fix: improve reasoning_details accumulation and serialization

src/api/providers/roo.ts

@@ -179,7 +179,10 @@ export class RooHandler extends BaseOpenAiCompatibleProvider<string> {
 					if (deltaWithReasoning.reasoning_details && Array.isArray(deltaWithReasoning.reasoning_details)) {
 						for (const detail of deltaWithReasoning.reasoning_details) {
 							const index = detail.index ?? 0
-							const key = `${detail.type}-${index}`
+							// Use id as key when available to merge chunks that share the same reasoning block id
+							// This ensures that reasoning.summary and reasoning.encrypted chunks with the same id
+							// are merged into a single object, matching the provider's expected format
+							const key = detail.id ?? `${detail.type}-${index}`
 							const existing = reasoningDetailsAccumulator.get(key)
 
 							if (existing) {
@@ -194,6 +197,8 @@ export class RooHandler extends BaseOpenAiCompatibleProvider<string> {
 									existing.data = (existing.data || "") + detail.data
 								}
 								// Update other fields if provided
+								// Note: Don't update type - keep original type (e.g., reasoning.summary)
+								// even when encrypted data chunks arrive with type reasoning.encrypted
 								if (detail.id !== undefined) existing.id = detail.id
 								if (detail.format !== undefined) existing.format = detail.format
 								if (detail.signature !== undefined) existing.signature = detail.signature

src/api/transform/openai-format.ts

@@ -150,16 +150,28 @@ export function convertToOpenAiMessages(
 
 				// Check if the message has reasoning_details (used by Gemini 3, etc.)
 				const messageWithDetails = anthropicMessage as any
-				const baseMessage: OpenAI.Chat.ChatCompletionAssistantMessageParam = {
+
+				// Build message with reasoning_details BEFORE tool_calls to preserve
+				// the order expected by providers like Roo. Property order matters
+				// when sending messages back to some APIs.
+				const baseMessage: OpenAI.Chat.ChatCompletionAssistantMessageParam & { reasoning_details?: any[] } = {
 					role: "assistant",
 					content,
-					// Cannot be an empty array. API expects an array with minimum length 1, and will respond with an error if it's empty
-					tool_calls: tool_calls.length > 0 ? tool_calls : undefined,
 				}
 
-				// Preserve reasoning_details if present (will be processed by provider if needed)
+				// Add reasoning_details first (before tool_calls) to preserve provider-expected order
+				// Strip the id field from each reasoning detail as it's only used internally for accumulation
 				if (messageWithDetails.reasoning_details && Array.isArray(messageWithDetails.reasoning_details)) {
-					;(baseMessage as any).reasoning_details = messageWithDetails.reasoning_details
+					baseMessage.reasoning_details = messageWithDetails.reasoning_details.map((detail: any) => {
+						const { id, ...rest } = detail
+						return rest
+					})
+				}
+
+				// Add tool_calls after reasoning_details
+				// Cannot be an empty array. API expects an array with minimum length 1, and will respond with an error if it's empty
+				if (tool_calls.length > 0) {
+					baseMessage.tool_calls = tool_calls
 				}
 
 				openAiMessages.push(baseMessage)