docs: Update README to reflect XcodeBuildToolPlugin introduction.

Author: fummicc1

README.md

@@ -5,10 +5,14 @@ A command-line tool to analyze Swift code complexity and quality metrics using s
 ## Features
 
 - **Multiple Complexity Metrics**: Supports cyclomatic and cognitive complexity analysis
+- **Xcode Integration**: Seamless integration with Xcode via Build Tool Plugin for complexity feedback during build phase.
+- **Xcode Diagnostics**: Display complexity warnings and errors directly in Xcode editor with accurate line numbers
+- **Configurable Thresholds**: Set custom complexity thresholds via Xcode Build Settings or environment variables
 - **Exit Code Integration**: Returns exit code 1 when complexity thresholds are exceeded, perfect for CI/CD pipelines
-- **Multiple Output Formats**: Text, JSON, and XML output for different use cases
+- **Multiple Output Formats**: Text, JSON, XML, and Xcode diagnostics output for different use cases
 - **Flexible Analysis**: Single files, directories, or recursive directory analysis
 - **Swift Syntax Based**: Uses `swift-syntax` for accurate Swift code parsing
+- **Single Package Dependency**: Both CLI tool and Xcode plugin available from one package
 - **Extensible Architecture**: Designed to support additional quality metrics in the future
 
 ## Quick Start
@@ -25,25 +29,29 @@ swift build -c release
 
 ```bash
 # Analyze a single file
-swift run swift-complexity path/to/file.swift
+swift run SwiftComplexityCLI path/to/file.swift
 
 # Analyze a directory with threshold enforcement
-swift run swift-complexity Sources --threshold 10
+swift run SwiftComplexityCLI Sources --threshold 10
 
 # JSON output for tooling integration
-swift run swift-complexity Sources --format json --recursive
+swift run SwiftComplexityCLI Sources --format json --recursive
+
+# Xcode diagnostics format (for IDE integration)
+swift run SwiftComplexityCLI Sources --format xcode --threshold 15
 ```
 
 ## CLI Integration
 
 The tool returns exit code 1 when any function exceeds the specified complexity threshold, making it ideal for:
+
 - **CI/CD Pipelines**: Fail builds when complexity thresholds are exceeded
 - **Git Hooks**: Prevent commits with overly complex code
 - **Code Quality Gates**: Enforce complexity standards across teams
 
 ```bash
 # Example: Fail if any function has complexity > 15
-swift run swift-complexity Sources --threshold 15 --recursive
+swift run SwiftComplexityCLI Sources --threshold 15 --recursive
 # Exit code 0: All functions below threshold
 # Exit code 1: One or more functions exceed threshold
 ```
@@ -64,35 +72,33 @@ swift run swift-complexity Sources --threshold 15 --recursive
 
 ## Package Structure
 
-This project uses a multi-target architecture:
+Unified package with three targets:
 
-- **SwiftComplexityCore**: Core analysis library (reusable)
+- **SwiftComplexityCore**: Core analysis library
 - **SwiftComplexityCLI**: Command-line interface
-- **SwiftComplexityPlugin**: Xcode Build Tool Plugin for automatic analysis
+- **SwiftComplexityPlugin**: Xcode Build Tool Plugin
 
 ## Usage Examples
 
 ```bash
 # Analyze with verbose output
-swift run swift-complexity Sources --verbose --recursive
+swift run SwiftComplexityCLI Sources --verbose --recursive
 
-# Exclude test files with pattern matching
-swift run swift-complexity Sources --recursive --exclude "*Test*.swift"
+# Exclude test files with pattern matching  
+swift run SwiftComplexityCLI Sources --recursive --exclude "*Test*.swift"
 
 # Show only cognitive complexity above threshold
-swift run swift-complexity Sources --cognitive-only --threshold 5
+swift run SwiftComplexityCLI Sources --cognitive-only --threshold 5
 ```
 
 ## Xcode Build Tool Plugin
 
-swift-complexity can be integrated into your Xcode build process as a Build Tool Plugin:
-
-### Package.swift Integration
+Integrates with both Swift Package Manager and Xcode projects for automatic complexity analysis during builds.
 
-Add swift-complexity as a dependency and apply the plugin to your targets:
+### Swift Package Manager Integration
 
 ```swift
-// swift-tools-version: 5.9
+// swift-tools-version: 6.1
 import PackageDescription
 
 let package = Package(
@@ -103,7 +109,6 @@ let package = Package(
     targets: [
         .target(
             name: "YourTarget",
-            dependencies: [],
             plugins: [
                 .plugin(name: "SwiftComplexityPlugin", package: "swift-complexity")
             ]
@@ -112,23 +117,35 @@ let package = Package(
 )
 ```
 
+### Xcode Project Integration
+
+1. Add swift-complexity package to your Xcode project
+2. In Build Phases, add "SwiftComplexityPlugin" to Run Build Tool Plug-ins
+3. Configure threshold in Build Settings (optional)
+
 ### Configuration
 
-The plugin supports environment-based configuration:
+**Xcode Build Settings:**
 
-- `SWIFT_COMPLEXITY_THRESHOLD`: Set complexity threshold (default: 10)
+- Key: `SWIFT_COMPLEXITY_THRESHOLD`
+- Value: `15` (or any number, defaults to 10)
 
-### Automatic Analysis
+**Environment Variable (SPM):**
 
-Once configured, the plugin will:
-- Run automatically during builds
-- Analyze all Swift files in your target
-- Generate JSON complexity reports
-- Fail the build if complexity thresholds are exceeded
+- `SWIFT_COMPLEXITY_THRESHOLD=15`
 
-## Output Example
+### Features
 
-```
+- **Real-time feedback**: Complexity warnings appear directly in Xcode editor
+- **Accurate positioning**: Errors show at exact function locations  
+- **Build integration**: Builds fail when thresholds are exceeded
+- **Configurable per target**: Different thresholds for different modules
+
+## Output Examples
+
+### CLI Text Output
+
+```text
 File: Sources/ComplexityAnalyzer.swift
 +------------------+----------+----------+
 | Function/Method  | Cyclo.   | Cogn.    |
@@ -140,11 +157,18 @@ File: Sources/ComplexityAnalyzer.swift
 Total: 2 functions, Average Cyclomatic: 4.0, Average Cognitive: 4.5
 ```
 
+### Xcode Diagnostics Output
+
+```text
+/path/to/Sources/MyFile.swift:45:1: error: Function 'complexFunction' has high complexity (Cyclomatic: 15, Cognitive: 23, Threshold: 10)
+/path/to/Sources/MyFile.swift:89:1: warning: Function 'anotherFunction' has high complexity (Cyclomatic: 12, Cognitive: 18, Threshold: 10)
+```
+
 ## Requirements
 
 - Swift 6.1+
 - macOS 14+ or Linux (Ubuntu 22.04+)
 
 ## License
 
-MIT License
+MIT License