fix: correct context token calculation to only include input tokens

- Fixed contextTokens calculation in getApiMetrics to only count tokensIn
- Previously it was incorrectly summing tokensIn + tokensOut + cacheWrites + cacheReads
- This was causing premature context condensing as the context size was inflated
- Updated tests to reflect the correct behavior
- Added proper type checking to handle non-numeric token values

Fixes #6668

Author: roomote

src/shared/__tests__/getApiMetrics.spec.ts

@@ -61,7 +61,7 @@ describe("getApiMetrics", () => {
 			expect(result.totalCacheWrites).toBe(5)
 			expect(result.totalCacheReads).toBe(10)
 			expect(result.totalCost).toBe(0.005)
-			expect(result.contextTokens).toBe(300) // 100 + 200 (OpenAI default, no cache tokens)
+			expect(result.contextTokens).toBe(100) // Only input tokens
 		})
 
 		it("should calculate metrics from multiple api_req_started messages", () => {
@@ -83,7 +83,7 @@ describe("getApiMetrics", () => {
 			expect(result.totalCacheWrites).toBe(8) // 5 + 3
 			expect(result.totalCacheReads).toBe(17) // 10 + 7
 			expect(result.totalCost).toBe(0.008) // 0.005 + 0.003
-			expect(result.contextTokens).toBe(200) // 50 + 150 (OpenAI default, no cache tokens)
+			expect(result.contextTokens).toBe(50) // Only input tokens from last request
 		})
 
 		it("should calculate metrics from condense_context messages", () => {
@@ -123,7 +123,7 @@ describe("getApiMetrics", () => {
 			expect(result.totalCacheWrites).toBe(8) // 5 + 3
 			expect(result.totalCacheReads).toBe(17) // 10 + 7
 			expect(result.totalCost).toBe(0.01) // 0.005 + 0.002 + 0.003
-			expect(result.contextTokens).toBe(200) // 50 + 150 (OpenAI default, no cache tokens)
+			expect(result.contextTokens).toBe(50) // Only input tokens from last request
 		})
 	})
 
@@ -243,8 +243,8 @@ describe("getApiMetrics", () => {
 			expect(result.totalCost).toBe(0.005)
 
 			// The implementation will use the last message that has any tokens
-			// In this case, it's the message with tokensOut:200 (since the last few messages have no tokensIn/Out)
-			expect(result.contextTokens).toBe(200) // 0 + 200 (from the tokensOut message)
+			// In this case, the last message with tokensIn is the first one with tokensIn:100
+			expect(result.contextTokens).toBe(100) // Only tokensIn from the first message
 		})
 
 		it("should handle non-number values in api_req_started message", () => {
@@ -264,8 +264,8 @@ describe("getApiMetrics", () => {
 			expect(result.totalCacheReads).toBeUndefined()
 			expect(result.totalCost).toBe(0)
 
-			// The implementation concatenates all token values including cache tokens
-			expect(result.contextTokens).toBe("not-a-numbernot-a-number") // tokensIn + tokensOut (OpenAI default)
+			// The implementation should only use tokensIn
+			expect(result.contextTokens).toBe(0) // tokensIn is "not-a-number" which evaluates to 0
 		})
 	})
 
@@ -278,8 +278,8 @@ describe("getApiMetrics", () => {
 
 			const result = getApiMetrics(messages)
 
-			// Should use the values from the last api_req_started message
-			expect(result.contextTokens).toBe(200) // 50 + 150 (OpenAI default, no cache tokens)
+			// Should use the tokensIn from the last api_req_started message
+			expect(result.contextTokens).toBe(50) // Only tokensIn
 		})
 
 		it("should calculate contextTokens from the last condense_context message", () => {
@@ -304,8 +304,8 @@ describe("getApiMetrics", () => {
 
 			const result = getApiMetrics(messages)
 
-			// Should use the values from the last api_req_started message
-			expect(result.contextTokens).toBe(200) // 50 + 150 (OpenAI default, no cache tokens)
+			// Should use the tokensIn from the last api_req_started message
+			expect(result.contextTokens).toBe(50) // Only tokensIn
 		})
 
 		it("should handle missing values when calculating contextTokens", () => {
@@ -320,7 +320,7 @@ describe("getApiMetrics", () => {
 			const result = getApiMetrics(messages)
 
 			// Should handle missing or invalid values
-			expect(result.contextTokens).toBe(0) // 0 + 0 (OpenAI default, no cache tokens)
+			expect(result.contextTokens).toBe(0) // tokensIn is null, defaults to 0
 
 			// Restore console.error
 			console.error = originalConsoleError

src/shared/getApiMetrics.ts

@@ -76,12 +76,9 @@ export function getApiMetrics(messages: ClineMessage[]) {
 				const { tokensIn, tokensOut, cacheWrites, cacheReads, apiProtocol } = parsedText
 
 				// Calculate context tokens based on API protocol
-				if (apiProtocol === "anthropic") {
-					result.contextTokens = (tokensIn || 0) + (tokensOut || 0) + (cacheWrites || 0) + (cacheReads || 0)
-				} else {
-					// For OpenAI (or when protocol is not specified)
-					result.contextTokens = (tokensIn || 0) + (tokensOut || 0)
-				}
+				// Context tokens should only include input tokens (the actual context size)
+				// Output tokens, cache writes, and cache reads are not part of the context
+				result.contextTokens = typeof tokensIn === "number" ? tokensIn : 0
 			} catch (error) {
 				console.error("Error parsing JSON:", error)
 				continue