// Package aichannel provides an interface for communicating with AI coding agents.
package aichannel
import (
"context"
"fmt"
"os"
"strings"
"github.com/anthropics/anthropic-sdk-go"
"github.com/anthropics/anthropic-sdk-go/option"
)
// AnthropicProvider implements the Provider interface using the Anthropic API.
type AnthropicProvider struct {
client anthropic.Client
config ProviderConfig
}
// Default Anthropic models
const (
AnthropicModelSonnet = "claude-sonnet-4-5-20250929"
AnthropicModelHaiku = "claude-haiku-3-5-20241022"
AnthropicModelOpus = "claude-opus-4-5-20251101"
)
// NewAnthropicProvider creates a new Anthropic API provider.
// If apiKey is empty, it will try environment variables in order:
// ANTHROPIC_API_KEY, CLAUDE_KEY
func NewAnthropicProvider(config ProviderConfig) *AnthropicProvider {
// Use environment variable if no API key provided
apiKey := config.APIKey
if apiKey == "" {
apiKey = os.Getenv("ANTHROPIC_API_KEY")
}
if apiKey == "" {
apiKey = os.Getenv("CLAUDE_KEY")
}
// Set defaults
if config.Model == "" {
config.Model = AnthropicModelSonnet
}
if config.MaxTokens == 0 {
config.MaxTokens = 1024
}
// Build client options
opts := []option.RequestOption{}
if apiKey != "" {
opts = append(opts, option.WithAPIKey(apiKey))
}
if config.BaseURL != "" {
opts = append(opts, option.WithBaseURL(config.BaseURL))
}
return &AnthropicProvider{
client: anthropic.NewClient(opts...),
config: config,
}
}
// Name returns the provider name.
func (p *AnthropicProvider) Name() string {
return "anthropic"
}
// IsConfigured returns true if the provider has an API key.
func (p *AnthropicProvider) IsConfigured() bool {
// Check if API key is available (either from config or env)
return p.config.APIKey != "" ||
os.Getenv("ANTHROPIC_API_KEY") != "" ||
os.Getenv("CLAUDE_KEY") != ""
}
// Complete sends a prompt and returns the completion.
func (p *AnthropicProvider) Complete(ctx context.Context, systemPrompt, userPrompt string) (*Response, error) {
return p.CompleteWithContext(ctx, systemPrompt, userPrompt, "")
}
// CompleteWithContext sends a prompt with additional context and returns the completion.
func (p *AnthropicProvider) CompleteWithContext(ctx context.Context, systemPrompt, userPrompt, inputContext string) (*Response, error) {
if !p.IsConfigured() {
return nil, ErrNoAPIKey
}
// Build user message content
var userContent string
if inputContext != "" {
userContent = fmt.Sprintf("<context>\n%s\n</context>\n\n%s", inputContext, userPrompt)
} else {
userContent = userPrompt
}
// Build message params
params := anthropic.MessageNewParams{
Model: anthropic.Model(p.config.Model),
MaxTokens: int64(p.config.MaxTokens),
Messages: []anthropic.MessageParam{
anthropic.NewUserMessage(anthropic.NewTextBlock(userContent)),
},
}
// Add system prompt if provided
if systemPrompt != "" {
params.System = []anthropic.TextBlockParam{
{Text: systemPrompt},
}
}
// Make the API call
message, err := p.client.Messages.New(ctx, params)
if err != nil {
return nil, fmt.Errorf("%w: %v", ErrProviderError, err)
}
// Extract text from response
var resultText strings.Builder
for _, block := range message.Content {
if block.Type == "text" {
resultText.WriteString(block.Text)
}
}
return &Response{
Result: strings.TrimSpace(resultText.String()),
SessionID: message.ID,
// Anthropic doesn't provide cost directly, but we can estimate from usage
// message.Usage.InputTokens and message.Usage.OutputTokens
}, nil
}
// Model returns the configured model name.
func (p *AnthropicProvider) Model() string {
return p.config.Model
}
// SetModel updates the model to use.
func (p *AnthropicProvider) SetModel(model string) {
p.config.Model = model
}
