Flutter Deprecations MCP Server

Flutter Deprecations MCP Server

This MCP server tracks Flutter API deprecations and provides tools to check code for deprecated APIs and suggest replacements.

Project Structure

flutter-deprecations-server/
├── cmd/
│   └── server/          # Main application entry point
│       └── main.go
├── internal/            # Private application code
│   ├── handlers/        # MCP tool handlers
│   │   ├── mcp_handlers.go
│   │   ├── mcp_handlers_test.go
│   │   └── testdata/
│   ├── models/          # Data structures
│   │   └── flutter.go
│   └── services/        # Business logic
│       ├── cache.go
│       ├── cache_test.go
│       ├── deprecations.go
│       ├── deprecations_test.go
│       ├── flutter_api.go
│       ├── flutter_api_test.go
│       ├── flutter_version.go
│       ├── interfaces.go
│       ├── version_info.go
│       ├── version_info_test.go
│       └── testdata/
├── pkg/                 # Public libraries
│   └── config/          # Configuration constants
│       └── config.go
├── bin/                 # Compiled binaries
├── Makefile            # Build automation
├── go.mod              # Go module definition
├── go.sum              # Dependency checksums
└── README.md

Features

• Source-based deprecation tracking: Directly scans Flutter's GitHub source code for @Deprecated annotations
• Local caching: Stores deprecations locally with 24-hour cache duration
• Code analysis: Analyzes Flutter code snippets for deprecated APIs
• Replacement suggestions: Provides modern alternatives for deprecated APIs
• Comprehensive scanning: Scans key Flutter directories (widgets, material, cupertino, services, etc.)
• Version checking: Gets latest Flutter version using Flutter CLI (most reliable) with GitHub API fallback
• Multi-platform support: Checks FVM and Docker image availability
• Command-line cache management: Manual cache updates and clearing with progress reporting
• Short command options: Support for both long and short command flags
• Rate limit handling: Graceful handling of GitHub API rate limits with helpful error messages
• Verbose logging: Detailed logging with -vvv flag for troubleshooting

MCP Tools

1. check_flutter_deprecations

Analyzes provided Flutter code for deprecated APIs and suggests replacements.

Parameters:

• code (string): Flutter code snippet to analyze

Example:

Color.red.withOpacity(0.5)  // Will suggest Color.red.withValues(alpha: 0.5)

2. list_flutter_deprecations

Lists all known Flutter deprecations from the cache.

Parameters: None

Returns: Complete list of deprecations with replacements and version information.

3. check_flutter_version_info

Gets the latest stable Flutter version and checks availability across different tools and platforms.

Parameters: None

Returns:

• Latest stable Flutter version (using Flutter CLI when available, GitHub API fallback)
• Flutter CLI installation status and channel information
• FVM installation status and version availability
• Docker image availability for instrumentisto/flutter and ghcr.io/cirruslabs/flutter
• Usage examples and installation commands

Known Deprecations

The server includes built-in patterns for common deprecations:

• Color.withOpacity() → Color.withValues(alpha:)
• RaisedButton → ElevatedButton
• FlatButton → TextButton
• OutlineButton → OutlinedButton
• Scaffold.of(context).showSnackBar → ScaffoldMessenger.of(context).showSnackBar

Installation

Using Makefile (Recommended)

# Install dependencies
make deps

# Build the server
make build

# Run the server
make run

# Build for multiple platforms
make build-all

Manual Build

# Install dependencies
go mod tidy

# Build the server
go build -o bin/flutter-deprecations-server ./cmd/server

# Run the server
./bin/flutter-deprecations-server

# Update deprecations cache manually
./bin/flutter-deprecations-server --update

# Update with verbose logging  
./bin/flutter-deprecations-server --update -vvv

# Clear deprecations cache
./bin/flutter-deprecations-server --clear-cache

# Show current cache contents
./bin/flutter-deprecations-server --show-cache

# Show help information
./bin/flutter-deprecations-server --help

Development

# Format code
make fmt

# Vet code
make vet

# Run tests
make test

# Development build and run
make dev

Configuration with AI Assistants

Add to your MCP configuration (e.g., mcp.json):

{
  "mcpServers": {
    "flutter-deprecations": {
      "command": "/path/to/flutter-deprecations-server/bin/flutter-deprecations-server",
      "args": [],
      "env": {}
    }
  }
}

Version Detection

The server uses a reliable multi-tier approach to detect the latest Flutter version:

1. Primary: Flutter CLI (flutter --version) - Most accurate, matches developer environment
2. Official API: Google Storage Flutter releases API (https://storage.googleapis.com/flutter_infra_release/releases/releases_linux.json) - Faster and more reliable than GitHub
3. Fallback: GitHub API releases - Used when both Flutter CLI and official API are unavailable
4. Channel Detection: Identifies stable/beta/dev channels from official sources
5. Docker Registry Support: Checks both Docker Hub and GitHub Container Registry

Cache Location

Deprecations are cached at: ~/.flutter-deprecations/flutter_deprecations.json

The cache is automatically updated every 24 hours when tools are used.

Usage Examples

Ask your AI assistant:

• "Check this Flutter code for deprecations: Color.red.withOpacity(0.5)"
• "List all Flutter deprecations"
• "What should I use instead of RaisedButton?"
• "What's the latest Flutter version and is it available in FVM and Docker?"
• "Check Flutter version info"

Command Line Usage

The server supports several command-line options for cache management:

# Show help and available options
./bin/flutter-deprecations-server --help
./bin/flutter-deprecations-server -h        # Short version

# Update deprecations cache with progress reporting
./bin/flutter-deprecations-server --update
./bin/flutter-deprecations-server -u        # Short version

# Update with verbose logging for troubleshooting
./bin/flutter-deprecations-server --update -vvv
./bin/flutter-deprecations-server -u -vvv   # Short version

# Clear deprecations cache
./bin/flutter-deprecations-server --clear-cache
./bin/flutter-deprecations-server -cc       # Short version

# Show current cache contents
./bin/flutter-deprecations-server --show-cache
./bin/flutter-deprecations-server -sc       # Short version

# Start the MCP server (default behavior)
./bin/flutter-deprecations-server

Available Options

• --help, -h: Show help information with usage examples
• --update, -u: Update the Flutter deprecations cache and exit
• --clear-cache, -cc: Clear the Flutter deprecations cache and exit
• --show-cache, -sc: Display the current Flutter deprecations cache and exit
• --vvv: Enable verbose logging for detailed troubleshooting

Architecture

The project follows Go best practices with a clean architecture:

• cmd/: Application entry points
• internal/: Private application code (cannot be imported by other projects)
• pkg/: Public libraries that can be imported
• Makefile: Build automation and common tasks

Services Layer

• CacheService: Handles local file caching with clear functionality
• FlutterAPIService: Manages GitHub API interactions with rate limit handling, source code scanning, and Docker registry checks
• FlutterVersionService: Gets Flutter version directly from Flutter CLI
• DeprecationService: Analyzes and manages deprecation data from Flutter source code
• VersionInfoService: Provides comprehensive version and availability information

Handlers Layer

• MCPHandlers: Implements MCP tool interfaces and coordinates service calls

Testing

• Comprehensive test suite: Unit tests for all services and handlers
• Mock services: Test infrastructure with dependency injection
• Test coverage: Run make test-coverage to generate coverage reports