diff --git a/README.md b/README.md
index 09580e1..0f52e48 100644
--- a/README.md
+++ b/README.md
@@ -104,9 +104,28 @@ Studio remains on the ThinkPads as an existing IDE/workflow choice, but its
 bundled SDK is worth reviewing if moving fully to project-local tooling.
 
 Codex CLI (`codex`) and Claude Code (`claude`) are installed on every host.
-Run each command as your normal user and follow its sign-in flow. Update these
-Nix-managed packages through the flake and rebuild rather than their standalone
-installers. Authentication stays in your home directory, outside this repo.
+Run each command as your normal user and follow its sign-in flow.
+They use official upstream binaries, with versions and SHA-256 checksums pinned
+in `packages/ai-cli-versions.json`, independently of the stable NixOS release.
+`packages/ai-cli.nix` packages Codex and reuses Nixpkgs' Claude Code wrapper.
+Authentication stays in your home directory, outside this repo.
+
+To update both to the latest stable upstream releases, run from this repo:
+
+```sh
+nix shell nixpkgs#python3 -c python3 scripts/update-ai-cli.py
+git diff -- packages/ai-cli-versions.json
+nix build .#codex .#claude-code --no-link
+sudo nixos-rebuild switch --flake .#framework
+codex --version
+claude --version
+git add packages/ai-cli-versions.json
+git commit -m "chore(ai-cli): update upstream releases"
+```
+
+Use your own host name when rebuilding. The updater changes only the CLI pins;
+`nix flake update` updates NixOS inputs but does not update these pins.
+Updates remain explicit and reproducible; no upstream self-updaters are used.
 
 The official ChatGPT Linux desktop preview does not formally support NixOS.
 Our pinned `chatgpt` package supports macOS only, so it is not installed here.
diff --git a/flake.nix b/flake.nix
index 0b400a9..4d20efb 100644
--- a/flake.nix
+++ b/flake.nix
@@ -19,6 +19,14 @@
       ...
     }:
     {
+      # Build the CLI packages separately before switching a host.
+      packages.x86_64-linux = import ./packages/ai-cli.nix {
+        pkgs = import nixpkgs {
+          system = "x86_64-linux";
+          config.allowUnfree = true;
+        };
+      };
+
       nixosConfigurations = {
         t450s = nixpkgs.lib.nixosSystem {
           specialArgs.unstable = import nixpkgs-unstable {
diff --git a/modules/development.nix b/modules/development.nix
index 056f583..2e6b1d7 100644
--- a/modules/development.nix
+++ b/modules/development.nix
@@ -1,4 +1,7 @@
 { pkgs, ... }:
+let
+  aiCli = import ../packages/ai-cli.nix { inherit pkgs; };
+in
 {
   # Workstation tools only; language runtimes and SDKs belong in projects.
   environment.systemPackages = with pkgs; [
@@ -19,8 +22,8 @@
     zip
 
     # Coding assistants; authenticate separately as your normal user.
-    codex
-    claude-code
+    aiCli.codex
+    aiCli.claude-code
 
     # Infrastructure, containers, and structured data.
     ansible
diff --git a/packages/ai-cli-versions.json b/packages/ai-cli-versions.json
new file mode 100644
index 0000000..ccb08d0
--- /dev/null
+++ b/packages/ai-cli-versions.json
@@ -0,0 +1,10 @@
+{
+  "codex": {
+    "version": "0.161.0",
+    "sha256": "04d8ab9dbcb9df0edf3c67dca5072a374babfdf762a9bc4ae649ae140b8e2cf0"
+  },
+  "claude-code": {
+    "version": "2.1.292",
+    "sha256": "a967e7b1d8b4e47ee421d5433027880347952b0c0857abf880e2c942a4ec93b3"
+  }
+}
diff --git a/packages/ai-cli.nix b/packages/ai-cli.nix
new file mode 100644
index 0000000..3ab060e
--- /dev/null
+++ b/packages/ai-cli.nix
@@ -0,0 +1,53 @@
+{ pkgs }:
+let
+  versions = builtins.fromJSON (builtins.readFile ./ai-cli-versions.json);
+in
+{
+  # Use the complete official package, including Code Mode and voice helpers.
+  codex = pkgs.stdenvNoCC.mkDerivation {
+    pname = "codex";
+    inherit (versions.codex) version;
+    src = pkgs.fetchurl {
+      url = "https://github.com/openai/codex/releases/download/rust-v${versions.codex.version}/codex-package-x86_64-unknown-linux-musl.tar.gz";
+      inherit (versions.codex) sha256;
+    };
+    sourceRoot = ".";
+    nativeBuildInputs = [ pkgs.autoPatchelfHook pkgs.makeWrapper ];
+    buildInputs = [ pkgs.glibc pkgs.ncurses ];
+    dontBuild = true;
+    dontStrip = true;
+
+    installPhase = ''
+      runHook preInstall
+      mkdir -p "$out"
+      cp -r bin codex-path codex-resources codex-package.json "$out/"
+      runHook postInstall
+    '';
+    postFixup = ''
+      wrapProgram "$out/bin/codex" \
+        --prefix PATH : ${pkgs.lib.makeBinPath [ pkgs.ripgrep pkgs.bubblewrap ]}
+    '';
+    doInstallCheck = true;
+    installCheckPhase = ''
+      runHook preInstallCheck
+      "$out/bin/codex" --version | grep -F "codex-cli ${versions.codex.version}"
+      runHook postInstallCheck
+    '';
+    meta = {
+      description = "OpenAI coding agent, official upstream binary package";
+      homepage = "https://github.com/openai/codex";
+      license = pkgs.lib.licenses.asl20;
+      mainProgram = "codex";
+      platforms = [ "x86_64-linux" ];
+      sourceProvenance = [ pkgs.lib.sourceTypes.binaryNativeCode ];
+    };
+  };
+
+  # Keep Nixpkgs' NixOS compatibility fixes and sandbox dependencies.
+  claude-code = pkgs.claude-code.override {
+    manifest = {
+      inherit (versions.claude-code) version;
+      platforms.linux-x64.checksum = versions.claude-code.sha256;
+    };
+  };
+}
diff --git a/scripts/update-ai-cli.py b/scripts/update-ai-cli.py
new file mode 100644
index 0000000..a63e9cf
--- /dev/null
+++ b/scripts/update-ai-cli.py
@@ -0,0 +1,57 @@
+#!/usr/bin/env python3
+"""Pin the latest stable upstream CLI releases without updating NixOS."""
+
+import json
+import re
+import urllib.request
+from pathlib import Path
+
+
+def fetch_json(url):
+    request = urllib.request.Request(
+        url, headers={"User-Agent": "nixos-config-ai-cli-updater"}
+    )
+    with urllib.request.urlopen(request, timeout=60) as response:
+        return json.load(response)
+
+
+def latest_release(repository):
+    release = fetch_json(f"https://api.github.com/repos/{repository}/releases/latest")
+    if release["prerelease"] or release["draft"]:
+        raise ValueError(f"Expected a stable release from {repository}")
+    return release
+
+
+codex = latest_release("openai/codex")
+codex_version = codex["tag_name"].removeprefix("rust-v")
+claude = latest_release("anthropics/claude-code")
+claude_version = claude["tag_name"].removeprefix("v")
+for version in (codex_version, claude_version):
+    if not re.fullmatch(r"\d+\.\d+\.\d+", version):
+        raise ValueError(f"Unexpected release version: {version}")
+
+asset = next(
+    item for item in codex["assets"]
+    if item["name"] == "codex-package-x86_64-unknown-linux-musl.tar.gz"
+)
+digest = asset["digest"]
+if not re.fullmatch(r"sha256:[0-9a-f]{64}", digest):
+    raise ValueError("Codex release asset has no valid SHA-256 digest")
+
+manifest = fetch_json(
+    f"https://downloads.claude.ai/claude-code-releases/{claude_version}/manifest.json"
+)
+if manifest["version"] != claude_version:
+    raise ValueError("Claude release and download manifest versions differ")
+claude_hash = manifest["platforms"]["linux-x64"]["checksum"]
+if not re.fullmatch(r"[0-9a-f]{64}", claude_hash):
+    raise ValueError("Claude manifest has no valid SHA-256 checksum")
+
+versions = {
+    "codex": {"version": codex_version, "sha256": digest.removeprefix("sha256:")},
+    "claude-code": {"version": claude_version, "sha256": claude_hash},
+}
+destination = Path(__file__).resolve().parent.parent / "packages" / "ai-cli-versions.json"
+destination.write_text(json.dumps(versions, indent=2) + "\n")
+print(f"Pinned Codex {codex_version} and Claude Code {claude_version}.")
+print("Review the diff, build the packages, rebuild your host and commit the pins.")