feat: Add ChatAnthropic integration (#477)

docs/_sidebar.md

@@ -56,6 +56,7 @@
           - [Tool calling](/modules/model_io/models/chat_models/how_to/tools.md)
           - [LLMChain](/modules/model_io/models/chat_models/how_to/llm_chain.md)
         - Integrations
+          - [Anthropic](/modules/model_io/models/chat_models/integrations/anthropic.md) 
           - [OpenAI](/modules/model_io/models/chat_models/integrations/openai.md)
           - [Firebase Vertex AI](/modules/model_io/models/chat_models/integrations/firebase_vertex_ai.md)
           - [GCP Vertex AI](/modules/model_io/models/chat_models/integrations/gcp_vertex_ai.md)

docs/modules/model_io/models/chat_models/how_to/tools.md

@@ -3,6 +3,7 @@
 > We use the term "tool calling" interchangeably with "function calling". Although function calling is sometimes meant to refer to invocations of a single function, we treat all models as though they can return multiple tool or function calls in each message.
 
 > Tool calling is currently supported by:
+> - [`ChatAnthropic`](/modules/model_io/models/chat_models/integrations/anthropic.md)
 > - [`ChatOpenAI`](/modules/model_io/models/chat_models/integrations/openai.md)
 > - [`ChatFirebaseVertexAI`](/modules/model_io/models/chat_models/integrations/firebase_vertex_ai.md)
 > - [`ChatGoogleGenerativeAI`](/modules/model_io/models/chat_models/integrations/googleai.md)

docs/modules/model_io/models/chat_models/integrations/anthropic.md

@@ -0,0 +1,145 @@
+# ChatAnthropic
+
+Wrapper around [Anthropic Messages API](https://docs.anthropic.com/en/api/messages) (aka Claude API).
+
+## Setup
+
+The Anthropic API uses API keys for authentication. Visit your [API Keys](https://console.anthropic.com/settings/keys) page to retrieve the API key you'll use in your requests.
+
+The following models are available:
+- `claude-3-5-sonnet-20240620`
+- `claude-3-haiku-20240307`
+- `claude-3-opus-20240229`
+- `claude-3-sonnet-20240229`
+- `claude-2.0`
+- `claude-2.1`
+
+Mind that the list may not be up-to-date. See https://docs.anthropic.com/en/docs/about-claude/models for the updated list.
+
+## Usage
+
+```dart
+final apiKey = Platform.environment['ANTHROPIC_API_KEY'];
+
+final chatModel = ChatAnthropic(
+  apiKey: apiKey,
+  defaultOptions: ChatAnthropicOptions(
+    model: 'claude-3-5-sonnet-20240620',
+    temperature: 0,
+  ),
+);
+
+final chatPrompt = ChatPromptTemplate.fromTemplates([
+  (ChatMessageType.system, 'You are a helpful assistant that translates {input_language} to {output_language}.'),
+  (ChatMessageType.human, 'Text to translate:\n{text}'),
+]);
+
+final chain = chatPrompt | chatModel | StringOutputParser();
+
+final res = await chain.invoke({
+  'input_language': 'English',
+  'output_language': 'French',
+  'text': 'I love programming.',
+});
+print(res);
+// -> 'J'adore programmer.'
+```
+
+## Multimodal support
+
+```dart
+final apiKey = Platform.environment['ANTHROPIC_API_KEY'];
+
+final chatModel = ChatAnthropic(
+  apiKey: apiKey,
+  defaultOptions: ChatAnthropicOptions(
+    model: 'claude-3-5-sonnet-20240620',
+    temperature: 0,
+  ),
+);
+
+final res = await chatModel.invoke(
+  PromptValue.chat([
+    ChatMessage.human(
+      ChatMessageContent.multiModal([
+        ChatMessageContent.text('What fruit is this?'),
+        ChatMessageContent.image(
+          mimeType: 'image/jpeg',
+          data: base64.encode(
+            await File('./bin/assets/apple.jpeg').readAsBytes(),
+          ),
+        ),
+      ]),
+    ),
+  ]),
+);
+
+print(res.output.content);
+// -> 'The fruit in the image is an apple.'
+```
+
+## Streaming
+
+```dart
+final apiKey = Platform.environment['ANTHROPIC_API_KEY'];
+
+final promptTemplate = ChatPromptTemplate.fromTemplates([
+  (ChatMessageType.system, 'You are a helpful assistant that replies only with numbers in order without any spaces or commas.'),
+  (ChatMessageType.human, 'List the numbers from 1 to {max_num}'),
+]);
+
+final chatModel = ChatAnthropic(
+  apiKey: apiKey,
+  defaultOptions: ChatAnthropicOptions(
+    model: 'claude-3-5-sonnet-20240620',
+    temperature: 0,
+  ),
+);
+
+final chain = promptTemplate.pipe(chatModel).pipe(const StringOutputParser());
+
+final stream = chain.stream({'max_num': '30'});
+await stream.forEach(print);
+// 123
+// 456789101
+// 112131415161
+// 718192021222
+// 324252627282
+// 930
+```
+
+## Tool calling
+
+`ChatAnthropic` supports tool calling.
+
+Check the [docs](https://langchaindart.dev/#/modules/model_io/models/chat_models/how_to/tools) for more information on how to use tools.
+
+Example:
+```dart
+const tool = ToolSpec(
+  name: 'get_current_weather',
+  description: 'Get the current weather in a given location',
+  inputJsonSchema: {
+    'type': 'object',
+    'properties': {
+      'location': {
+        'type': 'string',
+        'description': 'The city and state, e.g. San Francisco, CA',
+      },
+    },
+    'required': ['location'],
+  },
+);
+final chatModel = ChatAnthropic(
+  apiKey: apiKey,
+  defaultOptions: ChatAnthropicOptions(
+    model: 'claude-3-5-sonnet-20240620',
+    temperature: 0,
+    tools: [tool],
+  ),
+);
+
+final res = await model.invoke(
+  PromptValue.string('What’s the weather like in Boston and Madrid right now in celsius?'),
+);
+```

examples/docs_examples/bin/modules/model_io/models/chat_models/integrations/anthropic.dart

@@ -0,0 +1,109 @@
+// ignore_for_file: avoid_print
+import 'dart:convert';
+import 'dart:io';
+
+import 'package:langchain/langchain.dart';
+import 'package:langchain_anthropic/langchain_anthropic.dart';
+
+void main(final List<String> arguments) async {
+  await _invokeModel();
+  await _multiModal();
+  await _streaming();
+}
+
+Future<void> _invokeModel() async {
+  final apiKey = Platform.environment['ANTHROPIC_API_KEY'];
+
+  final chatModel = ChatAnthropic(
+    apiKey: apiKey,
+    defaultOptions: const ChatAnthropicOptions(
+      model: 'claude-3-5-sonnet-20240620',
+      temperature: 0,
+    ),
+  );
+
+  final chatPrompt = ChatPromptTemplate.fromTemplates(const [
+    (
+      ChatMessageType.system,
+      'You are a helpful assistant that translates {input_language} to {output_language}.'
+    ),
+    (ChatMessageType.human, 'Text to translate:\n{text}'),
+  ]);
+
+  final chain = chatPrompt | chatModel | const StringOutputParser();
+
+  final res = await chain.invoke({
+    'input_language': 'English',
+    'output_language': 'French',
+    'text': 'I love programming.',
+  });
+  print(res);
+  // -> 'J'adore programmer.'
+
+  chatModel.close();
+}
+
+Future<void> _multiModal() async {
+  final apiKey = Platform.environment['ANTHROPIC_API_KEY'];
+
+  final chatModel = ChatAnthropic(
+    apiKey: apiKey,
+    defaultOptions: const ChatAnthropicOptions(
+      model: 'claude-3-5-sonnet-20240620',
+      temperature: 0,
+    ),
+  );
+  final res = await chatModel.invoke(
+    PromptValue.chat([
+      ChatMessage.human(
+        ChatMessageContent.multiModal([
+          ChatMessageContent.text('What fruit is this?'),
+          ChatMessageContent.image(
+            mimeType: 'image/jpeg',
+            data: base64.encode(
+              await File('./bin/assets/apple.jpeg').readAsBytes(),
+            ),
+          ),
+        ]),
+      ),
+    ]),
+  );
+  print(res.output.content);
+  // -> 'The fruit in the image is an apple.'
+
+  chatModel.close();
+}
+
+Future<void> _streaming() async {
+  final apiKey = Platform.environment['ANTHROPIC_API_KEY'];
+
+  final promptTemplate = ChatPromptTemplate.fromTemplates(const [
+    (
+      ChatMessageType.system,
+      'You are a helpful assistant that replies only with numbers '
+          'in order without any spaces or commas.',
+    ),
+    (ChatMessageType.human, 'List the numbers from 1 to {max_num}'),
+  ]);
+
+  final chatModel = ChatAnthropic(
+    apiKey: apiKey,
+    defaultOptions: const ChatAnthropicOptions(
+      model: 'claude-3-5-sonnet-20240620',
+      temperature: 0,
+    ),
+  );
+
+  final chain = promptTemplate.pipe(chatModel).pipe(const StringOutputParser());
+
+  final stream = chain.stream({'max_num': '30'});
+  await stream.forEach(print);
+  // 123
+  // 456789101
+  // 112131415161
+  // 718192021222
+  // 324252627282
+  // 930
+
+  chatModel.close();
+}

examples/docs_examples/pubspec.lock

@@ -9,6 +9,13 @@ packages:
       url: "https://pub.dev"
     source: hosted
     version: "1.0.6"
+  anthropic_sdk_dart:
+    dependency: "direct overridden"
+    description:
+      path: "../../packages/anthropic_sdk_dart"
+      relative: true
+    source: path
+    version: "0.0.1"
   args:
     dependency: transitive
     description:
@@ -239,6 +246,13 @@ packages:
       relative: true
     source: path
     version: "0.7.2"
+  langchain_anthropic:
+    dependency: "direct main"
+    description:
+      path: "../../packages/langchain_anthropic"
+      relative: true
+    source: path
+    version: "0.0.1-dev.1"
   langchain_chroma:
     dependency: "direct main"
     description:

examples/docs_examples/pubspec.yaml

@@ -8,6 +8,7 @@ environment:
 
 dependencies:
   langchain: ^0.7.2
+  langchain_anthropic: ^0.0.1-dev.1
   langchain_chroma: ^0.2.0+5
   langchain_community: 0.2.1+1
   langchain_google: ^0.5.1

examples/docs_examples/pubspec_overrides.yaml

@@ -1,9 +1,13 @@
-# melos_managed_dependency_overrides: chromadb,langchain,langchain_chroma,langchain_google,langchain_mistralai,langchain_ollama,langchain_openai,mistralai_dart,ollama_dart,openai_dart,vertex_ai,langchain_core,langchain_community,tavily_dart
+# melos_managed_dependency_overrides: chromadb,langchain,langchain_chroma,langchain_google,langchain_mistralai,langchain_ollama,langchain_openai,mistralai_dart,ollama_dart,openai_dart,vertex_ai,langchain_core,langchain_community,tavily_dart,anthropic_sdk_dart,langchain_anthropic
 dependency_overrides:
+  anthropic_sdk_dart:
+    path: ../../packages/anthropic_sdk_dart
   chromadb:
     path: ../../packages/chromadb
   langchain:
     path: ../../packages/langchain
+  langchain_anthropic:
+    path: ../../packages/langchain_anthropic
   langchain_chroma:
     path: ../../packages/langchain_chroma
   langchain_community:

packages/anthropic_sdk_dart/README.md

@@ -23,6 +23,7 @@ Unofficial Dart client for [Anthropic](https://docs.anthropic.com/en/api) API (a
 - [Usage](#usage)
   * [Authentication](#authentication)
   * [Messages](#messages)
+  * [Tool use](#tool-use)
 - [Advance Usage](#advance-usage)
   * [Default HTTP client](#default-http-client)
   * [Custom HTTP client](#custom-http-client)

packages/langchain_anthropic/example/langchain_anthropic_example.dart

@@ -1,3 +1,41 @@
-void main() {
-  // TODO
+// ignore_for_file: avoid_print, unused_element
+import 'dart:io';
+
+import 'package:langchain_anthropic/langchain_anthropic.dart';
+import 'package:langchain_core/chat_models.dart';
+import 'package:langchain_core/prompts.dart';
+
+/// Check the docs for more examples:
+/// https://langchaindart.dev
+void main() async {
+  // Uncomment the example you want to run:
+  await _example1();
+  // await _example2();
+}
+
+/// The most basic example of LangChain is calling a model on some input
+Future<void> _example1() async {
+  final openAiApiKey = Platform.environment['ANTHROPIC_API_KEY'];
+  final llm = ChatAnthropic(
+    apiKey: openAiApiKey,
+    defaultOptions: const ChatAnthropicOptions(temperature: 1),
+  );
+  final ChatResult res = await llm.invoke(
+    PromptValue.string('Tell me a joke'),
+  );
+  print(res);
+}
+
+/// Instead of waiting for the full response from the model, you can stream it
+/// while it's being generated
+Future<void> _example2() async {
+  final openAiApiKey = Platform.environment['ANTHROPIC_API_KEY'];
+  final llm = ChatAnthropic(
+    apiKey: openAiApiKey,
+    defaultOptions: const ChatAnthropicOptions(temperature: 1),
+  );
+  final Stream<ChatResult> stream = llm.stream(
+    PromptValue.string('Tell me a joke'),
+  );
+  await stream.forEach((final chunk) => stdout.write(chunk.output.content));
 }

packages/langchain_anthropic/lib/langchain_anthropic.dart

@@ -1,2 +1,4 @@
 /// Anthropic module for LangChain.dart.
 library;
+
+export 'src/chat_models/chat_models.dart';