diff --git a/docs/nix.md b/docs/nix.md
new file mode 100644
index 00000000..bf1685e1
--- /dev/null
+++ b/docs/nix.md
@@ -0,0 +1,74 @@
+# Nix package
+
+INSOMNIA provides a flake package for installing the user-facing Pod CLI and TUI binaries without relying on a source checkout at runtime.
+
+## Build
+
+From the repository root:
+
+```sh
+nix build .#
+```
+
+The default package is implemented by `package.nix` and builds the Cargo workspace binaries `pod` and `tui`. The derivation uses the checked-in `Cargo.lock`, so Cargo dependencies are fetched by the normal Nix Rust packaging path instead of by network access during the build.
+
+The package output contains:
+
+- `bin/pod` — Pod CLI / runtime process.
+- `bin/tui` — terminal UI.
+- `share/insomnia/resources/` — bundled runtime resources, including `resources/prompts/`.
+- `share/doc/insomnia/nix.md` — this document.
+
+## Run
+
+After `nix build`:
+
+```sh
+./result/bin/pod --help
+./result/bin/tui
+```
+
+With flakes:
+
+```sh
+nix run .#tui
+nix run .#pod -- --help
+```
+
+`nix run .#` defaults to the TUI.
+
+## Configuration discovery
+
+The Nix package does not put user configuration, sessions, sockets, or other mutable state in the Nix store. The installed binaries keep the same path semantics as non-Nix builds:
+
+| Purpose | Override | `INSOMNIA_HOME` fallback | XDG / default fallback |
+| --- | --- | --- | --- |
+| User config (`manifest.toml`, prompt overrides, model/provider overrides) | `INSOMNIA_CONFIG_DIR` | `$INSOMNIA_HOME/config` | `$XDG_CONFIG_HOME/insomnia`, then `$HOME/.config/insomnia` |
+| Persistent data (`sessions/`, Pod metadata) | `INSOMNIA_DATA_DIR` | `$INSOMNIA_HOME` | `$HOME/.insomnia` |
+| Runtime state (sockets, lock files, live registry) | `INSOMNIA_RUNTIME_DIR` | `$INSOMNIA_HOME/run` | `$XDG_RUNTIME_DIR/insomnia`, then `$HOME/.insomnia/run` |
+
+`INSOMNIA_USER_MANIFEST=<path>` can still be used to select an explicit user manifest for the Pod CLI cascade path. Project manifests are still discovered from `.insomnia/manifest.toml` under the current workspace unless a CLI mode documents otherwise.
+
+## Validation
+
+The package derivation has a credential-free install check that verifies:
+
+- `pod --help` starts successfully.
+- `tui` is installed and reaches argument parsing.
+- bundled prompt resources and this Nix usage document are present in the output.
+
+For full validation before handing changes to review, run:
+
+```sh
+nix build .#
+nix flake check
+cargo fmt --check
+```
+
+This packaging change does not require provider credentials. A Rust `cargo check` is only needed if Rust source or runtime path semantics are changed.
+
+## Known limitations
+
+- The package currently installs the TUI and Pod CLI only; development-only wrappers from `devshell.nix` are not part of the installable package.
+- The TUI does not currently expose a conventional `--help` / `--version` CLI path, so the package smoke check uses an argument-parse failure path for the TUI rather than launching an interactive session.
+- Bundled resources are installed under `share/insomnia/resources/` for packaging completeness and inspection. Built-in prompt/resource loading remains governed by the existing application code and user/project override rules.
diff --git a/flake.nix b/flake.nix
index 0f493fb7..38b62d8c 100644
--- a/flake.nix
+++ b/flake.nix
@@ -1,5 +1,5 @@
 {
-  description = "A very basic flake";
+  description = "INSOMNIA agent runtime";
 
   inputs = {
     nixpkgs.url = "github:nixos/nixpkgs?ref=nixos-unstable";
@@ -16,9 +16,22 @@
       system:
       let
         pkgs = nixpkgs.legacyPackages.${system};
+        insomnia = pkgs.callPackage ./package.nix { };
+        mkApp = name: description: {
+          type = "app";
+          program = "${insomnia}/bin/${name}";
+          meta.description = description;
+        };
       in
       {
-        packages.default = pkgs.callPackage ./package.nix { };
+        packages.default = insomnia;
+        packages.insomnia = insomnia;
+
+        apps.default = mkApp "tui" "Run the INSOMNIA terminal UI";
+        apps.tui = mkApp "tui" "Run the INSOMNIA terminal UI";
+        apps.pod = mkApp "pod" "Run the INSOMNIA Pod CLI";
+
+        checks.default = insomnia;
 
         devShells.default = import ./devshell.nix { inherit pkgs; };
       }
diff --git a/package.nix b/package.nix
index e69de29b..1e050bd0 100644
--- a/package.nix
+++ b/package.nix
@@ -0,0 +1,97 @@
+{
+  lib,
+  stdenv,
+  rustPlatform,
+  pkg-config,
+  openssl,
+  darwin,
+}:
+
+let
+  srcRoot = ./.;
+  srcRootString = toString srcRoot;
+  sourceFilter =
+    path: type:
+    let
+      pathString = toString path;
+      relPath = lib.removePrefix "${srcRootString}/" pathString;
+      baseName = baseNameOf pathString;
+    in
+    !(
+      baseName == ".git"
+      || baseName == "target"
+      || baseName == "result"
+      || lib.hasPrefix ".insomnia" relPath
+      || lib.hasPrefix "work-items" relPath
+    );
+in
+rustPlatform.buildRustPackage rec {
+  pname = "insomnia";
+  version = "0.1.0";
+
+  src = lib.cleanSourceWith {
+    src = srcRoot;
+    filter = sourceFilter;
+  };
+
+  cargoLock.lockFile = ./Cargo.lock;
+
+  strictDeps = true;
+
+  nativeBuildInputs = [ pkg-config ];
+
+  buildInputs = [
+    openssl
+  ]
+  ++ lib.optionals stdenv.hostPlatform.isDarwin (
+    with darwin.apple_sdk.frameworks;
+    [
+      CoreFoundation
+      Security
+      SystemConfiguration
+    ]
+  );
+
+  cargoBuildFlags = [
+    "-p"
+    "pod"
+    "-p"
+    "tui"
+  ];
+
+  # The package check is a credential-free install smoke check below. Running the
+  # workspace test suite is intentionally left to cargo-based CI because this
+  # derivation is scoped to packaging the user-facing binaries.
+  doCheck = false;
+
+  postInstall = ''
+    install -Dm644 docs/nix.md "$out/share/doc/insomnia/nix.md"
+    mkdir -p "$out/share/insomnia"
+    cp -R resources "$out/share/insomnia/resources"
+  '';
+
+  doInstallCheck = true;
+  installCheckPhase = ''
+    runHook preInstallCheck
+
+    "$out/bin/pod" --help >/dev/null
+    test -x "$out/bin/tui"
+    if "$out/bin/tui" --session not-a-uuid 2>tui.err; then
+      echo "tui unexpectedly accepted an invalid --session value" >&2
+      exit 1
+    fi
+    grep -q "invalid --session UUID" tui.err
+
+    test -d "$out/share/insomnia/resources/prompts"
+    test -f "$out/share/doc/insomnia/nix.md"
+
+    runHook postInstallCheck
+  '';
+
+  meta = {
+    description = "Agentic coding Pod runtime and terminal UI";
+    license = lib.licenses.mit;
+    mainProgram = "tui";
+    platforms = lib.platforms.unix;
+  };
+}