Added doc about supported types

Author: odrobnik

Sources/SwiftMCP/SwiftMCP.docc/Articles/SupportedTypes.md

@@ -0,0 +1,134 @@
+# Supported Types in MCP Tools
+
+Learn about the parameter types and function signatures supported by MCP tools.
+
+## Overview
+
+When creating MCP tools using the `@MCPTool` macro, you can use various parameter types and function signatures. This article covers all supported types and shows examples of how to use them.
+
+## Parameter Types
+
+MCP tools support the following parameter types:
+
+### Basic Types
+- `Int`
+- `Double`
+- `Float`
+- `String`
+- `Bool`
+
+### Array Types
+- `[Int]`
+- `[Double]`
+- `[Float]`
+- `[String]`
+- `[Bool]`
+
+### Enum Types
+Enums without associated values that conform to `CaseIterable` and `Sendable` are supported. By default, the case labels are used as strings when the enum is serialized. You can customize the string representation by implementing `CustomStringConvertible`:
+
+```swift
+// Default behavior uses case labels
+enum SearchOption: CaseIterable, Sendable {
+    case all      // Will be serialized as "all"
+    case unread   // Will be serialized as "unread"
+    case flagged  // Will be serialized as "flagged"
+}
+
+// Custom string representation using CustomStringConvertible
+enum FilterOption: CaseIterable, Sendable, CustomStringConvertible {
+    case newest
+    case oldest
+    case popular
+    
+    var description: String {
+        switch self {
+        case .newest: return "SORT_NEW"
+        case .oldest: return "SORT_OLD"
+        case .popular: return "SORT_POPULAR"
+        }
+    }
+}
+
+// Raw values are ignored for serialization
+enum Priority: String, CaseIterable, Sendable {
+    case high = "H"    // Will be serialized as "high"
+    case medium = "M"  // Will be serialized as "medium"
+    case low = "L"     // Will be serialized as "low"
+}
+```
+
+## Function Signatures
+
+MCP tools support various function signatures:
+
+### Basic Functions
+```swift
+@MCPTool
+func add(a: Int, b: Int) -> Int {
+    return a + b
+}
+```
+
+### Async Functions
+```swift
+@MCPTool
+func fetchData(query: String) async -> String {
+    // ... async implementation
+}
+```
+
+### Throwing Functions
+```swift
+@MCPTool
+func divide(numerator: Double, denominator: Double) throws -> Double {
+    guard denominator != 0 else {
+        throw MathError.divisionByZero
+    }
+    return numerator / denominator
+}
+```
+
+### Async Throwing Functions
+```swift
+@MCPTool
+func processData(input: String) async throws -> String {
+    // ... async throwing implementation
+}
+```
+
+## Return Types
+
+The return type of an MCP tool must conform to both `Sendable` and `Codable`. This includes:
+
+- All basic types (`Int`, `Double`, `Float`, `String`, `Bool`)
+- Arrays of basic types
+- Custom types that conform to both protocols
+- `Void` (for functions that don't return a value)
+
+## Default Values
+
+Parameters can have default values:
+
+```swift
+@MCPTool
+func greet(name: String = "World", times: Int = 1) -> String {
+    return String(repeating: "Hello, \(name)! ", count: times)
+}
+```
+
+## Tips
+
+- For enum parameters, ensure they conform to `CaseIterable` and `Sendable`
+- By default, case labels are used for serialization
+- You can customize enum string representation by implementing `CustomStringConvertible`
+- Raw values are ignored for serialization purposes
+- For custom types, ensure they conform to both `Sendable` and `Codable`
+- Default values are supported for all parameter types
+- Function parameters and return types must be `Sendable` to ensure thread safety
+
+## Topics
+
+### Related Articles
+- ``MCPServer``
+- ``MCPTool`` 

Sources/SwiftMCP/SwiftMCP.docc/SwiftMCP.md

@@ -35,11 +35,12 @@ Start with <doc:GettingStarted> to create your first MCP server, then explore <d
 
 ## Topics
 
-### Essentials
+### Getting Started
 
 - <doc:GettingStarted>
 - <doc:CoreConcepts>
 - <doc:SwiftMCPTutorials>
+- <doc:SupportedTypes>
 
 ### Macros