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fix: keep anthropic thinking signatures on the same block #5

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Merged
whtsky merged 1 commit into from
Apr 16, 2026
Merged

fix: keep anthropic thinking signatures on the same block #5

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71 changes: 55 additions & 16 deletions anthropic/stream.go
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -154,9 +154,11 @@ func handleContent(delta OpenAIMessage, state *StreamState) []AnthropicStreamEve
content = *delta.Content.Text
}

// Close thinking block if open
signature := reasoningOpaque(delta)

// Close thinking block if open, attaching signature to the same block.
if state.ThinkingBlockOpen {
events = append(events, closeThinkingBlock(state)...)
events = append(events, closeThinkingBlock(state, signature)...)
}

// Close tool block if open
Expand Down Expand Up @@ -198,9 +200,13 @@ func handleContent(delta OpenAIMessage, state *StreamState) []AnthropicStreamEve
func handleToolCalls(delta OpenAIMessage, state *StreamState) []AnthropicStreamEvent {
var events []AnthropicStreamEvent

// Close thinking block if open
signature := reasoningOpaque(delta)
consumedThinkingSignature := false

// Close thinking block if open, attaching signature to the same block.
if state.ThinkingBlockOpen {
events = append(events, closeThinkingBlock(state)...)
events = append(events, closeThinkingBlock(state, signature)...)
consumedThinkingSignature = signature != ""
}

// Handle reasoning opaque in tool calls
Expand All @@ -213,9 +219,11 @@ func handleToolCalls(delta OpenAIMessage, state *StreamState) []AnthropicStreamE
state.ContentBlockOpen = false
}

// Handle reasoning opaque
if delta.ReasoningOpaque != nil && *delta.ReasoningOpaque != "" {
events = append(events, handleReasoningOpaque(delta, state)...)
// Handle reasoning opaque only when there was no open thinking block to attach it to.
if !consumedThinkingSignature && !state.ThinkingBlockOpen {
if signature != "" {
events = append(events, handleReasoningOpaque(signature, state)...)
}
}

for _, toolCall := range delta.ToolCalls {
Expand Down Expand Up @@ -286,9 +294,13 @@ func handleToolCalls(delta OpenAIMessage, state *StreamState) []AnthropicStreamE
func handleFinish(choice OpenAIChunkChoice, chunk OpenAIChatCompletionChunk, state *StreamState) []AnthropicStreamEvent {
var events []AnthropicStreamEvent

// Close thinking block if open
signature := reasoningOpaque(choice.Delta)
consumedThinkingSignature := false

// Close thinking block if open, attaching signature to the same block.
if state.ThinkingBlockOpen {
events = append(events, closeThinkingBlock(state)...)
events = append(events, closeThinkingBlock(state, signature)...)
consumedThinkingSignature = signature != ""
}

// Close any open content block
Expand All @@ -304,9 +316,11 @@ func handleFinish(choice OpenAIChunkChoice, chunk OpenAIChatCompletionChunk, sta
state.ContentBlockOpen = false
state.ContentBlockIndex++

// Handle reasoning opaque for non-tool blocks
if !toolBlockOpen {
events = append(events, handleReasoningOpaque(choice.Delta, state)...)
// Handle reasoning opaque for non-tool blocks when there was no open thinking block.
if !toolBlockOpen && !consumedThinkingSignature {
if signature != "" {
events = append(events, handleReasoningOpaque(signature, state)...)
}
}
}

Expand Down Expand Up @@ -344,10 +358,10 @@ func handleFinish(choice OpenAIChunkChoice, chunk OpenAIChatCompletionChunk, sta
return events
}

func handleReasoningOpaque(delta OpenAIMessage, state *StreamState) []AnthropicStreamEvent {
func handleReasoningOpaque(signature string, state *StreamState) []AnthropicStreamEvent {
var events []AnthropicStreamEvent

if delta.ReasoningOpaque != nil && *delta.ReasoningOpaque != "" {
if signature != "" {
events = append(events,
AnthropicStreamEvent{
Type: "content_block_start",
Expand All @@ -357,12 +371,20 @@ func handleReasoningOpaque(delta OpenAIMessage, state *StreamState) []AnthropicS
Thinking: "",
},
},
AnthropicStreamEvent{
Type: "content_block_delta",
Index: intPtr(state.ContentBlockIndex),
Delta: &AnthropicContentDelta{
Type: "thinking_delta",
Thinking: "",
},
},
AnthropicStreamEvent{
Type: "content_block_delta",
Index: intPtr(state.ContentBlockIndex),
Delta: &AnthropicContentDelta{
Type: "signature_delta",
Signature: *delta.ReasoningOpaque,
Signature: signature,
},
},
AnthropicStreamEvent{
Expand All @@ -376,10 +398,20 @@ func handleReasoningOpaque(delta OpenAIMessage, state *StreamState) []AnthropicS
return events
}

func closeThinkingBlock(state *StreamState) []AnthropicStreamEvent {
func closeThinkingBlock(state *StreamState, signature string) []AnthropicStreamEvent {
var events []AnthropicStreamEvent

if state.ThinkingBlockOpen {
if signature != "" {
events = append(events, AnthropicStreamEvent{
Type: "content_block_delta",
Index: intPtr(state.ContentBlockIndex),
Delta: &AnthropicContentDelta{
Type: "signature_delta",
Signature: signature,
},
})
}
events = append(events,
AnthropicStreamEvent{
Type: "content_block_stop",
Expand All @@ -393,6 +425,13 @@ func closeThinkingBlock(state *StreamState) []AnthropicStreamEvent {
return events
}

func reasoningOpaque(delta OpenAIMessage) string {
if delta.ReasoningOpaque != nil {
return *delta.ReasoningOpaque
}
return ""
}

func isToolBlockOpen(state *StreamState) bool {
if !state.ContentBlockOpen {
return false
Expand Down
124 changes: 124 additions & 0 deletions anthropic/stream_test.go
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Original file line number Diff line number Diff line change
Expand Up @@ -361,6 +361,130 @@ func TestConvertOpenAIChunkToAnthropicEvents_Finish(t *testing.T) {
}
}

func TestConvertOpenAIChunkToAnthropicEvents_ThinkingFinishWithSignature(t *testing.T) {
state := NewStreamState()
state.MessageStartSent = true

thinkingChunk := OpenAIChatCompletionChunk{
ID: "msg_123",
Model: "claude-3-sonnet-20240229",
Choices: []OpenAIChunkChoice{{
Index: 0,
Delta: OpenAIMessage{
ReasoningText: stringPtr("Let me think about this..."),
},
}},
}
if _, err := ConvertOpenAIChunkToAnthropicEvents(thinkingChunk, state); err != nil {
t.Fatalf("Thinking conversion failed: %v", err)
}

finishChunk := OpenAIChatCompletionChunk{
ID: "msg_123",
Model: "claude-3-sonnet-20240229",
Choices: []OpenAIChunkChoice{{
Index: 0,
Delta: OpenAIMessage{
ReasoningOpaque: stringPtr("sig_123"),
},
FinishReason: "stop",
}},
Usage: &OpenAIUsage{PromptTokens: 10, CompletionTokens: 25},
}

events, err := ConvertOpenAIChunkToAnthropicEvents(finishChunk, state)
if err != nil {
t.Fatalf("Finish conversion failed: %v", err)
}

if len(events) != 4 {
t.Fatalf("Expected 4 events (signature + stop + delta + stop), got %d", len(events))
}

cd := contentDelta(t, events[0])
if cd.Type != "signature_delta" {
t.Fatalf("Expected first delta to be signature_delta, got %q", cd.Type)
}
if cd.Signature != "sig_123" {
t.Fatalf("Expected signature sig_123, got %q", cd.Signature)
}

if events[1].Type != "content_block_stop" {
t.Fatalf("Expected second event content_block_stop, got %q", events[1].Type)
}
if events[2].Type != "message_delta" {
t.Fatalf("Expected third event message_delta, got %q", events[2].Type)
}
if events[3].Type != "message_stop" {
t.Fatalf("Expected fourth event message_stop, got %q", events[3].Type)
}
}

func TestConvertOpenAIChunkToAnthropicEvents_ThinkingToToolCallWithSignature(t *testing.T) {
state := NewStreamState()
state.MessageStartSent = true

thinkingChunk := OpenAIChatCompletionChunk{
ID: "msg_123",
Model: "claude-3-sonnet-20240229",
Choices: []OpenAIChunkChoice{{
Index: 0,
Delta: OpenAIMessage{
ReasoningText: stringPtr("Analyzing..."),
},
}},
}
if _, err := ConvertOpenAIChunkToAnthropicEvents(thinkingChunk, state); err != nil {
t.Fatalf("Thinking conversion failed: %v", err)
}

toolChunk := OpenAIChatCompletionChunk{
ID: "msg_123",
Model: "claude-3-sonnet-20240229",
Choices: []OpenAIChunkChoice{{
Index: 0,
Delta: OpenAIMessage{
ReasoningOpaque: stringPtr("sig_456"),
ToolCalls: []OpenAIToolCall{{
Index: intPtr(0),
ID: "call_1",
Function: OpenAIToolCallFunction{
Name: "search",
},
}},
},
}},
}

events, err := ConvertOpenAIChunkToAnthropicEvents(toolChunk, state)
if err != nil {
t.Fatalf("Tool conversion failed: %v", err)
}

if len(events) != 3 {
t.Fatalf("Expected 3 events (signature + stop + tool_start), got %d", len(events))
}

cd := contentDelta(t, events[0])
if cd.Type != "signature_delta" {
t.Fatalf("Expected first delta to be signature_delta, got %q", cd.Type)
}
if cd.Signature != "sig_456" {
t.Fatalf("Expected signature sig_456, got %q", cd.Signature)
}

if events[1].Type != "content_block_stop" {
t.Fatalf("Expected second event content_block_stop, got %q", events[1].Type)
}
if events[2].Type != "content_block_start" || events[2].ContentBlock == nil || events[2].ContentBlock.Type != "tool_use" {
t.Fatalf("Expected third event tool_use content_block_start, got %#v", events[2])
}

if events[2].Index == nil || *events[2].Index != 1 {
t.Fatalf("Expected tool block index 1, got %v", events[2].Index)
}
}

func TestConvertOpenAIChunkToAnthropicEvents_ComplexFlow(t *testing.T) {
state := NewStreamState()

Expand Down