diff --git a/.zshrc b/.zshrc
index 31db0e5..68f9bb9 100644
--- a/.zshrc
+++ b/.zshrc
@@ -137,6 +137,9 @@ man() {
 # sheldon
 eval "$(sheldon source)"
 
+# direnv: auto-load per-directory environments (e.g. Nix devShells via .envrc)
+eval "$(direnv hook zsh)"
+
 # The next line updates PATH for the Google Cloud SDK.
 if [ -f '/Users/naoki/google-cloud-sdk/path.zsh.inc' ]; then . '/Users/naoki/google-cloud-sdk/path.zsh.inc'; fi
 
diff --git a/Brewfile b/Brewfile
index 464a54a..40543b6 100644
--- a/Brewfile
+++ b/Brewfile
@@ -2,6 +2,7 @@ tap "aquaproj/aqua"
 tap "gcenx/wine"
 tap "playcover/playcover"
 brew "aqua"
+brew "bash"
 brew "clang-format"
 brew "cmake"
 brew "ffmpeg"
diff --git a/aqua/aqua-checksums.json b/aqua/aqua-checksums.json
index 2aee0ec..3325ab6 100644
--- a/aqua/aqua-checksums.json
+++ b/aqua/aqua-checksums.json
@@ -30,6 +30,36 @@
       "checksum": "A341BF9E1074A1586C2CE3E0E46685C1722B4C99A4699B34A906E3A47E3885E5",
       "algorithm": "sha256"
     },
+    {
+      "id": "github_release/github.com/direnv/direnv/v2.37.1/direnv.darwin-amd64",
+      "checksum": "24FB9CE48B563D7E9FBDD3A4E3E836941654A31CE3E67EBA9EAAFC3DCD8AE73B",
+      "algorithm": "sha256"
+    },
+    {
+      "id": "github_release/github.com/direnv/direnv/v2.37.1/direnv.darwin-arm64",
+      "checksum": "4F569F3A36732BFD8B8FEA7BFCC6AD87A59745C109022164D0CA4832451D5369",
+      "algorithm": "sha256"
+    },
+    {
+      "id": "github_release/github.com/direnv/direnv/v2.37.1/direnv.linux-amd64",
+      "checksum": "1F1B93DD6F38523FDE26DFAC96151EF9D31A374E3005CD3345FB93555AE0C9B5",
+      "algorithm": "sha256"
+    },
+    {
+      "id": "github_release/github.com/direnv/direnv/v2.37.1/direnv.linux-arm64",
+      "checksum": "2A9CEF8D73521D6A3EC3F2871C4B747B8C4CC038628C1B57A7EFA42B393A2D82",
+      "algorithm": "sha256"
+    },
+    {
+      "id": "github_release/github.com/direnv/direnv/v2.37.1/direnv.windows-amd64",
+      "checksum": "D96FC8B7CF020C2D4C1DBBC2CCEC5FD1CAB05B51C491F02C8527A7FA6C50A1CD",
+      "algorithm": "sha256"
+    },
+    {
+      "id": "github_release/github.com/direnv/direnv/v2.37.1/direnv.windows-arm64",
+      "checksum": "6802F722F5EF12562D6E3E15C26F39E34B337E5BE12EA22F17284552CD782298",
+      "algorithm": "sha256"
+    },
     {
       "id": "github_release/github.com/evilmartians/lefthook/v2.1.6/lefthook_2.1.6_Linux_aarch64.gz",
       "checksum": "F85CC031DA8E3571418170AB53F1E6E184A086B58683E13660BD5248974159A4",
diff --git a/aqua/imports/direnv.yaml b/aqua/imports/direnv.yaml
new file mode 100644
index 0000000..7afd3f5
--- /dev/null
+++ b/aqua/imports/direnv.yaml
@@ -0,0 +1,2 @@
+packages:
+  - name: direnv/direnv@v2.37.1
diff --git a/direnv/direnvrc b/direnv/direnvrc
new file mode 100644
index 0000000..4c8388c
--- /dev/null
+++ b/direnv/direnvrc
@@ -0,0 +1,6 @@
+# nix-direnv: caches `use flake` evaluation and pins build deps as gcroots so
+# they survive garbage collection. Loaded globally so each project's .envrc
+# stays a bare `use flake`. Pinned by version + checksum.
+if ! has nix_direnv_version || ! nix_direnv_version 3.1.2; then
+  source_url "https://raw.githubusercontent.com/nix-community/nix-direnv/3.1.2/direnvrc" "sha256-Di03ad3a0ueGi6CGrfhrQzyGdQIg9APXIPCAMNQgWYM="
+fi
diff --git a/install.sh b/install.sh
index cd65ac2..8823eb5 100755
--- a/install.sh
+++ b/install.sh
@@ -44,6 +44,7 @@ mkdir -p ~/.config/aqua
 mkdir -p ~/.config/ghostty/themes
 mkdir -p ~/.config/sheldon
 mkdir -p ~/.config/nvim
+mkdir -p ~/.config/direnv
 mkdir -p ~/.local/share/sheldon
 mkdir -p ~/.cursor
 mkdir -p ~/.claude
@@ -80,6 +81,7 @@ ln -sfn "$DOTFILES_DIR/ghostty/themes/kanagawa-wave" ~/.config/ghostty/themes/ka
 ln -sfn "$DOTFILES_DIR/sheldon/plugins.toml" ~/.config/sheldon/plugins.toml
 ln -sfn "$DOTFILES_DIR/sheldon/plugins.lock" ~/.local/share/sheldon/plugins.lock
 ln -sfn "$DOTFILES_DIR/nvim" ~/.config/nvim
+ln -sfn "$DOTFILES_DIR/direnv/direnvrc" ~/.config/direnv/direnvrc
 
 echo "✓ Symlinks created"