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# DynamicInstructions

A type that represents dynamic instructions.

```
protocol DynamicInstructions
```

## Overview

Dynamic instructions provide a declarative approach to assembling instructions
and tools that a [`LanguageModelSession`](/documentation/FoundationModels/LanguageModelSession) uses. The framework evaluates them
before every request to the model, so the body can contain conditional logic
that’s based on current app state.

```swift
struct PresentationInstructions: DynamicInstructions {
    // The data source for conditional instructions.
    var isEditingImage = true

    var body: some DynamicInstructions {
        // The instructions and tools that remain the same across any use of this type.
        Instructions {
            "Help people improve their presentation."
        }
        ListPhotosTool()
        AddPhotoTool()

        // Depending on the state of the app, include additional instructions
        // that provide the model with more task-specific instructions and tools.
        if isEditingImage {
            ImageEditingInstructions()
        }
    }
}
```

## Topics

### Implementing dynamic instructions

[`body`](/documentation/FoundationModels/DynamicInstructions/body-swift.property)

The content of the dynamic instructions.

[`Body`](/documentation/FoundationModels/DynamicInstructions/Body-swift.associatedtype)

The type of dynamic instructions that represent these instructions.

[`DynamicInstructions.ForEach`](/documentation/FoundationModels/DynamicInstructions/ForEach)

[`DynamicInstructions.SessionProperty`](/documentation/FoundationModels/DynamicInstructions/SessionProperty)

### Building dynamic instructions

[`DynamicInstructionsBuilder`](/documentation/FoundationModels/DynamicInstructionsBuilder)

[`EmptyDynamicInstructions`](/documentation/FoundationModels/EmptyDynamicInstructions)

An empty dynamic instructions type.

[`ConditionalDynamicInstructions`](/documentation/FoundationModels/ConditionalDynamicInstructions)

A dynamic instructions type that conditionally selects between two conditions.

[`AnyDynamicInstructions`](/documentation/FoundationModels/AnyDynamicInstructions)

A dynamic instructions type that’s type-erased.

[`TupleDynamicInstructions`](/documentation/FoundationModels/TupleDynamicInstructions)

A dynamic instructions type that represents a tuple.


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