fix(gemini): Implement Gemini 3 thought_signature handling for stateful reasoning

Dockerfile

@@ -3,34 +3,39 @@
 # ============================================================
 FROM golang:1.26.0-alpine AS builder
 
-RUN apk add --no-cache git make
+# Install build dependencies
+RUN apk add --no-cache git make gcc musl-dev
 
 WORKDIR /src
 
-# Cache dependencies
+# Cache dependencies for faster subsequent builds
 COPY go.mod go.sum ./
 RUN go mod download
 
-# Copy source and build
+# Copy your local source code (where you'll add the Thought Signature fix)
 COPY . .
+
+# Compile the binary
 RUN make build
 
 # ============================================================
 # Stage 2: Minimal runtime image
 # ============================================================
 FROM alpine:3.23
 
+# Install runtime essentials
 RUN apk add --no-cache ca-certificates tzdata curl
 
 # Health check
 HEALTHCHECK --interval=30s --timeout=3s --start-period=5s --retries=3 \
   CMD wget -q --spider http://localhost:18790/health || exit 1
 
-# Copy binary
+# Copy the compiled binary from the builder stage
 COPY --from=builder /src/build/picoclaw /usr/local/bin/picoclaw
 
-# Create picoclaw home directory
+# Create necessary directories and initialize
 RUN /usr/local/bin/picoclaw onboard
 
+# Set the binary as the entrypoint
 ENTRYPOINT ["picoclaw"]
-CMD ["gateway"]
+CMD ["gateway"]

pkg/agent/loop.go

@@ -621,13 +621,19 @@ func (al *AgentLoop) runLLMIteration(ctx context.Context, messages []providers.M
 		}
 		for _, tc := range response.ToolCalls {
 			argumentsJSON, _ := json.Marshal(tc.Arguments)
+			// Copy ExtraContent to ensure thought_signature is persisted
+			extraContent := tc.ExtraContent
+
 			assistantMsg.ToolCalls = append(assistantMsg.ToolCalls, providers.ToolCall{
 				ID:   tc.ID,
 				Type: "function",
 				Function: &providers.FunctionCall{
-					Name:      tc.Name,
-					Arguments: string(argumentsJSON),
+					Name:             tc.Name,
+					Arguments:        string(argumentsJSON),
 				},
+				ExtraContent: extraContent,
+				// We also set internal ThoughtSignature, but ExtraContent is what matters for serialization
+				ThoughtSignature: tc.ThoughtSignature, 
 			})
 		}
 		messages = append(messages, assistantMsg)

pkg/providers/http_provider.go

@@ -61,6 +61,8 @@ func (p *HTTPProvider) Chat(ctx context.Context, messages []Message, tools []Too
 		}
 	}
 
+	// Pre-process messages loop removed - relying on ExtraContent persistence in Agent Loop.
+
 	requestBody := map[string]interface{}{
 		"model":    model,
 		"messages": messages,
@@ -135,6 +137,11 @@ func (p *HTTPProvider) parseResponse(body []byte) (*LLMResponse, error) {
 						Name      string `json:"name"`
 						Arguments string `json:"arguments"`
 					} `json:"function"`
+					ExtraContent *struct {
+						Google *struct {
+							ThoughtSignature string `json:"thought_signature"`
+						} `json:"google"`
+					} `json:"extra_content"`
 				} `json:"tool_calls"`
 			} `json:"message"`
 			FinishReason string `json:"finish_reason"`
@@ -160,7 +167,12 @@ func (p *HTTPProvider) parseResponse(body []byte) (*LLMResponse, error) {
 		arguments := make(map[string]interface{})
 		name := ""
 
-		// Handle OpenAI format with nested function object
+		// Extract thought_signature from Gemini/Google-specific extra content
+		thoughtSignature := ""
+		if tc.ExtraContent != nil && tc.ExtraContent.Google != nil {
+			thoughtSignature = tc.ExtraContent.Google.ThoughtSignature
+		}
+
 		if tc.Type == "function" && tc.Function != nil {
 			name = tc.Function.Name
 			if tc.Function.Arguments != "" {
@@ -178,11 +190,23 @@ func (p *HTTPProvider) parseResponse(body []byte) (*LLMResponse, error) {
 			}
 		}
 
-		toolCalls = append(toolCalls, ToolCall{
-			ID:        tc.ID,
-			Name:      name,
-			Arguments: arguments,
-		})
+		// Correctly map extracted ExtraContent to ToolCall struct
+		toolCall := ToolCall{
+			ID:               tc.ID,
+			Name:             name,
+			Arguments:        arguments,
+			ThoughtSignature: thoughtSignature, // Populating internal field for convenience
+		}
+
+		if thoughtSignature != "" {
+			toolCall.ExtraContent = &ExtraContent{
+				Google: &GoogleExtra{
+					ThoughtSignature: thoughtSignature,
+				},
+			}
+		}
+
+		toolCalls = append(toolCalls, toolCall)
 	}
 
 	return &LLMResponse{

pkg/providers/types.go

@@ -3,16 +3,27 @@ package providers
 import "context"
 
 type ToolCall struct {
-	ID        string                 `json:"id"`
-	Type      string                 `json:"type,omitempty"`
-	Function  *FunctionCall          `json:"function,omitempty"`
-	Name      string                 `json:"name,omitempty"`
-	Arguments map[string]interface{} `json:"arguments,omitempty"`
+	ID               string                 `json:"id"`
+	Type             string                 `json:"type,omitempty"`
+	Function         *FunctionCall          `json:"function,omitempty"`
+	Name             string                 `json:"name,omitempty"`
+	Arguments        map[string]interface{} `json:"arguments,omitempty"`
+	ThoughtSignature string                 `json:"-"` // Internal use only
+	ExtraContent     *ExtraContent          `json:"extra_content,omitempty"`
+}
+
+type ExtraContent struct {
+	Google *GoogleExtra `json:"google,omitempty"`
+}
+
+type GoogleExtra struct {
+	ThoughtSignature string `json:"thought_signature,omitempty"`
 }
 
 type FunctionCall struct {
-	Name      string `json:"name"`
-	Arguments string `json:"arguments"`
+	Name             string `json:"name"`
+	Arguments        string `json:"arguments"`
+	ThoughtSignature string `json:"-"` // Internal use only
 }
 
 type LLMResponse struct {