Installation & Quickstart

Relevant source files

The following files were used as context for generating this wiki page:

• README.md
• CONTRIBUTING.md
• examples/message/main.go
• usage_test.go
• examples/bedrock/main.go
• examples/vertex/main.go

The Anthropic SDK for Go enables developers to integrate Claude's generative AI capabilities into Go applications. It provides a structured interface for interacting with the Anthropic API, as well as support for cloud-provider specific implementations like AWS Bedrock and Google Vertex AI.

This guide covers the necessary steps to install the library, configure the client, and execute a basic message request.

Sources: README.md:1-12, examples/message/main.go:1-25

Installation

Requirements

The SDK requires Go version 1.22 or higher.

Sources: README.md:46

Adding the Dependency

You can add the SDK to your project using the standard go get command. It is recommended to pin to a specific version for stability.

go get -u 'github.com/anthropics/anthropic-sdk-go@v1.30.0'

Alternatively, you can include the import path in your source code, and Go will manage the dependency during the next build or tidy operation.

import (
	"github.com/anthropics/anthropic-sdk-go" // imported as anthropic
)

Sources: README.md:16-30

Local Development from Source

To use a local version of the library (e.g., for debugging or contributing), use a replace directive in your go.mod file:

go mod edit -replace github.com/anthropics/anthropic-sdk-go=/path/to/anthropic-sdk-go

Sources: CONTRIBUTING.md:28-32

Client Configuration

The SDK uses a client-based architecture. You initialize a client to manage connections, authentication, and request parameters.

Authentication Methods

The SDK supports multiple authentication strategies depending on the target environment:

Method	Environment Variable	Option / Helper
Anthropic API Key	ANTHROPIC_API_KEY	option.WithAPIKey("key")
AWS Bedrock	AWS_REGION, AWS_BEARER_TOKEN_BEDROCK	bedrock.WithLoadDefaultConfig(ctx)
Google Vertex AI	N/A	vertex.WithGoogleAuth(ctx, region, projectID)

Sources: README.md:34-40, examples/bedrock/main.go:13-15, examples/vertex/main.go:13-15, usage_test.go:27-30

Basic Client Initialization

The following diagram illustrates the flow of initializing a client and preparing it for a request.

This diagram shows the decision paths for configuring the SDK client based on the chosen provider.

Sources: README.md:34-40, examples/bedrock/main.go:13-15, examples/vertex/main.go:13-15

Quickstart Example

A basic interaction involves creating a client and sending a message to the Messages service.

package main

import (
	"context"
	"fmt"

	"github.com/anthropics/anthropic-sdk-go"
	"github.com/anthropics/anthropic-sdk-go/option"
)

func main() {
	// Initialize client
	client := anthropic.NewClient(
		option.WithAPIKey("my-anthropic-api-key"),
	)

	// Create a message
	message, err := client.Messages.New(context.TODO(), anthropic.MessageNewParams{
		MaxTokens: 1024,
		Messages: []anthropic.MessageParam{
			anthropic.NewUserMessage(anthropic.NewTextBlock("What is a quaternion?")),
		},
		Model: anthropic.ModelClaudeOpus4_6,
	})
	if err != nil {
		panic(err.Error())
	}

	// Output result
	fmt.Printf("%+v\n", message.Content)
}

Key Components in Quickstart

1. anthropic.NewClient: Constructs the central interface for all API calls.
2. anthropic.MessageNewParams: A struct used to define the request, including Model, MaxTokens, and the Messages list.
3. anthropic.NewUserMessage: A helper function to create a message with the "user" role.
4. anthropic.NewTextBlock: Encapsulates text content within a message block.

Sources: README.md:34-60, examples/message/main.go:10-25

Development Workflow

For developers contributing to or testing the SDK, the repository includes utility scripts.

Environment Setup

Run the bootstrap script to install dependencies:

./scripts/bootstrap
./scripts/lint

Running Examples

The SDK includes an examples/ directory with various use cases. You can run them directly:

go run ./examples/message

Sources: CONTRIBUTING.md:7-12, CONTRIBUTING.md:21-25

Testing

Most tests require a mock server. The project recommends using a server based on the OpenAPI spec.

./scripts/mock
./scripts/test

Sources: CONTRIBUTING.md:34-40

Summary

To get started with the Anthropic SDK for Go, ensure you have Go 1.22+ installed, add the dependency via go get, and initialize an anthropic.Client with your API key. The SDK provides a type-safe way to interact with Claude models, supporting both direct Anthropic API access and cloud-provider integrations like AWS Bedrock and Vertex AI.