diff --git a/.envrc b/.envrc
index cc5c18b..bf3c4ec 100644
--- a/.envrc
+++ b/.envrc
@@ -2,11 +2,65 @@
 
 export DIRENV_WARN_TIMEOUT=20s
 
-eval "$(devenv direnvrc)"
+# Backend selection:
+# - default: use devenv when available, otherwise Guix
+# - optional local override: write "guix" or "devenv" to .dev-shell
+backend=auto
+if [ -f .dev-shell ]; then
+  backend=$(tr -d '[:space:]' < .dev-shell)
+  watch_file .dev-shell
+fi
 
-# `use devenv` supports the same options as the `devenv shell` command.
-#
-# To silence all output, use `--quiet`.
-#
-# Example usage: use devenv --quiet --impure --option services.postgres.enable:bool true
-use devenv
+use_aether_guix() {
+  watch_file guix-dev.scm
+  watch_file .pre-commit-config.yaml
+  watch_file scripts/plugin
+  watch_file "$HOME/guix-tribes/tribes/packages/devtools.scm"
+  watch_file "$HOME/guix-tribes/tribes/packages/node.scm"
+
+  use guix -L "$HOME/guix-tribes" -m guix-dev.scm
+
+  if [ -f .env ]; then set -a; . ./.env; set +a; fi
+  export MIX_OS_DEPS_COMPILE_PARTITION_COUNT=8
+  export NODE_ENV=development
+  export NPM_CONFIG_MIN_RELEASE_AGE=7
+  export TRIBES_HOST_ROOT="${TRIBES_HOST_ROOT:-$PWD/../tribes}"
+
+  plugin() { bash "$PWD/scripts/plugin" "$@"; }
+}
+
+use_aether_devenv() {
+  eval "$(devenv direnvrc)"
+  use devenv
+}
+
+case "$backend" in
+  auto)
+    if command -v devenv >/dev/null 2>&1; then
+      use_aether_devenv
+    elif command -v guix >/dev/null 2>&1; then
+      use_aether_guix
+    else
+      log_error "neither devenv nor guix is available"
+      exit 1
+    fi
+    ;;
+  nix|devenv)
+    if ! command -v devenv >/dev/null 2>&1; then
+      log_error ".dev-shell requested devenv, but devenv is unavailable"
+      exit 1
+    fi
+    use_aether_devenv
+    ;;
+  guix)
+    if ! command -v guix >/dev/null 2>&1; then
+      log_error ".dev-shell requested guix, but guix is unavailable"
+      exit 1
+    fi
+    use_aether_guix
+    ;;
+  *)
+    log_error "unknown .dev-shell backend: $backend"
+    exit 1
+    ;;
+esac
diff --git a/.gitignore b/.gitignore
index eb97c29..51453be 100644
--- a/.gitignore
+++ b/.gitignore
@@ -39,9 +39,8 @@ Thumbs.db
 .env
 .null-ls_*.nix
 devenv.local.nix
+.guix-dev/
+.dev-shell
 
 # direnv
 .direnv
-
-# pre-commit
-.pre-commit-config.yaml
diff --git a/.pre-commit-config.yaml b/.pre-commit-config.yaml
new file mode 100644
index 0000000..15be2ff
--- /dev/null
+++ b/.pre-commit-config.yaml
@@ -0,0 +1,34 @@
+# Shared by Nix/devenv and Guix shells. Keep hook entries PATH-based.
+default_stages:
+  - pre-commit
+
+repos:
+  - repo: local
+    hooks:
+      - id: check-added-large-files
+        name: check added large files
+        entry: scripts/hooks/check-added-large-files
+        args: ["--maxkb=131072"]
+        language: system
+        types: [file]
+        stages: [pre-commit, pre-push, manual]
+
+      - id: mix-format
+        name: mix format
+        entry: mix format
+        language: system
+        files: '\.(ex|exs|heex)$'
+        types: [file]
+        stages: [pre-commit]
+
+      - id: prettier
+        name: prettier
+        entry: prettier
+        args:
+          - --ignore-unknown
+          - --list-different
+          - --write
+        language: system
+        files: '\.(js|ts|tsx|css)$'
+        types: [text]
+        stages: [pre-commit]
diff --git a/guix-dev.scm b/guix-dev.scm
new file mode 100644
index 0000000..3215add
--- /dev/null
+++ b/guix-dev.scm
@@ -0,0 +1,39 @@
+;; Guix development manifest for the Aether plugin.
+;;
+;; Usage:
+;;   guix shell -L ~/guix-tribes -m guix-dev.scm
+;;
+;; This intentionally keeps the repo-specific development package list here,
+;; similar to devenv.nix.  Shared custom packages such as node-24, prek, and
+;; prettier come from the local guix-tribes channel.
+
+(use-modules (gnu packages bash)
+             (gnu packages base)
+             (gnu packages elixir)
+             (gnu packages erlang)
+             (gnu packages gnome)
+             (gnu packages linux)
+             (gnu packages nss)
+             (gnu packages version-control)
+             (guix profiles)
+             (tribes packages devtools)
+             ((tribes packages node) #:select (node-24)))
+
+(packages->manifest
+ (list bash
+       coreutils
+       findutils
+       grep
+       sed
+       nss-certs
+       git
+       pre-commit
+       prek
+       prettier
+       erlang
+       elixir
+       elixir-hex
+       rebar3
+       node-24
+       libnotify
+       inotify-tools))
diff --git a/scripts/hooks/check-added-large-files b/scripts/hooks/check-added-large-files
new file mode 100755
index 0000000..b46fa23
--- /dev/null
+++ b/scripts/hooks/check-added-large-files
@@ -0,0 +1,38 @@
+#!/usr/bin/env sh
+set -eu
+
+maxkb=500
+while [ "$#" -gt 0 ]; do
+  case "$1" in
+    --maxkb=*)
+      maxkb=${1#--maxkb=}
+      shift
+      ;;
+    --)
+      shift
+      break
+      ;;
+    -*)
+      echo "check-added-large-files: unknown option: $1" >&2
+      exit 2
+      ;;
+    *)
+      break
+      ;;
+  esac
+done
+
+limit=$((maxkb * 1024))
+failed=0
+
+for file in "$@"; do
+  [ -f "$file" ] || continue
+  size=$(wc -c < "$file" | tr -d '[:space:]')
+  if [ "$size" -gt "$limit" ]; then
+    kb=$(((size + 1023) / 1024))
+    echo "$file (${kb} KB) exceeds ${maxkb} KB" >&2
+    failed=1
+  fi
+done
+
+exit "$failed"