feat: Integrate OpenAI Responses API to enable GPT-5 features

core/index.d.ts

@@ -359,11 +359,15 @@ export interface ToolResultChatMessage {
   role: "tool";
   content: string;
   toolCallId: string;
+  /** Arbitrary per-message metadata (IDs, provider-specific info, etc.) */
+  metadata?: Record<string, unknown>;
 }
 
 export interface UserChatMessage {
   role: "user";
   content: MessageContent;
+  /** Arbitrary per-message metadata (IDs, provider-specific info, etc.) */
+  metadata?: Record<string, unknown>;
 }
 
 export interface ThinkingChatMessage {
@@ -372,6 +376,12 @@ export interface ThinkingChatMessage {
   signature?: string;
   redactedThinking?: string;
   toolCalls?: ToolCallDelta[];
+  reasoning_details?: {
+    signature?: string;
+    [key: string]: any;
+  }[];
+  /** Arbitrary per-message metadata (IDs, provider-specific info, etc.) */
+  metadata?: Record<string, unknown>;
 }
 
 /**
@@ -400,11 +410,15 @@ export interface AssistantChatMessage {
   content: MessageContent;
   toolCalls?: ToolCallDelta[];
   usage?: Usage;
+  /** Arbitrary per-message metadata (IDs, provider-specific info, etc.) */
+  metadata?: Record<string, unknown>;
 }
 
 export interface SystemChatMessage {
   role: "system";
   content: string;
+  /** Arbitrary per-message metadata (IDs, provider-specific info, etc.) */
+  metadata?: Record<string, unknown>;
 }
 
 export type ChatMessage =