feat: add preserveReasoning flag to include reasoning in API history (#8934)

packages/types/src/model.ts

@@ -68,6 +68,7 @@ export const modelInfoSchema = z.object({
 	requiredReasoningBudget: z.boolean().optional(),
 	supportsReasoningEffort: z.boolean().optional(),
 	requiredReasoningEffort: z.boolean().optional(),
+	preserveReasoning: z.boolean().optional(),
 	supportedParameters: z.array(modelParametersSchema).optional(),
 	inputPrice: z.number().optional(),
 	outputPrice: z.number().optional(),

packages/types/src/providers/minimax.ts

@@ -16,6 +16,7 @@ export const minimaxModels = {
 		outputPrice: 1.2,
 		cacheWritesPrice: 0,
 		cacheReadsPrice: 0,
+		preserveReasoning: true,
 		description:
 			"MiniMax M2, a model born for Agents and code, featuring Top-tier Coding Capabilities, Powerful Agentic Performance, and Ultimate Cost-Effectiveness & Speed.",
 	},

src/core/task/Task.ts

@@ -2373,9 +2373,16 @@ export class Task extends EventEmitter<TaskEvents> implements TaskLike {
 						})
 					}
 
+					// Check if we should preserve reasoning in the assistant message
+					let finalAssistantMessage = assistantMessage
+					if (reasoningMessage && this.api.getModel().info.preserveReasoning) {
+						// Prepend reasoning in XML tags to the assistant message so it's included in API history
+						finalAssistantMessage = `<think>${reasoningMessage}</think>\n${assistantMessage}`
+					}
+
 					await this.addToApiConversationHistory({
 						role: "assistant",
-						content: [{ type: "text", text: assistantMessage }],
+						content: [{ type: "text", text: finalAssistantMessage }],
 					})
 
 					TelemetryService.instance.captureConversationMessage(this.taskId, "assistant")

src/core/task/__tests__/reasoning-preservation.test.ts

@@ -0,0 +1,328 @@
+import { describe, it, expect, vi, beforeEach, beforeAll } from "vitest"
+import type { ClineProvider } from "../../webview/ClineProvider"
+import type { ProviderSettings, ModelInfo } from "@roo-code/types"
+
+// Mock vscode module before importing Task
+vi.mock("vscode", () => ({
+	workspace: {
+		createFileSystemWatcher: vi.fn(() => ({
+			onDidCreate: vi.fn(),
+			onDidChange: vi.fn(),
+			onDidDelete: vi.fn(),
+			dispose: vi.fn(),
+		})),
+		getConfiguration: vi.fn(() => ({
+			get: vi.fn(() => true),
+		})),
+		openTextDocument: vi.fn(),
+		applyEdit: vi.fn(),
+	},
+	RelativePattern: vi.fn((base, pattern) => ({ base, pattern })),
+	window: {
+		createOutputChannel: vi.fn(() => ({
+			appendLine: vi.fn(),
+			dispose: vi.fn(),
+		})),
+		createTextEditorDecorationType: vi.fn(() => ({
+			dispose: vi.fn(),
+		})),
+		showTextDocument: vi.fn(),
+		activeTextEditor: undefined,
+	},
+	Uri: {
+		file: vi.fn((path) => ({ fsPath: path })),
+		parse: vi.fn((str) => ({ toString: () => str })),
+	},
+	Range: vi.fn(),
+	Position: vi.fn(),
+	WorkspaceEdit: vi.fn(() => ({
+		replace: vi.fn(),
+		insert: vi.fn(),
+		delete: vi.fn(),
+	})),
+	ViewColumn: {
+		One: 1,
+		Two: 2,
+		Three: 3,
+	},
+}))
+
+// Mock other dependencies
+vi.mock("../../services/mcp/McpServerManager", () => ({
+	McpServerManager: {
+		getInstance: vi.fn().mockResolvedValue(null),
+	},
+}))
+
+vi.mock("../../integrations/terminal/TerminalRegistry", () => ({
+	TerminalRegistry: {
+		releaseTerminalsForTask: vi.fn(),
+	},
+}))
+
+vi.mock("@roo-code/telemetry", () => ({
+	TelemetryService: {
+		instance: {
+			captureTaskCreated: vi.fn(),
+			captureTaskRestarted: vi.fn(),
+			captureConversationMessage: vi.fn(),
+			captureLlmCompletion: vi.fn(),
+			captureConsecutiveMistakeError: vi.fn(),
+		},
+	},
+}))
+
+describe("Task reasoning preservation", () => {
+	let mockProvider: Partial<ClineProvider>
+	let mockApiConfiguration: ProviderSettings
+	let Task: any
+
+	beforeAll(async () => {
+		// Import Task after mocks are set up
+		const taskModule = await import("../Task")
+		Task = taskModule.Task
+	})
+
+	beforeEach(() => {
+		// Mock provider with necessary methods
+		mockProvider = {
+			postStateToWebview: vi.fn().mockResolvedValue(undefined),
+			getState: vi.fn().mockResolvedValue({
+				mode: "code",
+				experiments: {},
+			}),
+			context: {
+				globalStorageUri: { fsPath: "/test/storage" },
+				extensionPath: "/test/extension",
+			} as any,
+			log: vi.fn(),
+			updateTaskHistory: vi.fn().mockResolvedValue(undefined),
+			postMessageToWebview: vi.fn().mockResolvedValue(undefined),
+		}
+
+		mockApiConfiguration = {
+			apiProvider: "anthropic",
+			apiKey: "test-key",
+		} as ProviderSettings
+	})
+
+	it("should append reasoning to assistant message when preserveReasoning is true", async () => {
+		// Create a task instance
+		const task = new Task({
+			provider: mockProvider as ClineProvider,
+			apiConfiguration: mockApiConfiguration,
+			task: "Test task",
+			startTask: false,
+		})
+
+		// Mock the API to return a model with preserveReasoning enabled
+		const mockModelInfo: ModelInfo = {
+			contextWindow: 16000,
+			supportsPromptCache: true,
+			preserveReasoning: true,
+		}
+
+		task.api = {
+			getModel: vi.fn().mockReturnValue({
+				id: "test-model",
+				info: mockModelInfo,
+			}),
+		}
+
+		// Mock the API conversation history
+		task.apiConversationHistory = []
+
+		// Simulate adding an assistant message with reasoning
+		const assistantMessage = "Here is my response to your question."
+		const reasoningMessage = "Let me think about this step by step. First, I need to..."
+
+		// Spy on addToApiConversationHistory
+		const addToApiHistorySpy = vi.spyOn(task as any, "addToApiConversationHistory")
+
+		// Simulate what happens in the streaming loop when preserveReasoning is true
+		let finalAssistantMessage = assistantMessage
+		if (reasoningMessage && task.api.getModel().info.preserveReasoning) {
+			finalAssistantMessage = `<think>${reasoningMessage}</think>\n${assistantMessage}`
+		}
+
+		await (task as any).addToApiConversationHistory({
+			role: "assistant",
+			content: [{ type: "text", text: finalAssistantMessage }],
+		})
+
+		// Verify that reasoning was prepended in <think> tags to the assistant message
+		expect(addToApiHistorySpy).toHaveBeenCalledWith({
+			role: "assistant",
+			content: [
+				{
+					type: "text",
+					text: "<think>Let me think about this step by step. First, I need to...</think>\nHere is my response to your question.",
+				},
+			],
+		})
+
+		// Verify the API conversation history contains the message with reasoning
+		expect(task.apiConversationHistory).toHaveLength(1)
+		expect(task.apiConversationHistory[0].content[0].text).toContain("<think>")
+		expect(task.apiConversationHistory[0].content[0].text).toContain("</think>")
+		expect(task.apiConversationHistory[0].content[0].text).toContain("Here is my response to your question.")
+		expect(task.apiConversationHistory[0].content[0].text).toContain(
+			"Let me think about this step by step. First, I need to...",
+		)
+	})
+
+	it("should NOT append reasoning to assistant message when preserveReasoning is false", async () => {
+		// Create a task instance
+		const task = new Task({
+			provider: mockProvider as ClineProvider,
+			apiConfiguration: mockApiConfiguration,
+			task: "Test task",
+			startTask: false,
+		})
+
+		// Mock the API to return a model with preserveReasoning disabled (or undefined)
+		const mockModelInfo: ModelInfo = {
+			contextWindow: 16000,
+			supportsPromptCache: true,
+			preserveReasoning: false,
+		}
+
+		task.api = {
+			getModel: vi.fn().mockReturnValue({
+				id: "test-model",
+				info: mockModelInfo,
+			}),
+		}
+
+		// Mock the API conversation history
+		task.apiConversationHistory = []
+
+		// Simulate adding an assistant message with reasoning
+		const assistantMessage = "Here is my response to your question."
+		const reasoningMessage = "Let me think about this step by step. First, I need to..."
+
+		// Spy on addToApiConversationHistory
+		const addToApiHistorySpy = vi.spyOn(task as any, "addToApiConversationHistory")
+
+		// Simulate what happens in the streaming loop when preserveReasoning is false
+		let finalAssistantMessage = assistantMessage
+		if (reasoningMessage && task.api.getModel().info.preserveReasoning) {
+			finalAssistantMessage = `<think>${reasoningMessage}</think>\n${assistantMessage}`
+		}
+
+		await (task as any).addToApiConversationHistory({
+			role: "assistant",
+			content: [{ type: "text", text: finalAssistantMessage }],
+		})
+
+		// Verify that reasoning was NOT appended to the assistant message
+		expect(addToApiHistorySpy).toHaveBeenCalledWith({
+			role: "assistant",
+			content: [{ type: "text", text: "Here is my response to your question." }],
+		})
+
+		// Verify the API conversation history does NOT contain reasoning
+		expect(task.apiConversationHistory).toHaveLength(1)
+		expect(task.apiConversationHistory[0].content[0].text).toBe("Here is my response to your question.")
+		expect(task.apiConversationHistory[0].content[0].text).not.toContain("<think>")
+	})
+
+	it("should handle empty reasoning message gracefully when preserveReasoning is true", async () => {
+		// Create a task instance
+		const task = new Task({
+			provider: mockProvider as ClineProvider,
+			apiConfiguration: mockApiConfiguration,
+			task: "Test task",
+			startTask: false,
+		})
+
+		// Mock the API to return a model with preserveReasoning enabled
+		const mockModelInfo: ModelInfo = {
+			contextWindow: 16000,
+			supportsPromptCache: true,
+			preserveReasoning: true,
+		}
+
+		task.api = {
+			getModel: vi.fn().mockReturnValue({
+				id: "test-model",
+				info: mockModelInfo,
+			}),
+		}
+
+		// Mock the API conversation history
+		task.apiConversationHistory = []
+
+		const assistantMessage = "Here is my response."
+		const reasoningMessage = "" // Empty reasoning
+
+		// Spy on addToApiConversationHistory
+		const addToApiHistorySpy = vi.spyOn(task as any, "addToApiConversationHistory")
+
+		// Simulate what happens in the streaming loop
+		let finalAssistantMessage = assistantMessage
+		if (reasoningMessage && task.api.getModel().info.preserveReasoning) {
+			finalAssistantMessage = `<think>${reasoningMessage}</think>\n${assistantMessage}`
+		}
+
+		await (task as any).addToApiConversationHistory({
+			role: "assistant",
+			content: [{ type: "text", text: finalAssistantMessage }],
+		})
+
+		// Verify that no reasoning tags were added when reasoning is empty
+		expect(addToApiHistorySpy).toHaveBeenCalledWith({
+			role: "assistant",
+			content: [{ type: "text", text: "Here is my response." }],
+		})
+
+		// Verify the message doesn't contain reasoning tags
+		expect(task.apiConversationHistory[0].content[0].text).toBe("Here is my response.")
+		expect(task.apiConversationHistory[0].content[0].text).not.toContain("<think>")
+	})
+
+	it("should handle undefined preserveReasoning (defaults to false)", async () => {
+		// Create a task instance
+		const task = new Task({
+			provider: mockProvider as ClineProvider,
+			apiConfiguration: mockApiConfiguration,
+			task: "Test task",
+			startTask: false,
+		})
+
+		// Mock the API to return a model without preserveReasoning field (undefined)
+		const mockModelInfo: ModelInfo = {
+			contextWindow: 16000,
+			supportsPromptCache: true,
+			// preserveReasoning is undefined
+		}
+
+		task.api = {
+			getModel: vi.fn().mockReturnValue({
+				id: "test-model",
+				info: mockModelInfo,
+			}),
+		}
+
+		// Mock the API conversation history
+		task.apiConversationHistory = []
+
+		const assistantMessage = "Here is my response."
+		const reasoningMessage = "Some reasoning here."
+
+		// Simulate what happens in the streaming loop
+		let finalAssistantMessage = assistantMessage
+		if (reasoningMessage && task.api.getModel().info.preserveReasoning) {
+			finalAssistantMessage = `<think>${reasoningMessage}</think>\n${assistantMessage}`
+		}
+
+		await (task as any).addToApiConversationHistory({
+			role: "assistant",
+			content: [{ type: "text", text: finalAssistantMessage }],
+		})
+
+		// Verify reasoning was NOT prepended (undefined defaults to false)
+		expect(task.apiConversationHistory[0].content[0].text).toBe("Here is my response.")
+		expect(task.apiConversationHistory[0].content[0].text).not.toContain("<think>")
+	})
+})