feat: gate smart context tracking behind experimental setting

Added new 'smartContextTracking' experiment to gate the file context
tracking optimization. When disabled (default), the read_file tools
behave as before. When enabled, files that haven't changed and still
have content in the conversation context return a short 'unchanged'
response instead of re-reading the full content.

Changes:
- Added smartContextTracking to experimentIds in packages/types
- Added SMART_CONTEXT_TRACKING to experiments.ts
- Updated simpleReadFileTool.ts to check experiment before optimization
- Updated ReadFileTool.ts to check experiment before optimization

packages/types/src/experiment.ts

@@ -13,6 +13,7 @@ export const experimentIds = [
 	"imageGeneration",
 	"runSlashCommand",
 	"multipleNativeToolCalls",
+	"smartContextTracking",
 ] as const
 
 export const experimentIdsSchema = z.enum(experimentIds)
@@ -30,6 +31,7 @@ export const experimentsSchema = z.object({
 	imageGeneration: z.boolean().optional(),
 	runSlashCommand: z.boolean().optional(),
 	multipleNativeToolCalls: z.boolean().optional(),
+	smartContextTracking: z.boolean().optional(),
 })
 
 export type Experiments = z.infer<typeof experimentsSchema>

src/core/tools/ReadFileTool.ts

@@ -9,7 +9,12 @@ import { formatResponse } from "../prompts/responses"
 import { getModelMaxOutputTokens } from "../../shared/api"
 import { t } from "../../i18n"
 import { RecordSource } from "../context-tracking/FileContextTrackerTypes"
-import { checkFileContextStatus, getReReadNotice } from "../context-tracking/FileContextStatusChecker"
+import {
+	checkFileContextStatus,
+	getReReadNotice,
+	FileContextStatus,
+} from "../context-tracking/FileContextStatusChecker"
+import { EXPERIMENT_IDS, experiments } from "../../shared/experiments"
 import { isPathOutsideWorkspace } from "../../utils/pathUtils"
 import { getReadablePath } from "../../utils/path"
 import { countFileLines } from "../../integrations/misc/line-counter"
@@ -142,6 +147,13 @@ export class ReadFileTool extends BaseTool<"read_file"> {
 		try {
 			const filesToApprove: FileResult[] = []
 
+			// Check if smart context tracking experiment is enabled
+			const experimentState = await task.providerRef.deref()?.getState()
+			const isSmartContextTrackingEnabled = experiments.isEnabled(
+				experimentState?.experiments ?? {},
+				EXPERIMENT_IDS.SMART_CONTEXT_TRACKING,
+			)
+
 			for (const fileResult of fileResults) {
 				const relPath = fileResult.path
 				const fullPath = path.resolve(task.cwd, relPath)
@@ -191,9 +203,12 @@ export class ReadFileTool extends BaseTool<"read_file"> {
 						continue
 					}
 
-					// Check if file needs to be re-read based on context status
+					// Check if file needs to be re-read based on context status (only if experiment enabled)
 					// Skip this check for line range requests as those always need fresh content
-					if (!fileResult.lineRanges || fileResult.lineRanges.length === 0) {
+					if (
+						isSmartContextTrackingEnabled &&
+						(!fileResult.lineRanges || fileResult.lineRanges.length === 0)
+					) {
 						const metadata = await task.fileContextTracker.getTaskMetadata(task.taskId)
 						const contextStatus = await checkFileContextStatus(
 							relPath,

src/core/tools/simpleReadFileTool.ts

@@ -7,7 +7,12 @@ import { formatResponse } from "../prompts/responses"
 import { t } from "../../i18n"
 import { ToolUse, AskApproval, HandleError, PushToolResult, RemoveClosingTag } from "../../shared/tools"
 import { RecordSource } from "../context-tracking/FileContextTrackerTypes"
-import { checkFileContextStatus, getReReadNotice } from "../context-tracking/FileContextStatusChecker"
+import {
+	checkFileContextStatus,
+	getReReadNotice,
+	FileContextStatus,
+} from "../context-tracking/FileContextStatusChecker"
+import { EXPERIMENT_IDS, experiments } from "../../shared/experiments"
 import { isPathOutsideWorkspace } from "../../utils/pathUtils"
 import { getReadablePath } from "../../utils/path"
 import { countFileLines } from "../../integrations/misc/line-counter"
@@ -86,15 +91,30 @@ export async function simpleReadFileTool(
 			return
 		}
 
-		// Check if file needs to be re-read based on context status
-		const metadata = await cline.fileContextTracker.getTaskMetadata(cline.taskId)
-		const contextStatus = await checkFileContextStatus(relPath, fullPath, metadata, cline.apiConversationHistory)
+		// Check if smart context tracking experiment is enabled
+		const state = await cline.providerRef.deref()?.getState()
+		const isSmartContextTrackingEnabled = experiments.isEnabled(
+			state?.experiments ?? {},
+			EXPERIMENT_IDS.SMART_CONTEXT_TRACKING,
+		)
 
-		// If we need to re-read, get the notice explaining why (for later use)
-		const reReadNotice = getReReadNotice(contextStatus.reason)
+		// Check if file needs to be re-read based on context status (only if experiment enabled)
+		let contextStatus: FileContextStatus = {
+			shouldReRead: true,
+			reason: "never_read",
+		}
+		let reReadNotice: string | undefined = undefined
+
+		if (isSmartContextTrackingEnabled) {
+			const metadata = await cline.fileContextTracker.getTaskMetadata(cline.taskId)
+			contextStatus = await checkFileContextStatus(relPath, fullPath, metadata, cline.apiConversationHistory)
+
+			// If we need to re-read, get the notice explaining why (for later use)
+			reReadNotice = getReReadNotice(contextStatus.reason)
+		}
 
 		// Get max read file line setting
-		const { maxReadFileLine = -1 } = (await cline.providerRef.deref()?.getState()) ?? {}
+		const { maxReadFileLine = -1 } = state ?? {}
 
 		// Create approval message
 		const isOutsideWorkspace = isPathOutsideWorkspace(fullPath)

src/shared/__tests__/experiments.spec.ts

@@ -32,6 +32,7 @@ describe("experiments", () => {
 				imageGeneration: false,
 				runSlashCommand: false,
 				multipleNativeToolCalls: false,
+				smartContextTracking: false,
 			}
 			expect(Experiments.isEnabled(experiments, EXPERIMENT_IDS.POWER_STEERING)).toBe(false)
 		})
@@ -44,6 +45,7 @@ describe("experiments", () => {
 				imageGeneration: false,
 				runSlashCommand: false,
 				multipleNativeToolCalls: false,
+				smartContextTracking: false,
 			}
 			expect(Experiments.isEnabled(experiments, EXPERIMENT_IDS.POWER_STEERING)).toBe(true)
 		})
@@ -56,6 +58,7 @@ describe("experiments", () => {
 				imageGeneration: false,
 				runSlashCommand: false,
 				multipleNativeToolCalls: false,
+				smartContextTracking: false,
 			}
 			expect(Experiments.isEnabled(experiments, EXPERIMENT_IDS.POWER_STEERING)).toBe(false)
 		})

src/shared/experiments.ts

@@ -7,6 +7,7 @@ export const EXPERIMENT_IDS = {
 	IMAGE_GENERATION: "imageGeneration",
 	RUN_SLASH_COMMAND: "runSlashCommand",
 	MULTIPLE_NATIVE_TOOL_CALLS: "multipleNativeToolCalls",
+	SMART_CONTEXT_TRACKING: "smartContextTracking",
 } as const satisfies Record<string, ExperimentId>
 
 type _AssertExperimentIds = AssertEqual<Equals<ExperimentId, Values<typeof EXPERIMENT_IDS>>>
@@ -24,6 +25,7 @@ export const experimentConfigsMap: Record<ExperimentKey, ExperimentConfig> = {
 	IMAGE_GENERATION: { enabled: false },
 	RUN_SLASH_COMMAND: { enabled: false },
 	MULTIPLE_NATIVE_TOOL_CALLS: { enabled: false },
+	SMART_CONTEXT_TRACKING: { enabled: false },
 }
 
 export const experimentDefault = Object.fromEntries(