diff --git a/flake.lock b/flake.lock
index ea38c54..f6f514a 100644
--- a/flake.lock
+++ b/flake.lock
@@ -14,9 +14,81 @@
         "url": "https://flakehub.com/f/NixOS/nixpkgs/0"
       }
     },
+    "pyproject-build-systems": {
+      "inputs": {
+        "nixpkgs": [
+          "nixpkgs"
+        ],
+        "pyproject-nix": [
+          "pyproject-nix"
+        ],
+        "uv2nix": [
+          "uv2nix"
+        ]
+      },
+      "locked": {
+        "lastModified": 1782093830,
+        "narHash": "sha256-6gmEVe69+KlRkZD4PEEV5xAlB9CB0Y9TiuEgQjDrKTQ=",
+        "owner": "pyproject-nix",
+        "repo": "build-system-pkgs",
+        "rev": "430680a19bc85a3bda55f12e4cc1a1aadcf2e478",
+        "type": "github"
+      },
+      "original": {
+        "owner": "pyproject-nix",
+        "repo": "build-system-pkgs",
+        "type": "github"
+      }
+    },
+    "pyproject-nix": {
+      "inputs": {
+        "nixpkgs": [
+          "nixpkgs"
+        ]
+      },
+      "locked": {
+        "lastModified": 1782089418,
+        "narHash": "sha256-LRD1SuQWr49fGq3A+8GLXfsLE2xqIpQA440YDZwms3M=",
+        "owner": "pyproject-nix",
+        "repo": "pyproject.nix",
+        "rev": "43f0b40edd0a74c63f66b7b48d969ae6b740d611",
+        "type": "github"
+      },
+      "original": {
+        "owner": "pyproject-nix",
+        "repo": "pyproject.nix",
+        "type": "github"
+      }
+    },
     "root": {
       "inputs": {
-        "nixpkgs": "nixpkgs"
+        "nixpkgs": "nixpkgs",
+        "pyproject-build-systems": "pyproject-build-systems",
+        "pyproject-nix": "pyproject-nix",
+        "uv2nix": "uv2nix"
+      }
+    },
+    "uv2nix": {
+      "inputs": {
+        "nixpkgs": [
+          "nixpkgs"
+        ],
+        "pyproject-nix": [
+          "pyproject-nix"
+        ]
+      },
+      "locked": {
+        "lastModified": 1782100052,
+        "narHash": "sha256-UfyLY3Hfwb3JqxCcj0953GxTFI5dEL85EKEe6DAFiVs=",
+        "owner": "pyproject-nix",
+        "repo": "uv2nix",
+        "rev": "920fc6dfaf9f10ec56de93b184055e1a9f380d5e",
+        "type": "github"
+      },
+      "original": {
+        "owner": "pyproject-nix",
+        "repo": "uv2nix",
+        "type": "github"
       }
     }
   },
diff --git a/flake.nix b/flake.nix
index 0354f7d..569aae1 100644
--- a/flake.nix
+++ b/flake.nix
@@ -1,10 +1,31 @@
 {
   description = "Tartarus: a Nix-defined containment runtime for auditable agents";
 
-  inputs.nixpkgs.url = "https://flakehub.com/f/NixOS/nixpkgs/0";
+  inputs = {
+    nixpkgs.url = "https://flakehub.com/f/NixOS/nixpkgs/0";
+
+    # uv2nix turns uv.lock into a Nix Python package set, so the harness's Python
+    # deps are resolved from the lockfile rather than hand-maintained.
+    pyproject-nix.url = "github:pyproject-nix/pyproject.nix";
+    pyproject-nix.inputs.nixpkgs.follows = "nixpkgs";
+    uv2nix.url = "github:pyproject-nix/uv2nix";
+    uv2nix.inputs.pyproject-nix.follows = "pyproject-nix";
+    uv2nix.inputs.nixpkgs.follows = "nixpkgs";
+    # uv does not lock build systems; this overlay supplies backends (hatchling).
+    pyproject-build-systems.url = "github:pyproject-nix/build-system-pkgs";
+    pyproject-build-systems.inputs.pyproject-nix.follows = "pyproject-nix";
+    pyproject-build-systems.inputs.uv2nix.follows = "uv2nix";
+    pyproject-build-systems.inputs.nixpkgs.follows = "nixpkgs";
+  };
 
   outputs =
-    { nixpkgs, ... }:
+    {
+      nixpkgs,
+      pyproject-nix,
+      uv2nix,
+      pyproject-build-systems,
+      ...
+    }:
     let
       supportedSystems = [
         "x86_64-linux"
@@ -34,13 +55,28 @@
         agentsLib.mkAgents { inherit pkgs packages; } (import ./agent.nix { inherit pkgs; })
       );
 
-      # The developer shell for hacking on this harness (Python + pytest). This is
-      # distinct from an agent's own `shell`, whose PATH is baked into its bundle.
-      devShells = eachSystem (
+      # The packaged harness (uv2nix virtualenv). `nix build .#tartarus` /
+      # `nix run .#tartarus -- "prompt"`. See package.nix.
+      packages = eachSystem (
         system:
         let
           pkgs = pkgsFor system;
+          tartarus = pkgs.callPackage ./package.nix {
+            inherit pyproject-nix uv2nix pyproject-build-systems;
+          };
         in
+        {
+          default = tartarus;
+          inherit tartarus;
+        }
+      );
+
+      # The developer shell for hacking on this harness (Python + pytest). This
+      # is distinct from an agent's own `shell`, whose PATH is baked into its
+      # bundle. ruff and ty are supplied by `uv`, not this shell.
+      devShells = eachSystem (
+        system:
+        let pkgs = pkgsFor system; in
         {
           default = pkgs.mkShellNoCC {
             packages = with pkgs; [
@@ -52,10 +88,10 @@
               nixfmt
               ripgrep
               gnused
-              (python3.withPackages (pythonPackages: [
-                pythonPackages.httpx
-                pythonPackages.pip
-                pythonPackages.pytest
+              (python3.withPackages (p: [
+                p.httpx
+                p.pip
+                p.pytest
               ]))
             ];
           };
diff --git a/package.nix b/package.nix
new file mode 100644
index 0000000..d3e85ec
--- /dev/null
+++ b/package.nix
@@ -0,0 +1,34 @@
+# Package the tartarus harness from uv.lock via uv2nix.
+{
+  pkgs,
+  lib,
+  pyproject-nix,
+  uv2nix,
+  pyproject-build-systems,
+}:
+
+let
+  workspace = uv2nix.lib.workspace.loadWorkspace { workspaceRoot = ./.; };
+
+  python =
+    let
+      interpreters = pyproject-nix.lib.util.filterPythonInterpreters {
+        inherit (workspace) requires-python;
+        inherit (pkgs) pythonInterpreters;
+      };
+    in
+    if interpreters == [ ] then
+      throw "tartarus: no Python interpreter matches requires-python = \"${workspace.requires-python}\""
+    else
+      builtins.elemAt interpreters 0;
+
+  pythonSet = (pkgs.callPackage pyproject-nix.build.packages { inherit python; }).overrideScope (
+    lib.composeManyExtensions [
+      pyproject-build-systems.overlays.wheel
+      (workspace.mkPyprojectOverlay { sourcePreference = "wheel"; })
+    ]
+  );
+in
+(pythonSet.mkVirtualEnv "tartarus-env" workspace.deps.default).overrideAttrs (_: {
+  meta.mainProgram = "tartarus";
+})
diff --git a/pyproject.toml b/pyproject.toml
index 130a641..9538764 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -1,13 +1,20 @@
+[build-system]
+requires = ["hatchling"]
+build-backend = "hatchling.build"
+
 [project]
 name = "tartarus-nix"
 version = "0.1.0"
-description = "A Nix-defined containment runtime for auditable agents."
+description = "A framework for building composable, hermetic, and shareable AI agents with Nix."
 readme = "README.md"
 requires-python = ">=3.13"
 dependencies = [
     "httpx>=0.28.1",
 ]
 
+[project.scripts]
+tartarus = "tartarus.cli:main"
+
 [dependency-groups]
 dev = [
     "pytest>=9.1.1",
@@ -18,3 +25,6 @@ dev = [
 [tool.pytest.ini_options]
 pythonpath = ["."]
 testpaths = ["tests"]
+
+[tool.hatch.build.targets.wheel]
+packages = ["tartarus"]
diff --git a/uv.lock b/uv.lock
index 4cda813..76d9758 100644
--- a/uv.lock
+++ b/uv.lock
@@ -2,31 +2,6 @@ version = 1
 revision = 3
 requires-python = ">=3.13"
 
-[[package]]
-name = "tartarus-nix"
-version = "0.1.0"
-source = { virtual = "." }
-dependencies = [
-    { name = "httpx" },
-]
-
-[package.dev-dependencies]
-dev = [
-    { name = "pytest" },
-    { name = "ruff" },
-    { name = "ty" },
-]
-
-[package.metadata]
-requires-dist = [{ name = "httpx", specifier = ">=0.28.1" }]
-
-[package.metadata.requires-dev]
-dev = [
-    { name = "pytest", specifier = ">=9.1.1" },
-    { name = "ruff", specifier = ">=0.15.20" },
-    { name = "ty", specifier = ">=0.0.55" },
-]
-
 [[package]]
 name = "anyio"
 version = "4.14.1"
@@ -180,6 +155,31 @@ wheels = [
     { url = "https://files.pythonhosted.org/packages/d7/2b/9555445e1201d92b3195f45cdb153a0b68f24e0a4273f6e3d5ab46e212bb/ruff-0.15.20-py3-none-win_arm64.whl", hash = "sha256:2f5b2a6d614e8700388806a14996c40fab2c47b819ef57d790a34878858ed9ca", size = 11343498, upload-time = "2026-06-25T17:20:35.03Z" },
 ]
 
+[[package]]
+name = "tartarus-nix"
+version = "0.1.0"
+source = { editable = "." }
+dependencies = [
+    { name = "httpx" },
+]
+
+[package.dev-dependencies]
+dev = [
+    { name = "pytest" },
+    { name = "ruff" },
+    { name = "ty" },
+]
+
+[package.metadata]
+requires-dist = [{ name = "httpx", specifier = ">=0.28.1" }]
+
+[package.metadata.requires-dev]
+dev = [
+    { name = "pytest", specifier = ">=9.1.1" },
+    { name = "ruff", specifier = ">=0.15.20" },
+    { name = "ty", specifier = ">=0.0.55" },
+]
+
 [[package]]
 name = "ty"
 version = "0.0.55"