@@ -6,6 +6,8 @@ import (
11 "github.com/anthropics/anthropic-sdk-go"
13 "github.com/anthropics/anthropic-sdk-go"
@@ -19,9 +21,10 @@ import (
21type anthropicClient struct {
23type anthropicClient struct {
22− providerOptions providerClientOptions
24+ providerOptions providerClientOptions
23− useBedrock bool
25+ useBedrock bool
24− client anthropic.Client
26+ client anthropic.Client
27+ adjustedMaxTokens int // Used when context limit is hit
27type AnthropicClient ProviderClient
30type AnthropicClient ProviderClient
@@ -171,6 +174,11 @@ func (a *anthropicClient) preparedMessages(messages []anthropic.MessageParam, to
171 maxTokens = a.providerOptions.maxTokens
174 maxTokens = a.providerOptions.maxTokens
177+ // Use adjusted max tokens if context limit was hit
178+ if a.adjustedMaxTokens > 0 {
179+ maxTokens = int64(a.adjustedMaxTokens)
174 return anthropic.MessageNewParams{
182 return anthropic.MessageNewParams{
175 Model: anthropic.Model(model.ID),
183 Model: anthropic.Model(model.ID),
176 MaxTokens: maxTokens,
184 MaxTokens: maxTokens,
@@ -190,16 +198,18 @@ func (a *anthropicClient) preparedMessages(messages []anthropic.MessageParam, to
192func (a *anthropicClient) send(ctx context.Context, messages []message.Message, tools []tools.BaseTool) (response *ProviderResponse, err error) {
200func (a *anthropicClient) send(ctx context.Context, messages []message.Message, tools []tools.BaseTool) (response *ProviderResponse, err error) {
193− preparedMessages := a.preparedMessages(a.convertMessages(messages), a.convertTools(tools))
194 cfg := config.Get()
201 cfg := config.Get()
195− if cfg.Options.Debug {
196− jsonData, _ := json.Marshal(preparedMessages)
197− logging.Debug("Prepared messages", "messages", string(jsonData))
200 attempts := 0
203 attempts := 0
202 attempts++
205 attempts++
206+ // Prepare messages on each attempt in case max_tokens was adjusted
207+ preparedMessages := a.preparedMessages(a.convertMessages(messages), a.convertTools(tools))
208+ if cfg.Options.Debug {
209+ jsonData, _ := json.Marshal(preparedMessages)
210+ logging.Debug("Prepared messages", "messages", string(jsonData))
203 anthropicResponse, err := a.client.Messages.New(
213 anthropicResponse, err := a.client.Messages.New(
205 preparedMessages,
215 preparedMessages,
@@ -239,17 +249,19 @@ func (a *anthropicClient) send(ctx context.Context, messages []message.Message,
241func (a *anthropicClient) stream(ctx context.Context, messages []message.Message, tools []tools.BaseTool) <-chan ProviderEvent {
251func (a *anthropicClient) stream(ctx context.Context, messages []message.Message, tools []tools.BaseTool) <-chan ProviderEvent {
242− preparedMessages := a.preparedMessages(a.convertMessages(messages), a.convertTools(tools))
243 cfg := config.Get()
252 cfg := config.Get()
244− if cfg.Options.Debug {
245− // jsonData, _ := json.Marshal(preparedMessages)
246− // logging.Debug("Prepared messages", "messages", string(jsonData))
248 attempts := 0
253 attempts := 0
249 eventChan := make(chan ProviderEvent)
254 eventChan := make(chan ProviderEvent)
250 go func() {
255 go func() {
252 attempts++
257 attempts++
258+ // Prepare messages on each attempt in case max_tokens was adjusted
259+ preparedMessages := a.preparedMessages(a.convertMessages(messages), a.convertTools(tools))
260+ if cfg.Options.Debug {
261+ jsonData, _ := json.Marshal(preparedMessages)
262+ logging.Debug("Prepared messages", "messages", string(jsonData))
253 anthropicStream := a.client.Messages.NewStreaming(
265 anthropicStream := a.client.Messages.NewStreaming(
255 preparedMessages,
267 preparedMessages,
@@ -395,6 +407,15 @@ func (a *anthropicClient) shouldRetry(attempts int, err error) (bool, int64, err
395 return true, 0, nil
407 return true, 0, nil
410+ // Handle context limit exceeded error (400 Bad Request)
411+ if apiErr.StatusCode == 400 {
412+ if adjusted, ok := a.handleContextLimitError(apiErr); ok {
413+ a.adjustedMaxTokens = adjusted
414+ logging.Debug("Adjusted max_tokens due to context limit", "new_max_tokens", adjusted)
398 if apiErr.StatusCode != 429 && apiErr.StatusCode != 529 {
419 if apiErr.StatusCode != 429 && apiErr.StatusCode != 529 {
399 return false, 0, err
420 return false, 0, err
@@ -413,6 +434,33 @@ func (a *anthropicClient) shouldRetry(attempts int, err error) (bool, int64, err
413 return true, int64(retryMs), nil
434 return true, int64(retryMs), nil
437+// handleContextLimitError parses context limit error and returns adjusted max_tokens
438+func (a *anthropicClient) handleContextLimitError(apiErr *anthropic.Error) (int, bool) {
439+ // Parse error message like: "input length and max_tokens exceed context limit: 154978 + 50000 > 200000"
440+ errorMsg := apiErr.Error()
441+ re := regexp.MustCompile(`input length and max_tokens exceed context limit: (\d+) \+ (\d+) > (\d+)`)
442+ matches := re.FindStringSubmatch(errorMsg)
444+ if len(matches) != 4 {
448+ inputTokens, err1 := strconv.Atoi(matches[1])
449+ contextLimit, err2 := strconv.Atoi(matches[3])
451+ if err1 != nil || err2 != nil {
455+ // Calculate safe max_tokens with a buffer of 1000 tokens
456+ safeMaxTokens := contextLimit - inputTokens - 1000
458+ // Ensure we don't go below a minimum threshold
459+ safeMaxTokens = max(safeMaxTokens, 1000)
461+ return safeMaxTokens, true
416func (a *anthropicClient) toolCalls(msg anthropic.Message) []message.ToolCall {
464func (a *anthropicClient) toolCalls(msg anthropic.Message) []message.ToolCall {
417 var toolCalls []message.ToolCall
465 var toolCalls []message.ToolCall