diff --git a/pkgs/by-name/bu/buzz-cli/package.nix b/pkgs/by-name/bu/buzz-cli/package.nix
new file mode 100644
index 000000000000..a320b4990a03
--- /dev/null
+++ b/pkgs/by-name/bu/buzz-cli/package.nix
@@ -0,0 +1,49 @@
+{
+  cacert,
+  fetchFromGitHub,
+  lib,
+  rustPlatform,
+  stdenv,
+}:
+
+rustPlatform.buildRustPackage {
+  pname = "buzz-cli";
+  version = "0.1.0-unstable-2026-08-27";
+  __structuredAttrs = true;
+  __darwinAllowLocalNetworking = true;
+  strictDeps = true;
+
+  src = fetchFromGitHub {
+    owner = "block";
+    repo = "buzz";
+    rev = "0808ab485c39c3c12ef02af2188c65a5145eb99d";
+    hash = "sha256-+vYRX6yZmyWxtpcaQj62ujmcG2uwo3fdaX5Oo6Q1jEE=";
+  };
+
+  cargoHash = "sha256-y067FJWvsJAe6mvtnLPSW1YK0/gcBrKuZX45OCO8/2U=";
+  cargoBuildFlags = [ "--package=buzz-cli" ];
+  cargoTestFlags = [ "--package=buzz-cli" ];
+
+  # reqwest initializes its rustls client in tests and needs a CA bundle.
+  nativeCheckInputs = [ cacert ];
+
+  env = lib.optionalAttrs (stdenv.hostPlatform.isDarwin && stdenv.hostPlatform.isAarch64) {
+    # Avoid nondeterministic LC_UUIDs emitted by ld64 on arm64.
+    RUSTFLAGS = "-C link-arg=-Wl,-no_uuid";
+  };
+
+  preBuild = ''
+    # Remap transient Nix build paths for reproducible output.
+    export RUSTFLAGS="--remap-path-prefix=$NIX_BUILD_TOP=/build ''${RUSTFLAGS:-}"
+    export NIX_CFLAGS_COMPILE="-ffile-prefix-map=$NIX_BUILD_TOP=/build ''${NIX_CFLAGS_COMPILE:-}"
+  '';
+
+  meta = {
+    description = "Agent-first CLI for Buzz relay";
+    homepage = "https://github.com/block/buzz";
+    license = lib.licenses.asl20;
+    mainProgram = "buzz";
+    maintainers = [ lib.maintainers.sebfried ];
+    platforms = lib.platforms.linux ++ lib.platforms.darwin;
+  };
+}