Fix tool calling

internal/api/types.go

@@ -94,9 +94,10 @@ type InputItem struct {
 
 // Message is the normalized internal message representation.
 type Message struct {
-	Role    string         `json:"role"`
-	Content []ContentBlock `json:"content"`
-	CallID  string         `json:"call_id,omitempty"` // for tool messages
+	Role      string         `json:"role"`
+	Content   []ContentBlock `json:"content"`
+	CallID    string         `json:"call_id,omitempty"`    // for tool messages
+	ToolCalls []ToolCall     `json:"tool_calls,omitempty"` // for assistant messages
 }
 
 // ContentBlock is a typed content element.
@@ -129,9 +130,35 @@ func (r *ResponseRequest) NormalizeInput() []Message {
 					}
 					msg.Content = []ContentBlock{{Type: contentType, Text: s}}
 				} else {
-					var blocks []ContentBlock
-					_ = json.Unmarshal(item.Content, &blocks)
-					msg.Content = blocks
+					// Content is an array of blocks - parse them
+					var rawBlocks []map[string]interface{}
+					if err := json.Unmarshal(item.Content, &rawBlocks); err == nil {
+						// Extract content blocks and tool calls
+						for _, block := range rawBlocks {
+							blockType, _ := block["type"].(string)
+
+							if blockType == "tool_use" {
+								// Extract tool call information
+								toolCall := ToolCall{
+									ID:   getStringField(block, "id"),
+									Name: getStringField(block, "name"),
+								}
+								// input field contains the arguments as a map
+								if input, ok := block["input"].(map[string]interface{}); ok {
+									if inputJSON, err := json.Marshal(input); err == nil {
+										toolCall.Arguments = string(inputJSON)
+									}
+								}
+								msg.ToolCalls = append(msg.ToolCalls, toolCall)
+							} else if blockType == "output_text" || blockType == "input_text" {
+								// Regular text content block
+								msg.Content = append(msg.Content, ContentBlock{
+									Type: blockType,
+									Text: getStringField(block, "text"),
+								})
+							}
+						}
+					}
 				}
 			}
 			msgs = append(msgs, msg)
@@ -338,3 +365,11 @@ func (r *ResponseRequest) Validate() error {
 	}
 	return nil
 }
+
+// getStringField is a helper to safely extract string fields from a map
+func getStringField(m map[string]interface{}, key string) string {
+	if val, ok := m[key].(string); ok {
+		return val
+	}
+	return ""
+}