Microsoft.Extensions.AI Integration

Cross-SDK comparison

See the centralized MEAI documentation for feature matrices and comparisons across all tryAGI SDKs.

The DeepL SDK provides AIFunction tool wrappers compatible with Microsoft.Extensions.AI. These tools can be used with any IChatClient to give AI models translation, text improvement, and document translation capabilities.

Installation

dotnet add package DeepL

Translation Tool

Use AsTranslateTool() to create an AIFunction that wraps DeepL text translation. Pass it to any IChatClient via ChatOptions.Tools.

using Microsoft.Extensions.AI;
using DeepL;

// Create the DeepL translation tool
var deepLClient = new DeepLClient(
    apiKey: Environment.GetEnvironmentVariable("DEEPL_API_KEY")!);

AIFunction translateTool = deepLClient.AsTranslateTool(
    defaultTargetLanguage: TargetLanguage.En,
    formality: Formality.More);  // Optional: formal tone

// Use with any IChatClient (OpenAI, Anthropic, Ollama, etc.)
IChatClient chatClient = /* your chat client */;

var options = new ChatOptions
{
    Tools = [translateTool],
};

var messages = new List<ChatMessage>
{
    new(ChatRole.User, "Translate 'Bonjour le monde' to German"),
};

while (true)
{
    var response = await chatClient.GetResponseAsync(messages, options);
    messages.AddRange(response.ToChatMessages());

    if (response.FinishReason == ChatFinishReason.ToolCalls)
    {
        var results = await response.CallToolsAsync(options);
        messages.AddRange(results);
        continue;
    }

    Console.WriteLine(response.Text);
    break;
}

Rephrase Tool

Use AsRephraseTool() to create an AIFunction that wraps DeepL's Write API for text improvement.

using Microsoft.Extensions.AI;
using DeepL;

var deepLClient = new DeepLClient(
    apiKey: Environment.GetEnvironmentVariable("DEEPL_API_KEY")!);

AIFunction rephraseTool = deepLClient.AsRephraseTool(
    writingStyle: WritingStyle.Business,  // Optional: business style
    tone: WritingTone.Confident);         // Optional: confident tone

// Use with any IChatClient
IChatClient chatClient = /* your chat client */;

var options = new ChatOptions
{
    Tools = [rephraseTool],
};

var response = await chatClient.GetResponseAsync(
    "Please improve this text: 'The thing is very good and I like it a lot because its nice.'",
    options);

Console.WriteLine(response.Text);

Document Translation Tool

Use AsTranslateDocumentTool() to create an AIFunction that handles the full document translation workflow (upload, poll, download). Supports DOCX, PPTX, XLSX, PDF, HTML, TXT, and more.

using Microsoft.Extensions.AI;
using DeepL;

var deepLClient = new DeepLClient(
    apiKey: Environment.GetEnvironmentVariable("DEEPL_API_KEY")!);

AIFunction docTool = deepLClient.AsTranslateDocumentTool(
    defaultTargetLanguage: TargetLanguage.Fr);

// Use with any IChatClient
IChatClient chatClient = /* your chat client */;

var options = new ChatOptions
{
    Tools = [docTool],
};

Note

The document translation tool accepts base64-encoded file content and returns the translated document as base64. This is best suited for agents that handle file I/O.

Combining All Tools

You can provide all three tools simultaneously, letting the model decide which to use.

using Microsoft.Extensions.AI;
using DeepL;

var deepLClient = new DeepLClient(
    apiKey: Environment.GetEnvironmentVariable("DEEPL_API_KEY")!);

var options = new ChatOptions
{
    Tools =
    [
        deepLClient.AsTranslateTool(),
        deepLClient.AsRephraseTool(),
        deepLClient.AsTranslateDocumentTool(),
    ],
};

IChatClient chatClient = /* your chat client */;

var messages = new List<ChatMessage>
{
    new(ChatRole.User,
        "First improve the grammar of 'Me want go store tomorrow' then translate the improved version to French."),
};

while (true)
{
    var response = await chatClient.GetResponseAsync(messages, options);
    messages.AddRange(response.ToChatMessages());

    if (response.FinishReason == ChatFinishReason.ToolCalls)
    {
        var results = await response.CallToolsAsync(options);
        messages.AddRange(results);
        continue;
    }

    Console.WriteLine(response.Text);
    break;
}

Tool Details

Method	Tool Name	Description
AsTranslateTool()	TranslateText	Translates text between 30+ languages with automatic source detection
AsRephraseTool()	RephraseText	Improves text clarity, tone, and style using DeepL Write API
AsTranslateDocumentTool()	TranslateDocument	Translates documents (DOCX, PDF, TXT, etc.) with automatic polling

AsTranslateTool Parameters

Parameter	Type	Default	Description
defaultTargetLanguage	TargetLanguage	En	Default target language when the model doesn't specify one
formality	Formality?	null	Formality level: Default, Less, More, PreferLess, PreferMore

AsRephraseTool Parameters

Parameter	Type	Default	Description
writingStyle	WritingStyle?	null	Style: Academic, Business, Casual, Simple, or Default
tone	WritingTone?	null	Tone: Confident, Diplomatic, Enthusiastic, Friendly, or Default

AsTranslateDocumentTool Parameters

Parameter	Type	Default	Description
defaultTargetLanguage	TargetLanguage	En	Default target language when the model doesn't specify one
formality	Formality?	null	Formality level for the translation
pollIntervalMs	int	1000	Polling interval in milliseconds when waiting for translation

Language Codes

The translation tools accept standard language codes as strings:

Code	Language	Code	Language
DE	German	FR	French
ES	Spanish	IT	Italian
PT-BR	Portuguese (Brazil)	PT-PT	Portuguese (Portugal)
EN-US	English (US)	EN-GB	English (UK)
JA	Japanese	ZH-HANS	Chinese (Simplified)
KO	Korean	RU	Russian

See the DeepL documentation for the full list of 30+ supported languages.