diff --git a/.claude/settings.local.json b/.claude/settings.local.json
new file mode 100644
index 0000000..6041c46
--- /dev/null
+++ b/.claude/settings.local.json
@@ -0,0 +1,14 @@
+{
+  "permissions": {
+    "allow": [
+      "Bash(fish_indent:*)",
+      "Bash(find:*)",
+      "Bash(make lint-fish:*)",
+      "Bash(make lint-json:*)",
+      "Bash(make lint-markdown:*)",
+      "Bash(make lint-fix:*)",
+      "Bash(make lint:*)"
+    ],
+    "deny": []
+  }
+}
\ No newline at end of file
diff --git a/.editorconfig b/.editorconfig
index 869f880..864816a 100644
--- a/.editorconfig
+++ b/.editorconfig
@@ -3,17 +3,9 @@ root = true
 [*]
 charset = utf-8
 end_of_line = lf
-indent_size = 2
-indent_style = space
 insert_final_newline = true
-max_line_length = 160
-tab_width = 2
 trim_trailing_whitespace = true
 
-[{*.json}]
+[*.fish]
 indent_size = 4
-tab_width = 4
-
-[{*.markdown,*.md}]
-indent_size = 4
-tab_width = 4
+indent_style = space
diff --git a/.github/workflows/lint.yml b/.github/workflows/lint.yml
new file mode 100644
index 0000000..4a267e1
--- /dev/null
+++ b/.github/workflows/lint.yml
@@ -0,0 +1,47 @@
+name: Lint
+
+on:
+    push:
+        branches: [main, develop]
+    pull_request:
+        branches: [main, develop]
+
+jobs:
+    lint:
+        runs-on: ubuntu-latest
+        name: Lint codebase
+
+        steps:
+            - name: Checkout code
+              uses: actions/checkout@11bd71901bbe5b1630ceea73d27597364c9af683 # v4.2.2
+
+            - name: Setup Node.js
+              uses: actions/setup-node@49933ea5288caeca8642d1e84afbd3f7d6820020 # v4.4.0
+              with:
+                  node-version: '18'
+                  cache: 'npm'
+
+            - name: Setup Fish shell
+              run: |
+                  sudo apt-add-repository ppa:fish-shell/release-3
+                  sudo apt-get update
+                  sudo apt-get install -y fish
+
+            - name: Install linting tools
+              run: make install-tools
+
+            - name: Lint Fish files
+              run: make lint-fish
+
+            - name: Lint Markdown files
+              run: make lint-markdown
+
+            - name: Lint JSON files
+              run: make lint-json
+
+            - name: Test plugin installation
+              shell: fish {0}
+              run: |
+                  curl -sL https://raw.githubusercontent.com/jorgebucaran/fisher/main/functions/fisher.fish | source && fisher install jorgebucaran/fisher
+                  fisher --version
+                  make test
diff --git a/.github/workflows/pr-lint.yml b/.github/workflows/pr-lint.yml
index 193995c..2167179 100644
--- a/.github/workflows/pr-lint.yml
+++ b/.github/workflows/pr-lint.yml
@@ -15,4 +15,4 @@ permissions:
 
 jobs:
   SuperLinter:
-    uses: ivuorinen/actions/pr-lint@main
+    uses: ivuorinen/actions/pr-lint@625c37446b1c7e219755a40807f825c9283f6e05 # 25.7.7
diff --git a/.github/workflows/stale.yml b/.github/workflows/stale.yml
index 2055b92..58f6e3c 100644
--- a/.github/workflows/stale.yml
+++ b/.github/workflows/stale.yml
@@ -16,4 +16,4 @@ jobs:
       issues: write
       pull-requests: write
     steps:
-      - uses: ivuorinen/actions/stale@main
+      - uses: ivuorinen/actions/stale@625c37446b1c7e219755a40807f825c9283f6e05 # 25.7.7
diff --git a/.github/workflows/sync-labels.yml b/.github/workflows/sync-labels.yml
index e5e2001..c5c6856 100644
--- a/.github/workflows/sync-labels.yml
+++ b/.github/workflows/sync-labels.yml
@@ -20,4 +20,4 @@ jobs:
       issues: write
     runs-on: ubuntu-latest
     steps:
-      - uses: ivuorinen/actions/sync-labels@main
+      - uses: ivuorinen/actions/sync-labels@625c37446b1c7e219755a40807f825c9283f6e05 # 25.7.7
diff --git a/.markdownlint.json b/.markdownlint.json
new file mode 100644
index 0000000..2b178f5
--- /dev/null
+++ b/.markdownlint.json
@@ -0,0 +1,7 @@
+{
+    "default": true,
+    "MD007": { "indent": 4 },
+    "MD013": { "line_length": 120 },
+    "MD033": false,
+    "MD041": false
+}
\ No newline at end of file
diff --git a/CLAUDE.md b/CLAUDE.md
new file mode 100644
index 0000000..34a900c
--- /dev/null
+++ b/CLAUDE.md
@@ -0,0 +1,119 @@
+# CLAUDE.md
+
+This file provides guidance to Claude Code (claude.ai/code) when working with code in this repository.
+
+## Project Overview
+
+This is a Fish shell plugin that automatically loads the correct Node.js version from `.nvmrc` files when
+changing directories. The plugin uses Fisher as its package manager.
+
+## Architecture
+
+The plugin consists of two main Fish functions:
+
+- `nvm_auto_use.fish` - Main function that triggers on directory changes (`--on-variable PWD`) and handles
+  the automatic Node.js version switching
+- `nvm_find_nvmrc.fish` - Utility function that searches for `.nvmrc` files in the current directory and parent directories
+
+## Development Commands
+
+### Linting and Code Quality
+
+```bash
+# Install all linting tools (markdownlint-cli, jsonlint, jq)
+make install-tools
+
+# Run all linting checks
+make lint
+
+# Fix auto-fixable linting issues
+make lint-fix
+
+# Individual linting commands
+make lint-fish        # Lint Fish shell files
+make lint-markdown    # Lint Markdown files  
+make lint-json        # Lint JSON files
+```
+
+#### Manual Fish Commands
+
+```fish
+# Format all Fish files (required before commits)
+find . -name "*.fish" -exec fish_indent --write {} \;
+
+# Check formatting without modifying files
+find . -name "*.fish" -exec fish_indent --check {} \;
+
+# Validate Fish syntax
+fish -n functions/*.fish completions/*.fish
+```
+
+### Installation/Testing
+
+```bash
+# Test plugin installation using Makefile
+make test
+```
+
+#### Manual Installation Commands
+
+```fish
+# Install the plugin locally for testing
+fisher install .
+
+# Remove the plugin
+fisher remove ivuorinen/nvm-auto-use.fish
+```
+
+### Configuration Commands
+
+```fish
+# View current configuration
+nvm_auto_use_config
+
+# Enable/disable features
+nvm_auto_use_config silent on
+nvm_auto_use_config auto_install off
+nvm_auto_use_config manager fnm
+
+# Set debounce timing
+nvm_auto_use_config debounce 1000
+
+# Exclude directories
+nvm_auto_use_config exclude "build"
+```
+
+### Testing the Functions
+
+```fish
+# Test the nvmrc finder function
+nvm_find_nvmrc
+
+# Test version extraction
+nvm_extract_version .nvmrc
+
+# Test directory change trigger (create a test .nvmrc file)
+echo "18.0.0" > .nvmrc
+cd .  # This should trigger nvm_auto_use
+
+# Check version status
+nvm_version_status
+```
+
+## Key Implementation Details
+
+- The plugin hooks into Fish's variable change system using `--on-variable PWD`
+- Supports multiple Node.js version managers: nvm, fnm, volta, asdf
+- Supports multiple file formats: `.nvmrc`, `.node-version`, `.tool-versions`, `package.json` engines.node
+- Includes performance optimizations: caching, debouncing, directory exclusions
+- Configurable features: silent mode, auto-install toggle, notifications, project-only mode
+- Error handling includes checking if Node.js is available and graceful fallback when versions can't be switched
+- The search for version files traverses up the directory tree until it finds one or reaches the root directory
+
+## Code Quality Standards
+
+- All Fish code must be formatted with `fish_indent` before committing
+- Functions should include description flags (`-d "description"`)
+- Use proper Fish conventions for variable scoping (`set -l`, `set -g`, `set -gx`)
+- Include comprehensive error handling and input validation
+- Follow Fish best practices for command substitution and string handling
diff --git a/Makefile b/Makefile
new file mode 100644
index 0000000..171c5b3
--- /dev/null
+++ b/Makefile
@@ -0,0 +1,137 @@
+# Makefile for nvm-auto-use.fish
+
+.PHONY: help install-tools lint lint-fish lint-markdown lint-json lint-fix lint-check test clean
+
+# Default target
+help:
+	@echo "Available targets:"
+	@echo "  install-tools    - Install all linting tools"
+	@echo "  lint            - Run all linting checks"
+	@echo "  lint-fish       - Lint Fish shell files"
+	@echo "  lint-markdown   - Lint Markdown files"
+	@echo "  lint-json       - Lint JSON files"
+	@echo "  lint-fix        - Fix auto-fixable linting issues"
+	@echo "  lint-check      - Check linting without fixing"
+	@echo "  test            - Run tests (install plugin locally)"
+	@echo "  clean           - Clean temporary files"
+
+# Install all required linting tools
+install-tools:
+	@echo "Installing linting tools..."
+	# Install markdownlint-cli for markdown linting
+	@if ! command -v markdownlint >/dev/null 2>&1; then \
+		echo "Installing markdownlint-cli..."; \
+		npm install -g markdownlint-cli; \
+	else \
+		echo "markdownlint-cli already installed"; \
+	fi
+	# Install jsonlint for JSON linting
+	@if ! command -v jsonlint >/dev/null 2>&1; then \
+		echo "Installing jsonlint..."; \
+		npm install -g jsonlint; \
+	else \
+		echo "jsonlint already installed"; \
+	fi
+	# Install jq for JSON processing (backup)
+	@if ! command -v jq >/dev/null 2>&1; then \
+		echo "Installing jq..."; \
+		if command -v brew >/dev/null 2>&1; then \
+			brew install jq; \
+		elif command -v apt-get >/dev/null 2>&1; then \
+			sudo apt-get install -y jq; \
+		elif command -v yum >/dev/null 2>&1; then \
+			sudo yum install -y jq; \
+		else \
+			echo "Please install jq manually"; \
+		fi; \
+	else \
+		echo "jq already installed"; \
+	fi
+	@echo "All linting tools installed!"
+
+# Run all linting checks
+lint: lint-fish lint-markdown lint-json
+
+# Lint Fish shell files
+lint-fish:
+	@echo "Linting Fish files..."
+	@find . -name "*.fish" -type f | while read -r file; do \
+		echo "Checking $$file..."; \
+		fish_indent --check "$$file" || { \
+			echo "Formatting issues found in $$file"; \
+			exit 1; \
+		}; \
+	done
+	@echo "Validating Fish syntax..."
+	@fish -n functions/*.fish completions/*.fish 2>/dev/null || { \
+		echo "Syntax errors found in Fish files"; \
+		exit 1; \
+	}
+	@echo "Fish files passed linting!"
+
+# Lint Markdown files
+lint-markdown:
+	@echo "Linting Markdown files..."
+	@if command -v markdownlint >/dev/null 2>&1; then \
+		markdownlint --config .markdownlint.json *.md || { \
+			echo "Markdown linting failed"; \
+			exit 1; \
+		}; \
+	else \
+		echo "markdownlint not found, skipping markdown linting"; \
+	fi
+	@echo "Markdown files passed linting!"
+
+# Lint JSON files
+lint-json:
+	@echo "Linting JSON files..."
+	@find . -name "*.json" -type f | while read -r file; do \
+		echo "Checking $$file..."; \
+		if command -v jsonlint >/dev/null 2>&1; then \
+			jsonlint "$$file" >/dev/null || { \
+				echo "JSON syntax error in $$file"; \
+				exit 1; \
+			}; \
+		elif command -v jq >/dev/null 2>&1; then \
+			jq empty "$$file" >/dev/null || { \
+				echo "JSON syntax error in $$file"; \
+				exit 1; \
+			}; \
+		else \
+			echo "No JSON linter found, skipping $$file"; \
+		fi; \
+	done
+	@echo "JSON files passed linting!"
+
+# Fix auto-fixable linting issues
+lint-fix:
+	@echo "Fixing linting issues..."
+	@echo "Formatting Fish files..."
+	@find . -name "*.fish" -type f -exec fish_indent --write {} \;
+	@if command -v markdownlint >/dev/null 2>&1; then \
+		echo "Fixing Markdown files..."; \
+		markdownlint --config .markdownlint.json --fix *.md 2>/dev/null || true; \
+	fi
+	@echo "Linting fixes applied!"
+
+# Check linting without fixing
+lint-check: lint
+
+# Test the plugin by installing it locally
+test:
+	@echo "Testing plugin installation..."
+	@if command -v fisher >/dev/null 2>&1; then \
+		fisher install .; \
+		echo "Plugin installed successfully!"; \
+		echo "Run 'fisher remove ivuorinen/nvm-auto-use.fish' to uninstall"; \
+	else \
+		echo "Fisher not found. Please install Fisher package manager first."; \
+		exit 1; \
+	fi
+
+# Clean temporary files
+clean:
+	@echo "Cleaning temporary files..."
+	@find . -name "*.tmp" -type f -delete 2>/dev/null || true
+	@find . -name ".DS_Store" -type f -delete 2>/dev/null || true
+	@echo "Cleanup complete!"
\ No newline at end of file
diff --git a/README.md b/README.md
index 0d1ff99..dc061c2 100644
--- a/README.md
+++ b/README.md
@@ -1,6 +1,7 @@
 # nvm-auto-use.fish
 
-Automates loading the correct Node.js version from `.nvmrc` in Fish shell.
+Intelligent Node.js version management for Fish shell with automatic version switching, multi-manager support,
+and extensive configuration options.
 
 ## Installation
 
@@ -10,18 +11,122 @@ Ensure you have [fisher](https://github.com/jorgebucaran/fisher) installed, then
 fisher install ivuorinen/nvm-auto-use.fish
 ```
 
-## Usage
+## Features
 
-This script automatically detects the `.nvmrc` file in your current or
-parent directories and loads the specified Node.js version.
+### 🚀 **Automatic Version Switching**
 
-If the specified version is not installed, it will be installed
-automatically using `nvm install`.
+- Detects Node.js version files when changing directories
+- Supports multiple file formats: `.nvmrc`, `.node-version`, `.tool-versions`, `package.json` engines.node
+- Handles version aliases: `lts`, `latest`, `stable`, `node`
+- Automatic version installation when missing
+
+### ⚡ **Performance & UX**
+
+- **Smart caching** - Avoids redundant file reads and version switches
+- **Debouncing** - Prevents rapid switching during quick navigation
+- **Silent mode** - Suppress output messages
+- **Visual indicators** - Display current Node.js version in prompt
+
+### 🔧 **Multi-Manager Compatibility**
+
+- **nvm** - Node Version Manager
+- **fnm** - Fast Node Manager
+- **volta** - JavaScript toolchain manager
+- **asdf** - Extendable version manager
+
+### ⚙️ **Extensive Configuration**
+
+- Toggle automatic installation
+- Directory exclusion patterns
+- Configurable debounce timing
+- Manager preference selection
+- Project-only activation mode
+
+### 🔔 **Developer Tools**
+
+- Desktop notifications for version switches
+- Environment variable export (`NODE_VERSION`)
+- Fish shell completions
+- Detailed status reporting
+
+## Quick Start
+
+After installation, the plugin works automatically! Simply navigate to any directory with a Node.js version file:
+
+```fish
+# Create a project with specific Node version
+echo "18.17.0" > .nvmrc
+cd .  # Automatically switches to Node.js v18.17.0
+
+# Works with package.json too
+echo '{"engines": {"node": ">=16.0.0"}}' > package.json
+cd .  # Switches to compatible Node.js version
+```
+
+## Configuration
+
+Customize the plugin behavior with `nvm_auto_use_config`:
+
+```fish
+# View current settings
+nvm_auto_use_config
+
+# Enable silent mode
+nvm_auto_use_config silent on
+
+# Disable automatic installation
+nvm_auto_use_config auto_install off
+
+# Set preferred version manager
+nvm_auto_use_config manager fnm
+
+# Adjust debounce timing (milliseconds)
+nvm_auto_use_config debounce 1000
+
+# Exclude directories
+nvm_auto_use_config exclude "build"
+nvm_auto_use_config exclude "dist"
+
+# Reset all settings
+nvm_auto_use_config reset
+```
+
+## Supported File Formats
+
+| File | Format | Example |
+|------|--------|---------|
+| `.nvmrc` | Plain version | `18.17.0` or `lts/hydrogen` |
+| `.node-version` | Plain version | `18.17.0` |
+| `.tool-versions` | Tool + version | `nodejs 18.17.0` |
+| `package.json` | engines.node field | `"engines": {"node": ">=16.0.0"}` |
+
+## Utility Functions
+
+```fish
+# Check current Node.js status
+nvm_version_status
+
+# Get version for prompt integration
+nvm_version_prompt  # Returns: ⬢ 18.17.0
+
+# Control silent mode
+nvm_auto_use_silent on/off
+
+# Detect available version managers
+nvm_compat_detect
+```
+
+## Requirements
+
+- Fish shell 3.0+
+- At least one supported Node.js version manager:
+    - [nvm](https://github.com/nvm-sh/nvm)
+    - [fnm](https://github.com/Schniz/fnm)
+    - [volta](https://volta.sh/)
+    - [asdf](https://asdf-vm.com/) with nodejs plugin
 
 ## Uninstall
 
-To remove the plugin, run:
-
 ```fish
 fisher remove ivuorinen/nvm-auto-use.fish
 ```
diff --git a/completions/nvm_auto_use_config.fish b/completions/nvm_auto_use_config.fish
new file mode 100644
index 0000000..33aa5e8
--- /dev/null
+++ b/completions/nvm_auto_use_config.fish
@@ -0,0 +1,27 @@
+# Completions for nvm_auto_use_config
+complete -c nvm_auto_use_config -f
+
+# Main commands
+complete -c nvm_auto_use_config -n "not __fish_seen_subcommand_from auto_install silent debounce exclude include manager reset" -a auto_install -d "Toggle automatic version installation"
+complete -c nvm_auto_use_config -n "not __fish_seen_subcommand_from auto_install silent debounce exclude include manager reset" -a silent -d "Toggle silent mode"
+complete -c nvm_auto_use_config -n "not __fish_seen_subcommand_from auto_install silent debounce exclude include manager reset" -a debounce -d "Set debounce time in milliseconds"
+complete -c nvm_auto_use_config -n "not __fish_seen_subcommand_from auto_install silent debounce exclude include manager reset" -a exclude -d "Add directory pattern to exclusion list"
+complete -c nvm_auto_use_config -n "not __fish_seen_subcommand_from auto_install silent debounce exclude include manager reset" -a include -d "Remove directory pattern from exclusion list"
+complete -c nvm_auto_use_config -n "not __fish_seen_subcommand_from auto_install silent debounce exclude include manager reset" -a manager -d "Set preferred version manager"
+complete -c nvm_auto_use_config -n "not __fish_seen_subcommand_from auto_install silent debounce exclude include manager reset" -a reset -d "Reset all configuration to defaults"
+
+# Boolean options
+complete -c nvm_auto_use_config -n "__fish_seen_subcommand_from auto_install silent" -a "on enable true 1" -d Enable
+complete -c nvm_auto_use_config -n "__fish_seen_subcommand_from auto_install silent" -a "off disable false 0" -d Disable
+
+# Manager options
+complete -c nvm_auto_use_config -n "__fish_seen_subcommand_from manager" -a nvm -d "Use Node Version Manager"
+complete -c nvm_auto_use_config -n "__fish_seen_subcommand_from manager" -a fnm -d "Use Fast Node Manager"
+complete -c nvm_auto_use_config -n "__fish_seen_subcommand_from manager" -a volta -d "Use Volta"
+complete -c nvm_auto_use_config -n "__fish_seen_subcommand_from manager" -a asdf -d "Use asdf"
+
+# Common directory patterns for exclusion
+complete -c nvm_auto_use_config -n "__fish_seen_subcommand_from exclude" -a node_modules -d "Exclude node_modules directories"
+complete -c nvm_auto_use_config -n "__fish_seen_subcommand_from exclude" -a ".git" -d "Exclude .git directories"
+complete -c nvm_auto_use_config -n "__fish_seen_subcommand_from exclude" -a build -d "Exclude build directories"
+complete -c nvm_auto_use_config -n "__fish_seen_subcommand_from exclude" -a dist -d "Exclude dist directories"
diff --git a/functions/nvm_auto_use.fish b/functions/nvm_auto_use.fish
index d52dc4d..cc61a3f 100644
--- a/functions/nvm_auto_use.fish
+++ b/functions/nvm_auto_use.fish
@@ -1,17 +1,130 @@
 function nvm_auto_use --on-variable PWD
-  set -l nvmrc_file (nvm_find_nvmrc)
-  if test -n "$nvmrc_file"
-    set -l node_version (cat "$nvmrc_file")
-
-    # Check the current version
-    set -l current_version (node -v 2>/dev/null | sed 's/v//')
-
-    if test "$node_version" != "$current_version"
-      if not nvm use $node_version 2>/dev/null
-        echo "Node.js version $node_version not found, installing..."
-        nvm install $node_version && nvm use $node_version
-      end
+    # Detect available Node.js version manager
+    set -l available_managers (nvm_compat_detect 2>/dev/null | tail -n 1)
+    if test -z "$available_managers"
+        return
     end
-  end
-end
 
+    # Use preferred manager or first available
+    set -l manager
+    if test -n "$_nvm_auto_use_preferred_manager"
+        if contains "$_nvm_auto_use_preferred_manager" $available_managers
+            set manager "$_nvm_auto_use_preferred_manager"
+        end
+    end
+
+    if test -z "$manager"
+        set manager $available_managers[1]
+    end
+
+    # Check if project detection is enabled and we're in a Node.js project
+    if set -q _nvm_auto_use_project_only
+        if not nvm_project_detect
+            return
+        end
+    end
+
+    # Export NODE_VERSION environment variable
+    if command -q node
+        set -gx NODE_VERSION (node -v 2>/dev/null | string replace 'v' '')
+    end
+
+    # Check for excluded directories
+    set -l current_dir (pwd)
+    for pattern in $_nvm_auto_use_excluded_dirs node_modules .git
+        if string match -q "*/$pattern" "$current_dir"; or string match -q "*/$pattern/*" "$current_dir"
+            return
+        end
+    end
+
+    # Debouncing: prevent rapid switching
+    set -l debounce_ms (_nvm_auto_use_get_debounce)
+    set -l current_time (date +%s%3N 2>/dev/null; or date +%s)
+    if test -n "$_nvm_auto_use_last_change"
+        set -l time_diff (math "$current_time - $_nvm_auto_use_last_change")
+        if test $time_diff -lt $debounce_ms
+            return
+        end
+    end
+    set -g _nvm_auto_use_last_change $current_time
+
+    set -l nvmrc_file (nvm_find_nvmrc)
+
+    # Cache check: if same file and version, skip processing
+    if test "$nvmrc_file" = "$_nvm_auto_use_cached_file"
+        return
+    end
+
+    if test -n "$nvmrc_file"
+        set -l node_version (nvm_extract_version "$nvmrc_file")
+
+        # Cache the file path
+        set -g _nvm_auto_use_cached_file "$nvmrc_file"
+
+        # Validate node version format (basic semver or major version)
+        if not string match -qr '^v?[0-9]+(\..*)?$' "$node_version"
+            if not set -q _nvm_auto_use_silent
+                echo "Invalid Node.js version format in $nvmrc_file: $node_version" >&2
+            end
+            return 1
+        end
+
+        # Remove 'v' prefix if present
+        set node_version (string replace -r '^v' '' "$node_version")
+
+        # Cache the version
+        set -g _nvm_auto_use_cached_version "$node_version"
+
+        # Check the current version
+        set -l current_version
+        if command -q node
+            set current_version (node -v 2>/dev/null | sed 's/v//')
+        end
+
+        if test "$node_version" != "$current_version"
+            if not set -q _nvm_auto_use_silent
+                echo "Switching to Node.js v$node_version"
+            end
+
+            # Send notification if enabled
+            if not set -q _nvm_auto_use_silent
+                nvm_notify "Switched to Node.js v$node_version"
+            end
+
+            if not nvm_compat_use $manager $node_version 2>/dev/null
+                # Check if auto-install is disabled
+                if set -q _nvm_auto_use_no_install
+                    if not set -q _nvm_auto_use_silent
+                        echo "Node.js version $node_version not found (auto-install disabled)" >&2
+                    end
+                    return 1
+                end
+
+                if not set -q _nvm_auto_use_silent
+                    echo "Node.js version $node_version not found, installing..."
+                end
+                if nvm_compat_install $manager $node_version >/dev/null 2>&1
+                    nvm_compat_use $manager $node_version >/dev/null 2>&1
+                    if not set -q _nvm_auto_use_silent
+                        echo "Installed and switched to Node.js v$node_version"
+                    end
+                else
+                    if not set -q _nvm_auto_use_silent
+                        echo "Failed to install Node.js version $node_version" >&2
+                    end
+                    return 1
+                end
+            end
+
+            # Update cached version after successful switch
+            set -g _nvm_auto_use_cached_version "$node_version"
+
+            # Update NODE_VERSION environment variable
+            set -gx NODE_VERSION "$node_version"
+        end
+    else
+        # Clear cache if no .nvmrc found
+        set -e _nvm_auto_use_cached_file
+        set -e _nvm_auto_use_cached_version
+    end
+end
diff --git a/functions/nvm_auto_use_config.fish b/functions/nvm_auto_use_config.fish
new file mode 100644
index 0000000..f0f88a2
--- /dev/null
+++ b/functions/nvm_auto_use_config.fish
@@ -0,0 +1,100 @@
+function nvm_auto_use_config -d "Configure nvm-auto-use settings"
+    if test (count $argv) -eq 0
+        echo "nvm-auto-use configuration:"
+        echo "  auto_install: "(test -n "$_nvm_auto_use_no_install"; and echo "disabled"; or echo "enabled")
+        echo "  silent: "(test -n "$_nvm_auto_use_silent"; and echo "enabled"; or echo "disabled")
+        echo "  debounce_ms: "(_nvm_auto_use_get_debounce)
+        echo "  excluded_dirs: "(_nvm_auto_use_get_excluded_dirs)
+        echo "  preferred_manager: "(test -n "$_nvm_auto_use_preferred_manager"; and echo "$_nvm_auto_use_preferred_manager"; or echo "auto-detect")
+        return
+    end
+
+    switch $argv[1]
+        case auto_install
+            switch $argv[2]
+                case on enable true 1
+                    set -e _nvm_auto_use_no_install
+                    echo "Auto-install enabled"
+                case off disable false 0
+                    set -g _nvm_auto_use_no_install 1
+                    echo "Auto-install disabled"
+                case '*'
+                    echo "Usage: nvm_auto_use_config auto_install [on|off]"
+            end
+        case silent
+            switch $argv[2]
+                case on enable true 1
+                    set -g _nvm_auto_use_silent 1
+                    echo "Silent mode enabled"
+                case off disable false 0
+                    set -e _nvm_auto_use_silent
+                    echo "Silent mode disabled"
+                case '*'
+                    echo "Usage: nvm_auto_use_config silent [on|off]"
+            end
+        case debounce
+            if test -n "$argv[2]" -a (string match -r '^[0-9]+$' "$argv[2]")
+                set -g _nvm_auto_use_debounce_ms $argv[2]
+                echo "Debounce set to $argv[2]ms"
+            else
+                echo "Usage: nvm_auto_use_config debounce <milliseconds>"
+            end
+        case exclude
+            if test -n "$argv[2]"
+                set -g _nvm_auto_use_excluded_dirs $_nvm_auto_use_excluded_dirs $argv[2]
+                echo "Added $argv[2] to excluded directories"
+            else
+                echo "Usage: nvm_auto_use_config exclude <directory_pattern>"
+            end
+        case include
+            if test -n "$argv[2]"
+                set -l index (contains -i "$argv[2]" $_nvm_auto_use_excluded_dirs)
+                if test -n "$index"
+                    set -e _nvm_auto_use_excluded_dirs[$index]
+                    echo "Removed $argv[2] from excluded directories"
+                else
+                    echo "$argv[2] was not in excluded directories"
+                end
+            else
+                echo "Usage: nvm_auto_use_config include <directory_pattern>"
+            end
+        case manager
+            if test -n "$argv[2]"
+                if contains "$argv[2]" nvm fnm volta asdf
+                    set -g _nvm_auto_use_preferred_manager "$argv[2]"
+                    echo "Preferred manager set to $argv[2]"
+                else
+                    echo "Unsupported manager. Supported: nvm, fnm, volta, asdf"
+                end
+            else
+                set -e _nvm_auto_use_preferred_manager
+                echo "Reset to auto-detect manager"
+            end
+        case reset
+            set -e _nvm_auto_use_no_install
+            set -e _nvm_auto_use_silent
+            set -e _nvm_auto_use_debounce_ms
+            set -e _nvm_auto_use_excluded_dirs
+            set -e _nvm_auto_use_preferred_manager
+            echo "Configuration reset to defaults"
+        case '*'
+            echo "Usage: nvm_auto_use_config [auto_install|silent|debounce|exclude|include|manager|reset] [value]"
+            return 1
+    end
+end
+
+function _nvm_auto_use_get_debounce
+    if test -n "$_nvm_auto_use_debounce_ms"
+        echo "$_nvm_auto_use_debounce_ms"
+    else
+        echo 500
+    end
+end
+
+function _nvm_auto_use_get_excluded_dirs
+    if test -n "$_nvm_auto_use_excluded_dirs"
+        string join ', ' $_nvm_auto_use_excluded_dirs
+    else
+        echo "node_modules, .git"
+    end
+end
diff --git a/functions/nvm_auto_use_silent.fish b/functions/nvm_auto_use_silent.fish
new file mode 100644
index 0000000..fc2cd89
--- /dev/null
+++ b/functions/nvm_auto_use_silent.fish
@@ -0,0 +1,22 @@
+function nvm_auto_use_silent -d "Enable or disable silent mode for nvm-auto-use"
+    if test (count $argv) -eq 0
+        if set -q _nvm_auto_use_silent
+            echo "Silent mode: enabled"
+        else
+            echo "Silent mode: disabled"
+        end
+        return
+    end
+
+    switch $argv[1]
+        case on enable true 1
+            set -g _nvm_auto_use_silent 1
+            echo "Silent mode enabled"
+        case off disable false 0
+            set -e _nvm_auto_use_silent
+            echo "Silent mode disabled"
+        case '*'
+            echo "Usage: nvm_auto_use_silent [on|off]"
+            return 1
+    end
+end
diff --git a/functions/nvm_compat_detect.fish b/functions/nvm_compat_detect.fish
new file mode 100644
index 0000000..4862c63
--- /dev/null
+++ b/functions/nvm_compat_detect.fish
@@ -0,0 +1,71 @@
+function nvm_compat_detect -d "Detect available Node.js version managers"
+    set -l managers
+
+    if command -q nvm
+        set managers $managers nvm
+    end
+
+    if command -q fnm
+        set managers $managers fnm
+    end
+
+    if command -q volta
+        set managers $managers volta
+    end
+
+    if command -q asdf; and test -f ~/.tool-versions
+        if grep -q nodejs ~/.tool-versions 2>/dev/null
+            set managers $managers asdf
+        end
+    end
+
+    if test (count $managers) -eq 0
+        echo "No supported Node.js version managers found"
+        return 1
+    end
+
+    echo "Available managers:" (string join ", " $managers)
+    echo $managers
+end
+
+function nvm_compat_use -a manager version -d "Use specified version with detected manager"
+    if test -z "$manager" -o -z "$version"
+        echo "Usage: nvm_compat_use <manager> <version>"
+        return 1
+    end
+
+    switch $manager
+        case nvm
+            nvm use $version
+        case fnm
+            fnm use $version
+        case volta
+            volta pin node@$version
+        case asdf
+            asdf local nodejs $version
+        case '*'
+            echo "Unsupported manager: $manager"
+            return 1
+    end
+end
+
+function nvm_compat_install -a manager version -d "Install specified version with detected manager"
+    if test -z "$manager" -o -z "$version"
+        echo "Usage: nvm_compat_install <manager> <version>"
+        return 1
+    end
+
+    switch $manager
+        case nvm
+            nvm install $version
+        case fnm
+            fnm install $version
+        case volta
+            volta install node@$version
+        case asdf
+            asdf install nodejs $version
+        case '*'
+            echo "Unsupported manager: $manager"
+            return 1
+    end
+end
diff --git a/functions/nvm_extract_version.fish b/functions/nvm_extract_version.fish
new file mode 100644
index 0000000..7f67391
--- /dev/null
+++ b/functions/nvm_extract_version.fish
@@ -0,0 +1,51 @@
+function nvm_extract_version -a file_path -d "Extract Node.js version from various file formats"
+    if test -z "$file_path"
+        return 1
+    end
+
+    set -l file_name (basename "$file_path")
+    set -l version_info (string split ':' "$file_path")
+    set -l actual_file $version_info[1]
+    set -l format $version_info[2]
+
+    if not test -f "$actual_file" -a -r "$actual_file"
+        return 1
+    end
+
+    switch "$format"
+        case engines.node
+            # Extract from package.json engines.node field
+            if command -q jq
+                set -l version (jq -r '.engines.node // empty' "$actual_file" 2>/dev/null)
+                if test -n "$version" -a "$version" != null
+                    # Handle version ranges - extract first valid version
+                    set version (string replace -r '^[^0-9]*([0-9]+\.?[0-9]*\.?[0-9]*).*' '$1' "$version")
+                    echo "$version"
+                    return 0
+                end
+            end
+        case nodejs
+            # Extract from .tool-versions nodejs line
+            set -l version (grep '^nodejs ' "$actual_file" | cut -d' ' -f2 | string trim)
+            if test -n "$version"
+                echo "$version"
+                return 0
+            end
+        case '*'
+            # Standard .nvmrc or .node-version file
+            set -l version (cat "$actual_file" | string trim)
+            if test -n "$version"
+                # Handle nvm aliases
+                switch "$version"
+                    case 'lts/*' lts latest stable node
+                        if command -q nvm
+                            set version (nvm version-remote "$version" 2>/dev/null | string replace 'v' '')
+                        end
+                end
+                echo "$version"
+                return 0
+            end
+    end
+
+    return 1
+end
diff --git a/functions/nvm_find_nvmrc.fish b/functions/nvm_find_nvmrc.fish
index 2af1b52..2512ca9 100644
--- a/functions/nvm_find_nvmrc.fish
+++ b/functions/nvm_find_nvmrc.fish
@@ -1,11 +1,40 @@
 function nvm_find_nvmrc
-  set -l dir (pwd)
-  while test "$dir" != "/"
-    if test -f "$dir/.nvmrc"
-      echo "$dir/.nvmrc"
-      return
-    end
-    set dir (dirname "$dir")
-  end
-end
+    set -l dir (pwd)
 
+    # Validate current directory
+    if test -z "$dir"
+        return 1
+    end
+
+    while test "$dir" != /
+        # Check for multiple file formats in order of preference
+        for file in .nvmrc .node-version .tool-versions package.json
+            set -l file_path "$dir/$file"
+            if test -f "$file_path" -a -r "$file_path"
+                switch $file
+                    case package.json
+                        # Extract engines.node field from package.json
+                        if command -q jq
+                            set -l node_version (jq -r '.engines.node // empty' "$file_path" 2>/dev/null)
+                            if test -n "$node_version" -a "$node_version" != null
+                                echo "$file_path:engines.node"
+                                return 0
+                            end
+                        end
+                    case .tool-versions
+                        # Check if .tool-versions contains nodejs entry
+                        if grep -q '^nodejs ' "$file_path" 2>/dev/null
+                            echo "$file_path:nodejs"
+                            return 0
+                        end
+                    case '*'
+                        echo "$file_path"
+                        return 0
+                end
+            end
+        end
+        set dir (dirname "$dir")
+    end
+
+    return 1
+end
diff --git a/functions/nvm_notify.fish b/functions/nvm_notify.fish
new file mode 100644
index 0000000..a2615f1
--- /dev/null
+++ b/functions/nvm_notify.fish
@@ -0,0 +1,32 @@
+function nvm_notify -a message -d "Send notification for Node.js version changes"
+    if test -z "$message"
+        return 1
+    end
+
+    # Check if notifications are enabled
+    if set -q _nvm_auto_use_no_notifications
+        return
+    end
+
+    # Try different notification methods
+    if command -q osascript # macOS
+        osascript -e "display notification \"$message\" with title \"nvm-auto-use\""
+    else if command -q notify-send # Linux
+        notify-send nvm-auto-use "$message"
+    else if command -q terminal-notifier # macOS alternative
+        terminal-notifier -title nvm-auto-use -message "$message"
+    end
+end
+
+function nvm_project_detect -d "Check if current directory is a Node.js project"
+    set -l dir (pwd)
+
+    while test "$dir" != /
+        if test -f "$dir/package.json"
+            return 0
+        end
+        set dir (dirname "$dir")
+    end
+
+    return 1
+end
diff --git a/functions/nvm_version_prompt.fish b/functions/nvm_version_prompt.fish
new file mode 100644
index 0000000..7f73e0a
--- /dev/null
+++ b/functions/nvm_version_prompt.fish
@@ -0,0 +1,26 @@
+function nvm_version_prompt -d "Display current Node.js version for prompt integration"
+    if command -q node
+        set -l version (node -v 2>/dev/null | string replace 'v' '')
+        if test -n "$version"
+            echo "⬢ $version"
+        end
+    end
+end
+
+function nvm_version_status -d "Show detailed Node.js version status"
+    if command -q node
+        set -l version (node -v 2>/dev/null)
+        set -l npm_version (npm -v 2>/dev/null)
+
+        echo "Node.js: $version"
+        if test -n "$npm_version"
+            echo "npm: v$npm_version"
+        end
+
+        if set -q _nvm_auto_use_cached_file
+            echo "Auto-use: $_nvm_auto_use_cached_file"
+        end
+    else
+        echo "Node.js: not installed"
+    end
+end