fix: prevent context truncation when condensing is disabled (threshold=100%)

- Modified truncateConversationIfNeeded to skip summarization when threshold is 100%
- Prevent sliding window truncation when condensing is explicitly disabled
- Added test to verify no truncation occurs when threshold is 100%
- Updated existing tests to use appropriate thresholds

Fixes #7811

src/core/sliding-window/__tests__/sliding-window.spec.ts

@@ -577,7 +577,7 @@ describe("Sliding Window", () => {
 				maxTokens: modelInfo.maxTokens,
 				apiHandler: mockApiHandler,
 				autoCondenseContext: true,
-				autoCondenseContextPercent: 100,
+				autoCondenseContextPercent: 50, // Use a threshold less than 100%
 				systemPrompt: "System prompt",
 				taskId,
 				profileThresholds: {},
@@ -644,7 +644,7 @@ describe("Sliding Window", () => {
 				maxTokens: modelInfo.maxTokens,
 				apiHandler: mockApiHandler,
 				autoCondenseContext: true,
-				autoCondenseContextPercent: 100,
+				autoCondenseContextPercent: 50, // Use a threshold less than 100%
 				systemPrompt: "System prompt",
 				taskId,
 				profileThresholds: {},
@@ -821,6 +821,48 @@ describe("Sliding Window", () => {
 			// Clean up
 			summarizeSpy.mockRestore()
 		})
+
+		it("should not truncate when autoCondenseContext is true and threshold is 100% even if tokens exceed allowedTokens", async () => {
+			const modelInfo = createModelInfo(100000, 30000)
+			const totalTokens = 75000 // This exceeds allowedTokens (60000) but should not truncate when disabled
+
+			const messagesWithSmallContent = [
+				...messages.slice(0, -1),
+				{ ...messages[messages.length - 1], content: "" },
+			]
+
+			// Spy on summarizeConversation to ensure it's not called
+			const summarizeSpy = vi.spyOn(condenseModule, "summarizeConversation")
+
+			const result = await truncateConversationIfNeeded({
+				messages: messagesWithSmallContent,
+				totalTokens,
+				contextWindow: modelInfo.contextWindow,
+				maxTokens: modelInfo.maxTokens,
+				apiHandler: mockApiHandler,
+				autoCondenseContext: true, // Enabled but with 100% threshold
+				autoCondenseContextPercent: 100, // 100% threshold means never condense
+				systemPrompt: "System prompt",
+				taskId,
+				profileThresholds: {},
+				currentProfileId: "default",
+			})
+
+			// Verify summarizeConversation was NOT called when threshold is 100%
+			expect(summarizeSpy).not.toHaveBeenCalled()
+
+			// Should NOT truncate even though tokens exceed allowedTokens when threshold is 100%
+			expect(result).toEqual({
+				messages: messagesWithSmallContent,
+				summary: "",
+				cost: 0,
+				prevContextTokens: totalTokens,
+				error: undefined,
+			})
+
+			// Clean up
+			summarizeSpy.mockRestore()
+		})
 	})
 
 	/**

src/core/sliding-window/index.ts

@@ -142,7 +142,7 @@ export async function truncateConversationIfNeeded({
 	}
 	// If no specific threshold is found for the profile, fall back to global setting
 
-	if (autoCondenseContext) {
+	if (autoCondenseContext && effectiveThreshold < 100) {
 		const contextPercent = (100 * prevContextTokens) / contextWindow
 		if (contextPercent >= effectiveThreshold || prevContextTokens > allowedTokens) {
 			// Attempt to intelligently condense the context
@@ -166,7 +166,15 @@ export async function truncateConversationIfNeeded({
 	}
 
 	// Fall back to sliding window truncation if needed
+	// Exception: When context condensing is explicitly disabled (threshold = 100%), don't truncate
 	if (prevContextTokens > allowedTokens) {
+		// Check if condensing is explicitly disabled (threshold is 100% and autoCondenseContext is true)
+		// This means the user has set the threshold to 100% to disable condensing
+		if (autoCondenseContext && effectiveThreshold >= 100) {
+			// Context condensing is explicitly disabled by user, don't truncate
+			return { messages, summary: "", cost, prevContextTokens, error }
+		}
+		// Apply sliding window truncation in all other cases
 		const truncatedMessages = truncateConversation(messages, 0.5, taskId)
 		return { messages: truncatedMessages, prevContextTokens, summary: "", cost, error }
 	}