fix(claude-code): address PR review feedback for yoloAlias

Make alias appending idempotent with grep guard, add security warning
to docs, and strengthen test assertions to verify full command string.

Author: tmaier

src/claude-code/NOTES.md

@@ -17,6 +17,10 @@ The channel chosen at install time becomes the default for auto-updates.
 
 When `yoloAlias` is set to `true`, a `yolo` shell alias is created that expands to `claude --allow-dangerously-skip-permissions`. The alias is configured for bash, zsh, and fish.
 
+> **Warning:** `--allow-dangerously-skip-permissions` disables Claude Code's normal permission checks and confirmation prompts for potentially sensitive actions. This meaningfully reduces safety and may allow unintended or unsafe changes, so only enable `yoloAlias` if you understand and accept the security implications.
+>
+> Creating this alias may also override an existing `yolo` alias in your shell configuration.
+
 ## Auto-Updates
 
 The native binary automatically updates in the background. Update checks are performed on startup and periodically while running. To disable auto-updates, set the `DISABLE_AUTOUPDATER=1` environment variable.

src/claude-code/install.sh

@@ -59,11 +59,25 @@ if [ "${YOLOALIAS:-false}" = "true" ]; then
     ALIAS_CMD='alias yolo="claude --allow-dangerously-skip-permissions"'
     TARGET_HOME="${INSTALL_HOME}"
 
+    add_shell_alias_if_missing() {
+        local rc_file="$1"
+        local alias_name="$2"
+        local alias_cmd="$3"
+
+        if [ -f "$rc_file" ] && grep -Eq "^[[:space:]]*alias[[:space:]]+${alias_name}=" "$rc_file"; then
+            echo "Skipping $rc_file: alias '$alias_name' already exists."
+            return 0
+        fi
+
+        touch "$rc_file"
+        printf '%s\n' "$alias_cmd" >> "$rc_file"
+    }
+
     # bash
-    echo "$ALIAS_CMD" >> "$TARGET_HOME/.bashrc"
+    add_shell_alias_if_missing "$TARGET_HOME/.bashrc" "yolo" "$ALIAS_CMD"
 
     # zsh
-    echo "$ALIAS_CMD" >> "$TARGET_HOME/.zshrc"
+    add_shell_alias_if_missing "$TARGET_HOME/.zshrc" "yolo" "$ALIAS_CMD"
 
     # fish — create a function file (idiomatic for fish)
     FISH_FUNC_DIR="$TARGET_HOME/.config/fish/functions"

test/claude-code/claude_code_yolo_alias.sh

@@ -10,9 +10,9 @@ source dev-container-features-test-lib
 
 # Feature-specific tests
 check "claude command available" which claude
-check "yolo alias in bashrc" bash -c "grep -q 'alias yolo=' ~/.bashrc"
-check "yolo alias in zshrc" bash -c "grep -q 'alias yolo=' ~/.zshrc"
-check "fish yolo function exists" bash -c "test -f ~/.config/fish/functions/yolo.fish"
+check "yolo alias in bashrc" bash -c "grep -Fq 'claude --allow-dangerously-skip-permissions' ~/.bashrc"
+check "yolo alias in zshrc" bash -c "grep -Fq 'claude --allow-dangerously-skip-permissions' ~/.zshrc"
+check "fish yolo function body" bash -c "test -f ~/.config/fish/functions/yolo.fish && grep -Fq 'claude --allow-dangerously-skip-permissions' ~/.config/fish/functions/yolo.fish"
 check "yolo resolves in bash" bash -ic "type yolo"
 
 # Report results