anthropic.go

  1package provider
  2
  3import (
  4	"context"
  5	"encoding/json"
  6	"errors"
  7	"fmt"
  8	"io"
  9	"strings"
 10	"time"
 11
 12	"github.com/anthropics/anthropic-sdk-go"
 13	"github.com/anthropics/anthropic-sdk-go/bedrock"
 14	"github.com/anthropics/anthropic-sdk-go/option"
 15	"github.com/opencode-ai/opencode/internal/config"
 16	"github.com/opencode-ai/opencode/internal/llm/tools"
 17	"github.com/opencode-ai/opencode/internal/logging"
 18	"github.com/opencode-ai/opencode/internal/message"
 19)
 20
 21type anthropicOptions struct {
 22	useBedrock   bool
 23	disableCache bool
 24	shouldThink  func(userMessage string) bool
 25}
 26
 27type AnthropicOption func(*anthropicOptions)
 28
 29type anthropicClient struct {
 30	providerOptions providerClientOptions
 31	options         anthropicOptions
 32	client          anthropic.Client
 33}
 34
 35type AnthropicClient ProviderClient
 36
 37func newAnthropicClient(opts providerClientOptions) AnthropicClient {
 38	anthropicOpts := anthropicOptions{}
 39	for _, o := range opts.anthropicOptions {
 40		o(&anthropicOpts)
 41	}
 42
 43	anthropicClientOptions := []option.RequestOption{}
 44	if opts.apiKey != "" {
 45		anthropicClientOptions = append(anthropicClientOptions, option.WithAPIKey(opts.apiKey))
 46	}
 47	if anthropicOpts.useBedrock {
 48		anthropicClientOptions = append(anthropicClientOptions, bedrock.WithLoadDefaultConfig(context.Background()))
 49	}
 50
 51	client := anthropic.NewClient(anthropicClientOptions...)
 52	return &anthropicClient{
 53		providerOptions: opts,
 54		options:         anthropicOpts,
 55		client:          client,
 56	}
 57}
 58
 59func (a *anthropicClient) convertMessages(messages []message.Message) (anthropicMessages []anthropic.MessageParam) {
 60	for i, msg := range messages {
 61		cache := false
 62		if i > len(messages)-3 {
 63			cache = true
 64		}
 65		switch msg.Role {
 66		case message.User:
 67			content := anthropic.NewTextBlock(msg.Content().String())
 68			if cache && !a.options.disableCache {
 69				content.OfRequestTextBlock.CacheControl = anthropic.CacheControlEphemeralParam{
 70					Type: "ephemeral",
 71				}
 72			}
 73			anthropicMessages = append(anthropicMessages, anthropic.NewUserMessage(content))
 74
 75		case message.Assistant:
 76			blocks := []anthropic.ContentBlockParamUnion{}
 77			if msg.Content().String() != "" {
 78				content := anthropic.NewTextBlock(msg.Content().String())
 79				if cache && !a.options.disableCache {
 80					content.OfRequestTextBlock.CacheControl = anthropic.CacheControlEphemeralParam{
 81						Type: "ephemeral",
 82					}
 83				}
 84				blocks = append(blocks, content)
 85			}
 86
 87			for _, toolCall := range msg.ToolCalls() {
 88				var inputMap map[string]any
 89				err := json.Unmarshal([]byte(toolCall.Input), &inputMap)
 90				if err != nil {
 91					continue
 92				}
 93				blocks = append(blocks, anthropic.ContentBlockParamOfRequestToolUseBlock(toolCall.ID, inputMap, toolCall.Name))
 94			}
 95
 96			if len(blocks) == 0 {
 97				logging.Warn("There is a message without content, investigate, this should not happen")
 98				continue
 99			}
100			anthropicMessages = append(anthropicMessages, anthropic.NewAssistantMessage(blocks...))
101
102		case message.Tool:
103			results := make([]anthropic.ContentBlockParamUnion, len(msg.ToolResults()))
104			for i, toolResult := range msg.ToolResults() {
105				results[i] = anthropic.NewToolResultBlock(toolResult.ToolCallID, toolResult.Content, toolResult.IsError)
106			}
107			anthropicMessages = append(anthropicMessages, anthropic.NewUserMessage(results...))
108		}
109	}
110	return
111}
112
113func (a *anthropicClient) convertTools(tools []tools.BaseTool) []anthropic.ToolUnionParam {
114	anthropicTools := make([]anthropic.ToolUnionParam, len(tools))
115
116	for i, tool := range tools {
117		info := tool.Info()
118		toolParam := anthropic.ToolParam{
119			Name:        info.Name,
120			Description: anthropic.String(info.Description),
121			InputSchema: anthropic.ToolInputSchemaParam{
122				Properties: info.Parameters,
123				// TODO: figure out how we can tell claude the required fields?
124			},
125		}
126
127		if i == len(tools)-1 && !a.options.disableCache {
128			toolParam.CacheControl = anthropic.CacheControlEphemeralParam{
129				Type: "ephemeral",
130			}
131		}
132
133		anthropicTools[i] = anthropic.ToolUnionParam{OfTool: &toolParam}
134	}
135
136	return anthropicTools
137}
138
139func (a *anthropicClient) finishReason(reason string) message.FinishReason {
140	switch reason {
141	case "end_turn":
142		return message.FinishReasonEndTurn
143	case "max_tokens":
144		return message.FinishReasonMaxTokens
145	case "tool_use":
146		return message.FinishReasonToolUse
147	case "stop_sequence":
148		return message.FinishReasonEndTurn
149	default:
150		return message.FinishReasonUnknown
151	}
152}
153
154func (a *anthropicClient) preparedMessages(messages []anthropic.MessageParam, tools []anthropic.ToolUnionParam) anthropic.MessageNewParams {
155	var thinkingParam anthropic.ThinkingConfigParamUnion
156	lastMessage := messages[len(messages)-1]
157	isUser := lastMessage.Role == anthropic.MessageParamRoleUser
158	messageContent := ""
159	temperature := anthropic.Float(0)
160	if isUser {
161		for _, m := range lastMessage.Content {
162			if m.OfRequestTextBlock != nil && m.OfRequestTextBlock.Text != "" {
163				messageContent = m.OfRequestTextBlock.Text
164			}
165		}
166		if messageContent != "" && a.options.shouldThink != nil && a.options.shouldThink(messageContent) {
167			thinkingParam = anthropic.ThinkingConfigParamUnion{
168				OfThinkingConfigEnabled: &anthropic.ThinkingConfigEnabledParam{
169					BudgetTokens: int64(float64(a.providerOptions.maxTokens) * 0.8),
170					Type:         "enabled",
171				},
172			}
173			temperature = anthropic.Float(1)
174		}
175	}
176
177	return anthropic.MessageNewParams{
178		Model:       anthropic.Model(a.providerOptions.model.APIModel),
179		MaxTokens:   a.providerOptions.maxTokens,
180		Temperature: temperature,
181		Messages:    messages,
182		Tools:       tools,
183		Thinking:    thinkingParam,
184		System: []anthropic.TextBlockParam{
185			{
186				Text: a.providerOptions.systemMessage,
187				CacheControl: anthropic.CacheControlEphemeralParam{
188					Type: "ephemeral",
189				},
190			},
191		},
192	}
193}
194
195func (a *anthropicClient) send(ctx context.Context, messages []message.Message, tools []tools.BaseTool) (resposne *ProviderResponse, err error) {
196	preparedMessages := a.preparedMessages(a.convertMessages(messages), a.convertTools(tools))
197	cfg := config.Get()
198	if cfg.Debug {
199		// jsonData, _ := json.Marshal(preparedMessages)
200		// logging.Debug("Prepared messages", "messages", string(jsonData))
201	}
202	attempts := 0
203	for {
204		attempts++
205		anthropicResponse, err := a.client.Messages.New(
206			ctx,
207			preparedMessages,
208		)
209		// If there is an error we are going to see if we can retry the call
210		if err != nil {
211			retry, after, retryErr := a.shouldRetry(attempts, err)
212			if retryErr != nil {
213				return nil, retryErr
214			}
215			if retry {
216				logging.WarnPersist(fmt.Sprintf("Retrying due to rate limit... attempt %d of %d", attempts, maxRetries), logging.PersistTimeArg, time.Millisecond*time.Duration(after+100))
217				select {
218				case <-ctx.Done():
219					return nil, ctx.Err()
220				case <-time.After(time.Duration(after) * time.Millisecond):
221					continue
222				}
223			}
224			return nil, retryErr
225		}
226
227		content := ""
228		for _, block := range anthropicResponse.Content {
229			if text, ok := block.AsAny().(anthropic.TextBlock); ok {
230				content += text.Text
231			}
232		}
233
234		return &ProviderResponse{
235			Content:   content,
236			ToolCalls: a.toolCalls(*anthropicResponse),
237			Usage:     a.usage(*anthropicResponse),
238		}, nil
239	}
240}
241
242func (a *anthropicClient) stream(ctx context.Context, messages []message.Message, tools []tools.BaseTool) <-chan ProviderEvent {
243	preparedMessages := a.preparedMessages(a.convertMessages(messages), a.convertTools(tools))
244	cfg := config.Get()
245	if cfg.Debug {
246		// jsonData, _ := json.Marshal(preparedMessages)
247		// logging.Debug("Prepared messages", "messages", string(jsonData))
248	}
249	attempts := 0
250	eventChan := make(chan ProviderEvent)
251	go func() {
252		for {
253			attempts++
254			anthropicStream := a.client.Messages.NewStreaming(
255				ctx,
256				preparedMessages,
257			)
258			accumulatedMessage := anthropic.Message{}
259
260			currentToolCallID := ""
261			for anthropicStream.Next() {
262				event := anthropicStream.Current()
263				err := accumulatedMessage.Accumulate(event)
264				if err != nil {
265					logging.Warn("Error accumulating message", "error", err)
266					continue
267				}
268
269				switch event := event.AsAny().(type) {
270				case anthropic.ContentBlockStartEvent:
271					if event.ContentBlock.Type == "text" {
272						eventChan <- ProviderEvent{Type: EventContentStart}
273					} else if event.ContentBlock.Type == "tool_use" {
274						currentToolCallID = event.ContentBlock.ID
275						eventChan <- ProviderEvent{
276							Type: EventToolUseStart,
277							ToolCall: &message.ToolCall{
278								ID:       event.ContentBlock.ID,
279								Name:     event.ContentBlock.Name,
280								Finished: false,
281							},
282						}
283					}
284
285				case anthropic.ContentBlockDeltaEvent:
286					if event.Delta.Type == "thinking_delta" && event.Delta.Thinking != "" {
287						eventChan <- ProviderEvent{
288							Type:     EventThinkingDelta,
289							Thinking: event.Delta.Thinking,
290						}
291					} else if event.Delta.Type == "text_delta" && event.Delta.Text != "" {
292						eventChan <- ProviderEvent{
293							Type:    EventContentDelta,
294							Content: event.Delta.Text,
295						}
296					} else if event.Delta.Type == "input_json_delta" {
297						if currentToolCallID != "" {
298							eventChan <- ProviderEvent{
299								Type: EventToolUseDelta,
300								ToolCall: &message.ToolCall{
301									ID:       currentToolCallID,
302									Finished: false,
303									Input:    event.Delta.JSON.PartialJSON.Raw(),
304								},
305							}
306						}
307					}
308				case anthropic.ContentBlockStopEvent:
309					if currentToolCallID != "" {
310						eventChan <- ProviderEvent{
311							Type: EventToolUseStop,
312							ToolCall: &message.ToolCall{
313								ID: currentToolCallID,
314							},
315						}
316						currentToolCallID = ""
317					} else {
318						eventChan <- ProviderEvent{Type: EventContentStop}
319					}
320
321				case anthropic.MessageStopEvent:
322					content := ""
323					for _, block := range accumulatedMessage.Content {
324						if text, ok := block.AsAny().(anthropic.TextBlock); ok {
325							content += text.Text
326						}
327					}
328
329					eventChan <- ProviderEvent{
330						Type: EventComplete,
331						Response: &ProviderResponse{
332							Content:      content,
333							ToolCalls:    a.toolCalls(accumulatedMessage),
334							Usage:        a.usage(accumulatedMessage),
335							FinishReason: a.finishReason(string(accumulatedMessage.StopReason)),
336						},
337					}
338				}
339			}
340
341			err := anthropicStream.Err()
342			if err == nil || errors.Is(err, io.EOF) {
343				close(eventChan)
344				return
345			}
346			// If there is an error we are going to see if we can retry the call
347			retry, after, retryErr := a.shouldRetry(attempts, err)
348			if retryErr != nil {
349				eventChan <- ProviderEvent{Type: EventError, Error: retryErr}
350				close(eventChan)
351				return
352			}
353			if retry {
354				logging.WarnPersist(fmt.Sprintf("Retrying due to rate limit... attempt %d of %d", attempts, maxRetries), logging.PersistTimeArg, time.Millisecond*time.Duration(after+100))
355				select {
356				case <-ctx.Done():
357					// context cancelled
358					if ctx.Err() != nil {
359						eventChan <- ProviderEvent{Type: EventError, Error: ctx.Err()}
360					}
361					close(eventChan)
362					return
363				case <-time.After(time.Duration(after) * time.Millisecond):
364					continue
365				}
366			}
367			if ctx.Err() != nil {
368				eventChan <- ProviderEvent{Type: EventError, Error: ctx.Err()}
369			}
370
371			close(eventChan)
372			return
373		}
374	}()
375	return eventChan
376}
377
378func (a *anthropicClient) shouldRetry(attempts int, err error) (bool, int64, error) {
379	var apierr *anthropic.Error
380	if !errors.As(err, &apierr) {
381		return false, 0, err
382	}
383
384	if apierr.StatusCode != 429 && apierr.StatusCode != 529 {
385		return false, 0, err
386	}
387
388	if attempts > maxRetries {
389		return false, 0, fmt.Errorf("maximum retry attempts reached for rate limit: %d retries", maxRetries)
390	}
391
392	retryMs := 0
393	retryAfterValues := apierr.Response.Header.Values("Retry-After")
394
395	backoffMs := 2000 * (1 << (attempts - 1))
396	jitterMs := int(float64(backoffMs) * 0.2)
397	retryMs = backoffMs + jitterMs
398	if len(retryAfterValues) > 0 {
399		if _, err := fmt.Sscanf(retryAfterValues[0], "%d", &retryMs); err == nil {
400			retryMs = retryMs * 1000
401		}
402	}
403	return true, int64(retryMs), nil
404}
405
406func (a *anthropicClient) toolCalls(msg anthropic.Message) []message.ToolCall {
407	var toolCalls []message.ToolCall
408
409	for _, block := range msg.Content {
410		switch variant := block.AsAny().(type) {
411		case anthropic.ToolUseBlock:
412			toolCall := message.ToolCall{
413				ID:       variant.ID,
414				Name:     variant.Name,
415				Input:    string(variant.Input),
416				Type:     string(variant.Type),
417				Finished: true,
418			}
419			toolCalls = append(toolCalls, toolCall)
420		}
421	}
422
423	return toolCalls
424}
425
426func (a *anthropicClient) usage(msg anthropic.Message) TokenUsage {
427	return TokenUsage{
428		InputTokens:         msg.Usage.InputTokens,
429		OutputTokens:        msg.Usage.OutputTokens,
430		CacheCreationTokens: msg.Usage.CacheCreationInputTokens,
431		CacheReadTokens:     msg.Usage.CacheReadInputTokens,
432	}
433}
434
435func WithAnthropicBedrock(useBedrock bool) AnthropicOption {
436	return func(options *anthropicOptions) {
437		options.useBedrock = useBedrock
438	}
439}
440
441func WithAnthropicDisableCache() AnthropicOption {
442	return func(options *anthropicOptions) {
443		options.disableCache = true
444	}
445}
446
447func DefaultShouldThinkFn(s string) bool {
448	return strings.Contains(strings.ToLower(s), "think")
449}
450
451func WithAnthropicShouldThinkFn(fn func(string) bool) AnthropicOption {
452	return func(options *anthropicOptions) {
453		options.shouldThink = fn
454	}
455}