
-pythonSet.mkVirtualEnv "hermes-agent-env" {
-  hermes-agent = dependency-groups;
+{
+  venv = pythonSet.mkVirtualEnv "hermes-agent-env" {
+    hermes-agent = dependency-groups;
+  };
+  editableVenv = editableSet.mkVirtualEnv "hermes-agent-editable-env" {
+    hermes-agent = dependency-groups;
+  };
 }