diff --git a/script/install.d/01-ssh.sh b/script/install.d/01-ssh.sh
index dfbc454..b8292e2 100644
--- a/script/install.d/01-ssh.sh
+++ b/script/install.d/01-ssh.sh
@@ -5,7 +5,7 @@
 #   Print SSH key.
 #
 
-# Skip in Codespaces
+# Skip in Codespaces (managed by GitHub)
 [[ "$DOTS_ENV" == "codespaces" ]] && { log_pass "Skipping in Codespaces"; return 0; }
 
 # Skip if explicitly disabled
diff --git a/script/install.d/03-apt.sh b/script/install.d/03-apt.sh
index 51e954c..a40414b 100644
--- a/script/install.d/03-apt.sh
+++ b/script/install.d/03-apt.sh
@@ -5,6 +5,9 @@
 #   (distros with apt only) Install core apt packages.
 #
 
+# Skip in Codespaces (pre-installed in universal image)
+[[ "$DOTS_ENV" == "codespaces" ]] && { log_pass "Skipping in Codespaces"; return 0; }
+
 # apt only
 [[ "$DOTS_PKG" != "apt" ]] && { log_warn "Skipping: Not using apt"; return 0; }
 
diff --git a/script/install.d/04-git.sh b/script/install.d/04-git.sh
index 06ccf44..79993d0 100644
--- a/script/install.d/04-git.sh
+++ b/script/install.d/04-git.sh
@@ -5,6 +5,9 @@
 #   Configure git.
 #
 
+# Skip in Codespaces (pre-installed in universal image)
+[[ "$DOTS_ENV" == "codespaces" ]] && { log_pass "Skipping in Codespaces"; git --version; return 0; }
+
 if ! command -v git &> /dev/null; then
     case "$DOTS_PKG" in
         apt)
diff --git a/script/install.d/10-pyenv.sh b/script/install.d/10-pyenv.sh
index 6ca5843..2b4ca36 100644
--- a/script/install.d/10-pyenv.sh
+++ b/script/install.d/10-pyenv.sh
@@ -5,6 +5,9 @@
 #   Configure pyenv.
 #
 
+# Skip in Codespaces (use pre-installed Python)
+[[ "$DOTS_ENV" == "codespaces" ]] && { log_pass "Skipping in Codespaces"; return 0; }
+
 export PYENV_ROOT="$HOME/.pyenv"
 if ! echo "$PATH" | grep -q "$PYENV_ROOT"; then
     export PATH="$PYENV_ROOT/bin:$PATH"
diff --git a/script/install.d/11-python.sh b/script/install.d/11-python.sh
index a8e5a63..72cbabd 100644
--- a/script/install.d/11-python.sh
+++ b/script/install.d/11-python.sh
@@ -5,6 +5,9 @@
 #   Configure Python.
 #
 
+# Skip in Codespaces (use pre-installed Python)
+[[ "$DOTS_ENV" == "codespaces" ]] && { log_pass "Skipping in Codespaces"; return 0; }
+
 export PYTHON_KEYRING_BACKEND=keyring.backends.null.Keyring
 
 local version="3.14.2"
diff --git a/script/install.d/12-node.sh b/script/install.d/12-node.sh
index 79c5431..e458161 100644
--- a/script/install.d/12-node.sh
+++ b/script/install.d/12-node.sh
@@ -5,6 +5,9 @@
 #   Configure Node.js.
 #
 
+# Skip in Codespaces (use pre-installed Node.js)
+[[ "$DOTS_ENV" == "codespaces" ]] && { log_pass "Skipping in Codespaces"; return 0; }
+
 NVM_DIR=${NVM_DIR:-"$HOME/.nvm"}
 [ -s "$NVM_DIR/nvm.sh" ] && source "$NVM_DIR/nvm.sh"
 
diff --git a/script/install.d/21-azure.sh b/script/install.d/21-azure.sh
index 4018580..ab51531 100644
--- a/script/install.d/21-azure.sh
+++ b/script/install.d/21-azure.sh
@@ -5,6 +5,9 @@
 #  Install Azure CLI.
 #
 
+# Skip in Codespaces (project-specific tool)
+[[ "$DOTS_ENV" == "codespaces" ]] && { log_pass "Skipping in Codespaces"; return 0; }
+
 if ! command -v az &>/dev/null; then
     case "$DOTS_PKG" in
         apt)
diff --git a/script/install.d/22-gh.sh b/script/install.d/22-gh.sh
index e172e4c..8d7888a 100644
--- a/script/install.d/22-gh.sh
+++ b/script/install.d/22-gh.sh
@@ -5,6 +5,9 @@
 #   Install GitHub CLI.
 #
 
+# Skip in Codespaces (pre-installed in universal image)
+[[ "$DOTS_ENV" == "codespaces" ]] && { log_pass "Skipping in Codespaces"; return 0; }
+
 if ! command -v gh &>/dev/null; then
     case "$DOTS_PKG" in
         apt)
diff --git a/script/install.d/25-terraform.sh b/script/install.d/25-terraform.sh
index 41745f6..1a1bf4c 100644
--- a/script/install.d/25-terraform.sh
+++ b/script/install.d/25-terraform.sh
@@ -5,6 +5,9 @@
 #   Install terraform.
 #
 
+# Skip in Codespaces (project-specific tool)
+[[ "$DOTS_ENV" == "codespaces" ]] && { log_pass "Skipping in Codespaces"; return 0; }
+
 if ! command -v terraform &>/dev/null; then
     case "$DOTS_PKG" in
         apt)
diff --git a/script/install.d/50-redis.sh b/script/install.d/50-redis.sh
index 10c4f9a..8d2fdc6 100644
--- a/script/install.d/50-redis.sh
+++ b/script/install.d/50-redis.sh
@@ -5,6 +5,9 @@
 #   Install Redis.
 #
 
+# Skip in Codespaces (project-specific tool)
+[[ "$DOTS_ENV" == "codespaces" ]] && { log_pass "Skipping in Codespaces"; return 0; }
+
 if ! command -v redis-cli &>/dev/null; then
     case "$DOTS_PKG" in
         apt)
diff --git a/script/install.d/80-neofetch.sh b/script/install.d/80-neofetch.sh
index 701d341..131cd5f 100644
--- a/script/install.d/80-neofetch.sh
+++ b/script/install.d/80-neofetch.sh
@@ -5,6 +5,9 @@
 #   Install neofetch.
 #
 
+# Skip in Codespaces (cosmetic tool)
+[[ "$DOTS_ENV" == "codespaces" ]] && { log_pass "Skipping in Codespaces"; return 0; }
+
 if ! command -v neofetch &>/dev/null; then
     case "$DOTS_PKG" in
         apt)
diff --git a/script/install.d/98-clean.sh b/script/install.d/98-clean.sh
index 2383ba6..141f4bb 100644
--- a/script/install.d/98-clean.sh
+++ b/script/install.d/98-clean.sh
@@ -5,6 +5,9 @@
 #   Clean up after installation.
 #
 
+# Skip in Codespaces (minimal benefit in ephemeral environment)
+[[ "$DOTS_ENV" == "codespaces" ]] && { log_pass "Skipping in Codespaces"; return 0; }
+
 case "$DOTS_PKG" in
     brew)
         brew cleanup
diff --git a/script/install.d/99-screenfetch.sh b/script/install.d/99-screenfetch.sh
index 912f0d1..a3bef8c 100644
--- a/script/install.d/99-screenfetch.sh
+++ b/script/install.d/99-screenfetch.sh
@@ -5,4 +5,7 @@
 #   Print system information.
 #
 
+# Skip in Codespaces (cosmetic only)
+[[ "$DOTS_ENV" == "codespaces" ]] && { log_pass "Skipping in Codespaces"; return 0; }
+
 neofetch