feat: implement experimental features system

- Add experiments.ts to manage experimental features
- Refactor experimental diff strategy into experiments system
- Add UI components for managing experimental features
- Add tests for experimental tools
- Update system prompts to handle experiments

src/core/Cline.ts

@@ -61,6 +61,7 @@ import { OpenRouterHandler } from "../api/providers/openrouter"
 import { McpHub } from "../services/mcp/McpHub"
 import crypto from "crypto"
 import { insertGroups } from "./diff/insert-groups"
+import { EXPERIMENT_IDS } from "../shared/experiments"
 
 const cwd =
 	vscode.workspace.workspaceFolders?.map((folder) => folder.uri.fsPath).at(0) ?? path.join(os.homedir(), "Desktop") // may or may not exist but fs checking existence would immediately ask for permission which would be bad UX, need to come up with a better solution
@@ -151,9 +152,8 @@ export class Cline {
 	async updateDiffStrategy(experimentalDiffStrategy?: boolean) {
 		// If not provided, get from current state
 		if (experimentalDiffStrategy === undefined) {
-			const { experimentalDiffStrategy: stateExperimentalDiffStrategy } =
-				(await this.providerRef.deref()?.getState()) ?? {}
-			experimentalDiffStrategy = stateExperimentalDiffStrategy ?? false
+			const { experiments: stateExperimental } = (await this.providerRef.deref()?.getState()) ?? {}
+			experimentalDiffStrategy = stateExperimental?.[EXPERIMENT_IDS.DIFF_STRATEGY] ?? false
 		}
 		this.diffStrategy = getDiffStrategy(this.api.getModel().id, this.fuzzyMatchThreshold, experimentalDiffStrategy)
 	}
@@ -810,7 +810,7 @@ export class Cline {
 			})
 		}
 
-		const { browserViewportSize, mode, customModePrompts, preferredLanguage } =
+		const { browserViewportSize, mode, customModePrompts, preferredLanguage, experiments } =
 			(await this.providerRef.deref()?.getState()) ?? {}
 		const { customModes } = (await this.providerRef.deref()?.getState()) ?? {}
 		const systemPrompt = await (async () => {
@@ -831,6 +831,7 @@ export class Cline {
 				this.customInstructions,
 				preferredLanguage,
 				this.diffEnabled,
+				experiments,
 			)
 		})()
 

src/core/prompts/__tests__/system.test.ts

@@ -11,6 +11,7 @@ import { defaultModeSlug, modes } from "../../../shared/modes"
 import "../../../utils/path"
 import { addCustomInstructions } from "../sections/custom-instructions"
 import * as modesSection from "../sections/modes"
+import { EXPERIMENT_IDS } from "../../../shared/experiments"
 
 // Mock the sections
 jest.mock("../sections/modes", () => ({
@@ -121,6 +122,7 @@ const createMockMcpHub = (): McpHub =>
 
 describe("SYSTEM_PROMPT", () => {
 	let mockMcpHub: McpHub
+	let experiments: Record<string, boolean>
 
 	beforeAll(() => {
 		// Ensure fs mock is properly initialized
@@ -140,6 +142,10 @@ describe("SYSTEM_PROMPT", () => {
 			"/mock/mcp/path",
 		]
 		dirs.forEach((dir) => mockFs._mockDirectories.add(dir))
+		experiments = {
+			[EXPERIMENT_IDS.SEARCH_AND_REPLACE]: false,
+			[EXPERIMENT_IDS.INSERT_BLOCK]: false,
+		}
 	})
 
 	beforeEach(() => {
@@ -164,6 +170,10 @@ describe("SYSTEM_PROMPT", () => {
 			defaultModeSlug, // mode
 			undefined, // customModePrompts
 			undefined, // customModes
+			undefined, // globalCustomInstructions
+			undefined, // preferredLanguage
+			undefined, // diffEnabled
+			experiments,
 		)
 
 		expect(prompt).toMatchSnapshot()
@@ -179,7 +189,11 @@ describe("SYSTEM_PROMPT", () => {
 			"1280x800", // browserViewportSize
 			defaultModeSlug, // mode
 			undefined, // customModePrompts
-			undefined, // customModes
+			undefined, // customModes,
+			undefined, // globalCustomInstructions
+			undefined, // preferredLanguage
+			undefined, // diffEnabled
+			experiments,
 		)
 
 		expect(prompt).toMatchSnapshot()
@@ -197,7 +211,11 @@ describe("SYSTEM_PROMPT", () => {
 			undefined, // browserViewportSize
 			defaultModeSlug, // mode
 			undefined, // customModePrompts
-			undefined, // customModes
+			undefined, // customModes,
+			undefined, // globalCustomInstructions
+			undefined, // preferredLanguage
+			undefined, // diffEnabled
+			experiments,
 		)
 
 		expect(prompt).toMatchSnapshot()
@@ -213,7 +231,11 @@ describe("SYSTEM_PROMPT", () => {
 			undefined, // browserViewportSize
 			defaultModeSlug, // mode
 			undefined, // customModePrompts
-			undefined, // customModes
+			undefined, // customModes,
+			undefined, // globalCustomInstructions
+			undefined, // preferredLanguage
+			undefined, // diffEnabled
+			experiments,
 		)
 
 		expect(prompt).toMatchSnapshot()
@@ -229,7 +251,11 @@ describe("SYSTEM_PROMPT", () => {
 			"900x600", // different viewport size
 			defaultModeSlug, // mode
 			undefined, // customModePrompts
-			undefined, // customModes
+			undefined, // customModes,
+			undefined, // globalCustomInstructions
+			undefined, // preferredLanguage
+			undefined, // diffEnabled
+			experiments,
 		)
 
 		expect(prompt).toMatchSnapshot()
@@ -249,6 +275,7 @@ describe("SYSTEM_PROMPT", () => {
 			undefined, // globalCustomInstructions
 			undefined, // preferredLanguage
 			true, // diffEnabled
+			experiments,
 		)
 
 		expect(prompt).toContain("apply_diff")
@@ -269,6 +296,7 @@ describe("SYSTEM_PROMPT", () => {
 			undefined, // globalCustomInstructions
 			undefined, // preferredLanguage
 			false, // diffEnabled
+			experiments,
 		)
 
 		expect(prompt).not.toContain("apply_diff")
@@ -289,6 +317,7 @@ describe("SYSTEM_PROMPT", () => {
 			undefined, // globalCustomInstructions
 			undefined, // preferredLanguage
 			undefined, // diffEnabled
+			experiments,
 		)
 
 		expect(prompt).not.toContain("apply_diff")
@@ -308,6 +337,8 @@ describe("SYSTEM_PROMPT", () => {
 			undefined, // customModes
 			undefined, // globalCustomInstructions
 			"Spanish", // preferredLanguage
+			undefined, // diffEnabled
+			experiments,
 		)
 
 		expect(prompt).toContain("Language Preference:")
@@ -337,6 +368,9 @@ describe("SYSTEM_PROMPT", () => {
 			undefined, // customModePrompts
 			customModes, // customModes
 			"Global instructions", // globalCustomInstructions
+			undefined, // preferredLanguage
+			undefined, // diffEnabled
+			experiments,
 		)
 
 		// Role definition should be at the top
@@ -368,6 +402,10 @@ describe("SYSTEM_PROMPT", () => {
 			defaultModeSlug,
 			customModePrompts,
 			undefined,
+			undefined,
+			undefined,
+			undefined,
+			experiments,
 		)
 
 		// Role definition from promptComponent should be at the top
@@ -394,18 +432,101 @@ describe("SYSTEM_PROMPT", () => {
 			defaultModeSlug,
 			customModePrompts,
 			undefined,
+			undefined,
+			undefined,
+			undefined,
+			experiments,
 		)
 
 		// Should use the default mode's role definition
 		expect(prompt.indexOf(modes[0].roleDefinition)).toBeLessThan(prompt.indexOf("TOOL USE"))
 	})
 
+	describe("experimental tools", () => {
+		it("should disable experimental tools by default", async () => {
+			const prompt = await SYSTEM_PROMPT(
+				mockContext,
+				"/test/path",
+				false, // supportsComputerUse
+				undefined, // mcpHub
+				undefined, // diffStrategy
+				undefined, // browserViewportSize
+				defaultModeSlug, // mode
+				undefined, // customModePrompts
+				undefined, // customModes
+				undefined, // globalCustomInstructions
+				undefined, // preferredLanguage
+				undefined, // diffEnabled
+				experiments, // experiments - undefined should disable all experimental tools
+			)
+
+			// Verify experimental tools are not included in the prompt
+			expect(prompt).not.toContain(EXPERIMENT_IDS.SEARCH_AND_REPLACE)
+			expect(prompt).not.toContain(EXPERIMENT_IDS.INSERT_BLOCK)
+		})
+
+		it("should enable experimental tools when explicitly enabled", async () => {
+			const experiments = {
+				[EXPERIMENT_IDS.SEARCH_AND_REPLACE]: true,
+				[EXPERIMENT_IDS.INSERT_BLOCK]: true,
+			}
+
+			const prompt = await SYSTEM_PROMPT(
+				mockContext,
+				"/test/path",
+				false, // supportsComputerUse
+				undefined, // mcpHub
+				undefined, // diffStrategy
+				undefined, // browserViewportSize
+				defaultModeSlug, // mode
+				undefined, // customModePrompts
+				undefined, // customModes
+				undefined, // globalCustomInstructions
+				undefined, // preferredLanguage
+				undefined, // diffEnabled
+				experiments,
+			)
+
+			// Verify experimental tools are included in the prompt when enabled
+			expect(prompt).toContain(EXPERIMENT_IDS.SEARCH_AND_REPLACE)
+			expect(prompt).toContain(EXPERIMENT_IDS.INSERT_BLOCK)
+		})
+
+		it("should selectively enable experimental tools", async () => {
+			const experiments = {
+				[EXPERIMENT_IDS.SEARCH_AND_REPLACE]: true,
+				[EXPERIMENT_IDS.INSERT_BLOCK]: false,
+			}
+
+			const prompt = await SYSTEM_PROMPT(
+				mockContext,
+				"/test/path",
+				false, // supportsComputerUse
+				undefined, // mcpHub
+				undefined, // diffStrategy
+				undefined, // browserViewportSize
+				defaultModeSlug, // mode
+				undefined, // customModePrompts
+				undefined, // customModes
+				undefined, // globalCustomInstructions
+				undefined, // preferredLanguage
+				undefined, // diffEnabled
+				experiments,
+			)
+
+			// Verify only enabled experimental tools are included
+			expect(prompt).toContain(EXPERIMENT_IDS.SEARCH_AND_REPLACE)
+			expect(prompt).not.toContain(EXPERIMENT_IDS.INSERT_BLOCK)
+		})
+	})
+
 	afterAll(() => {
 		jest.restoreAllMocks()
 	})
 })
 
 describe("addCustomInstructions", () => {
+	let experiments: Record<string, boolean>
 	beforeAll(() => {
 		// Ensure fs mock is properly initialized
 		const mockFs = jest.requireMock("fs/promises")
@@ -417,6 +538,11 @@ describe("addCustomInstructions", () => {
 			}
 			throw new Error(`ENOENT: no such file or directory, mkdir '${path}'`)
 		})
+
+		experiments = {
+			[EXPERIMENT_IDS.SEARCH_AND_REPLACE]: false,
+			[EXPERIMENT_IDS.INSERT_BLOCK]: false,
+		}
 	})
 
 	beforeEach(() => {
@@ -434,6 +560,10 @@ describe("addCustomInstructions", () => {
 			"architect", // mode
 			undefined, // customModePrompts
 			undefined, // customModes
+			undefined,
+			undefined,
+			undefined,
+			experiments,
 		)
 
 		expect(prompt).toMatchSnapshot()
@@ -450,6 +580,10 @@ describe("addCustomInstructions", () => {
 			"ask", // mode
 			undefined, // customModePrompts
 			undefined, // customModes
+			undefined,
+			undefined,
+			undefined,
+			experiments,
 		)
 
 		expect(prompt).toMatchSnapshot()

src/core/prompts/system.ts

@@ -39,6 +39,7 @@ async function generatePrompt(
 	globalCustomInstructions?: string,
 	preferredLanguage?: string,
 	diffEnabled?: boolean,
+	experiments?: Record<string, boolean>,
 ): Promise<string> {
 	if (!context) {
 		throw new Error("Extension context is required for generating system prompt")
@@ -68,6 +69,7 @@ ${getToolDescriptionsForMode(
 	browserViewportSize,
 	mcpHub,
 	customModeConfigs,
+	experiments,
 )}
 
 ${getToolUseGuidelinesSection()}
@@ -102,6 +104,7 @@ export const SYSTEM_PROMPT = async (
 	globalCustomInstructions?: string,
 	preferredLanguage?: string,
 	diffEnabled?: boolean,
+	experiments?: Record<string, boolean>,
 ): Promise<string> => {
 	if (!context) {
 		throw new Error("Extension context is required for generating system prompt")
@@ -135,5 +138,6 @@ export const SYSTEM_PROMPT = async (
 		globalCustomInstructions,
 		preferredLanguage,
 		diffEnabled,
+		experiments,
 	)
 }

src/core/prompts/tools/index.ts

@@ -46,6 +46,7 @@ export function getToolDescriptionsForMode(
 	browserViewportSize?: string,
 	mcpHub?: McpHub,
 	customModes?: ModeConfig[],
+	experiments?: Record<string, boolean>,
 ): string {
 	const config = getModeConfig(mode, customModes)
 	const args: ToolArgs = {
@@ -64,7 +65,7 @@ export function getToolDescriptionsForMode(
 		const toolGroup = TOOL_GROUPS[groupName]
 		if (toolGroup) {
 			toolGroup.forEach((tool) => {
-				if (isToolAllowedForMode(tool as ToolName, mode, customModes ?? [])) {
+				if (isToolAllowedForMode(tool as ToolName, mode, customModes ?? [], experiments ?? {})) {
 					tools.add(tool)
 				}
 			})

src/core/webview/ClineProvider.ts

@@ -40,6 +40,12 @@ import { singleCompletionHandler } from "../../utils/single-completion-handler"
 import { getCommitInfo, searchCommits, getWorkingState } from "../../utils/git"
 import { ConfigManager } from "../config/ConfigManager"
 import { CustomModesManager } from "../config/CustomModesManager"
+import {
+	EXPERIMENT_IDS,
+	experimentConfigs,
+	experiments as Experiments,
+	experimentDefault,
+} from "../../shared/experiments"
 import { CustomSupportPrompts, supportPrompt } from "../../shared/support-prompt"
 
 import { ACTION_NAMES } from "../CodeActionProvider"
@@ -118,7 +124,7 @@ type GlobalStateKey =
 	| "customModePrompts"
 	| "customSupportPrompts"
 	| "enhancementApiConfigId"
-	| "experimentalDiffStrategy"
+	| "experiments" // Map of experiment IDs to their enabled state
 	| "autoApprovalEnabled"
 	| "customModes" // Array of custom modes
 
@@ -339,7 +345,7 @@ export class ClineProvider implements vscode.WebviewViewProvider {
 			fuzzyMatchThreshold,
 			mode,
 			customInstructions: globalInstructions,
-			experimentalDiffStrategy,
+			experiments,
 		} = await this.getState()
 
 		const modePrompt = customModePrompts?.[mode] as PromptComponent
@@ -354,7 +360,7 @@ export class ClineProvider implements vscode.WebviewViewProvider {
 			task,
 			images,
 			undefined,
-			experimentalDiffStrategy,
+			Experiments.isEnabled(experiments, EXPERIMENT_IDS.DIFF_STRATEGY),
 		)
 	}
 
@@ -367,7 +373,7 @@ export class ClineProvider implements vscode.WebviewViewProvider {
 			fuzzyMatchThreshold,
 			mode,
 			customInstructions: globalInstructions,
-			experimentalDiffStrategy,
+			experiments,
 		} = await this.getState()
 
 		const modePrompt = customModePrompts?.[mode] as PromptComponent
@@ -382,7 +388,7 @@ export class ClineProvider implements vscode.WebviewViewProvider {
 			undefined,
 			undefined,
 			historyItem,
-			experimentalDiffStrategy,
+			Experiments.isEnabled(experiments, EXPERIMENT_IDS.DIFF_STRATEGY),
 		)
 	}
 
@@ -1044,14 +1050,14 @@ export class ClineProvider implements vscode.WebviewViewProvider {
 								diffEnabled,
 								mcpEnabled,
 								fuzzyMatchThreshold,
-								experimentalDiffStrategy,
+								experiments,
 							} = await this.getState()
 
 							// Create diffStrategy based on current model and settings
 							const diffStrategy = getDiffStrategy(
 								apiConfiguration.apiModelId || apiConfiguration.openRouterModelId || "",
 								fuzzyMatchThreshold,
-								experimentalDiffStrategy,
+								Experiments.isEnabled(experiments, EXPERIMENT_IDS.DIFF_STRATEGY),
 							)
 							const cwd =
 								vscode.workspace.workspaceFolders?.map((folder) => folder.uri.fsPath).at(0) || ""
@@ -1072,6 +1078,7 @@ export class ClineProvider implements vscode.WebviewViewProvider {
 								customInstructions,
 								preferredLanguage,
 								diffEnabled,
+								experiments,
 							)
 
 							await this.postMessageToWebview({
@@ -1207,14 +1214,28 @@ export class ClineProvider implements vscode.WebviewViewProvider {
 							vscode.window.showErrorMessage("Failed to get list api configuration")
 						}
 						break
-					case "experimentalDiffStrategy":
-						await this.updateGlobalState("experimentalDiffStrategy", message.bool ?? false)
-						// Update diffStrategy in current Cline instance if it exists
-						if (this.cline) {
-							await this.cline.updateDiffStrategy(message.bool ?? false)
+					case "updateExperimental": {
+						if (!message.values) {
+							break
 						}
+
+						const updatedExperiments = {
+							...((await this.getGlobalState("experiments")) ?? experimentDefault),
+							...message.values,
+						}
+
+						await this.updateGlobalState("experiments", updatedExperiments)
+
+						// Update diffStrategy in current Cline instance if it exists
+						if (message.values[EXPERIMENT_IDS.DIFF_STRATEGY] !== undefined && this.cline) {
+							await this.cline.updateDiffStrategy(
+								Experiments.isEnabled(updatedExperiments, EXPERIMENT_IDS.DIFF_STRATEGY),
+							)
+						}
+
 						await this.postStateToWebview()
 						break
+					}
 					case "updateMcpTimeout":
 						if (message.serverName && typeof message.timeout === "number") {
 							try {
@@ -1873,8 +1894,8 @@ export class ClineProvider implements vscode.WebviewViewProvider {
 			customModePrompts,
 			customSupportPrompts,
 			enhancementApiConfigId,
-			experimentalDiffStrategy,
 			autoApprovalEnabled,
+			experiments,
 		} = await this.getState()
 
 		const allowedCommands = vscode.workspace.getConfiguration("roo-cline").get<string[]>("allowedCommands") || []
@@ -1914,9 +1935,9 @@ export class ClineProvider implements vscode.WebviewViewProvider {
 			customModePrompts: customModePrompts ?? {},
 			customSupportPrompts: customSupportPrompts ?? {},
 			enhancementApiConfigId,
-			experimentalDiffStrategy: experimentalDiffStrategy ?? false,
 			autoApprovalEnabled: autoApprovalEnabled ?? false,
 			customModes: await this.customModesManager.getCustomModes(),
+			experiments: experiments ?? experimentDefault,
 		}
 	}
 
@@ -2039,9 +2060,9 @@ export class ClineProvider implements vscode.WebviewViewProvider {
 			customModePrompts,
 			customSupportPrompts,
 			enhancementApiConfigId,
-			experimentalDiffStrategy,
 			autoApprovalEnabled,
 			customModes,
+			experiments,
 		] = await Promise.all([
 			this.getGlobalState("apiProvider") as Promise<ApiProvider | undefined>,
 			this.getGlobalState("apiModelId") as Promise<string | undefined>,
@@ -2109,9 +2130,9 @@ export class ClineProvider implements vscode.WebviewViewProvider {
 			this.getGlobalState("customModePrompts") as Promise<CustomModePrompts | undefined>,
 			this.getGlobalState("customSupportPrompts") as Promise<CustomSupportPrompts | undefined>,
 			this.getGlobalState("enhancementApiConfigId") as Promise<string | undefined>,
-			this.getGlobalState("experimentalDiffStrategy") as Promise<boolean | undefined>,
 			this.getGlobalState("autoApprovalEnabled") as Promise<boolean | undefined>,
 			this.customModesManager.getCustomModes(),
+			this.getGlobalState("experiments") as Promise<Record<string, boolean> | undefined>,
 		])
 
 		let apiProvider: ApiProvider
@@ -2225,7 +2246,7 @@ export class ClineProvider implements vscode.WebviewViewProvider {
 			customModePrompts: customModePrompts ?? {},
 			customSupportPrompts: customSupportPrompts ?? {},
 			enhancementApiConfigId,
-			experimentalDiffStrategy: experimentalDiffStrategy ?? false,
+			experiments: experiments ?? experimentDefault,
 			autoApprovalEnabled: autoApprovalEnabled ?? false,
 			customModes,
 		}

src/core/webview/__tests__/ClineProvider.test.ts

@@ -4,6 +4,7 @@ import { ExtensionMessage, ExtensionState } from "../../../shared/ExtensionMessa
 import { setSoundEnabled } from "../../../utils/sound"
 import { defaultModeSlug, modes } from "../../../shared/modes"
 import { addCustomInstructions } from "../../prompts/sections/custom-instructions"
+import { experimentDefault, experiments } from "../../../shared/experiments"
 
 // Mock custom-instructions module
 const mockAddCustomInstructions = jest.fn()
@@ -320,6 +321,7 @@ describe("ClineProvider", () => {
 			requestDelaySeconds: 5,
 			mode: defaultModeSlug,
 			customModes: [],
+			experiments: experimentDefault,
 		}
 
 		const message: ExtensionMessage = {
@@ -617,6 +619,7 @@ describe("ClineProvider", () => {
 			mode: "code",
 			diffEnabled: true,
 			fuzzyMatchThreshold: 1.0,
+			experiments: experimentDefault,
 		} as any)
 
 		// Reset Cline mock
@@ -636,7 +639,7 @@ describe("ClineProvider", () => {
 			"Test task",
 			undefined,
 			undefined,
-			undefined,
+			false,
 		)
 	})
 	test("handles mode-specific custom instructions updates", async () => {
@@ -887,6 +890,7 @@ describe("ClineProvider", () => {
 				},
 				mcpEnabled: true,
 				mode: "code" as const,
+				experiments: experimentDefault,
 			} as any)
 
 			const handler1 = getMessageHandler()
@@ -918,6 +922,7 @@ describe("ClineProvider", () => {
 				},
 				mcpEnabled: false,
 				mode: "code" as const,
+				experiments: experimentDefault,
 			} as any)
 
 			const handler2 = getMessageHandler()
@@ -985,6 +990,7 @@ describe("ClineProvider", () => {
 				experimentalDiffStrategy: true,
 				diffEnabled: true,
 				fuzzyMatchThreshold: 0.8,
+				experiments: experimentDefault,
 			} as any)
 
 			// Mock SYSTEM_PROMPT to verify diffStrategy and diffEnabled are passed
@@ -1012,6 +1018,7 @@ describe("ClineProvider", () => {
 				undefined, // effectiveInstructions
 				undefined, // preferredLanguage
 				true, // diffEnabled
+				experimentDefault,
 			)
 
 			// Run the test again to verify it's consistent
@@ -1034,6 +1041,7 @@ describe("ClineProvider", () => {
 				experimentalDiffStrategy: true,
 				diffEnabled: false,
 				fuzzyMatchThreshold: 0.8,
+				experiments: experimentDefault,
 			} as any)
 
 			// Mock SYSTEM_PROMPT to verify diffEnabled is passed as false
@@ -1061,6 +1069,7 @@ describe("ClineProvider", () => {
 				undefined, // effectiveInstructions
 				undefined, // preferredLanguage
 				false, // diffEnabled
+				experimentDefault,
 			)
 		})
 
@@ -1077,6 +1086,7 @@ describe("ClineProvider", () => {
 				mode: "architect",
 				mcpEnabled: false,
 				browserViewportSize: "900x600",
+				experiments: experimentDefault,
 			} as any)
 
 			// Mock SYSTEM_PROMPT to call addCustomInstructions

src/shared/ExtensionMessage.ts

@@ -108,7 +108,7 @@ export interface ExtensionState {
 	mode: Mode
 	modeApiConfigs?: Record<Mode, string>
 	enhancementApiConfigId?: string
-	experimentalDiffStrategy?: boolean
+	experiments: Record<string, boolean> // Map of experiment IDs to their enabled state
 	autoApprovalEnabled?: boolean
 	customModes: ModeConfig[]
 	toolRequirements?: Record<string, boolean> // Map of tool names to their requirements (e.g. {"apply_diff": true} if diffEnabled)

src/shared/WebviewMessage.ts

@@ -75,7 +75,7 @@ export interface WebviewMessage {
 		| "getSystemPrompt"
 		| "systemPrompt"
 		| "enhancementApiConfigId"
-		| "experimentalDiffStrategy"
+		| "updateExperimental"
 		| "autoApprovalEnabled"
 		| "updateCustomMode"
 		| "deleteCustomMode"

src/shared/__tests__/modes.test.ts

@@ -14,6 +14,12 @@ describe("isToolAllowedForMode", () => {
 			roleDefinition: "You are a CSS editor",
 			groups: ["read", ["edit", { fileRegex: "\\.css$" }], "browser"],
 		},
+		{
+			slug: "test-exp-mode",
+			name: "Test Exp Mode",
+			roleDefinition: "You are an experimental tester",
+			groups: ["read", "edit", "browser"],
+		},
 	]
 
 	it("allows always available tools", () => {
@@ -240,6 +246,87 @@ describe("isToolAllowedForMode", () => {
 
 		expect(isToolAllowedForMode("write_to_file", "markdown-editor", customModes, toolRequirements)).toBe(false)
 	})
+
+	describe("experimental tools", () => {
+		it("disables tools when experiment is disabled", () => {
+			const experiments = {
+				search_and_replace: false,
+				insert_code_block: false,
+			}
+
+			expect(
+				isToolAllowedForMode(
+					"search_and_replace",
+					"test-exp-mode",
+					customModes,
+					undefined,
+					undefined,
+					experiments,
+				),
+			).toBe(false)
+
+			expect(
+				isToolAllowedForMode(
+					"insert_code_block",
+					"test-exp-mode",
+					customModes,
+					undefined,
+					undefined,
+					experiments,
+				),
+			).toBe(false)
+		})
+
+		it("allows tools when experiment is enabled", () => {
+			const experiments = {
+				search_and_replace: true,
+				insert_code_block: true,
+			}
+
+			expect(
+				isToolAllowedForMode(
+					"search_and_replace",
+					"test-exp-mode",
+					customModes,
+					undefined,
+					undefined,
+					experiments,
+				),
+			).toBe(true)
+
+			expect(
+				isToolAllowedForMode(
+					"insert_code_block",
+					"test-exp-mode",
+					customModes,
+					undefined,
+					undefined,
+					experiments,
+				),
+			).toBe(true)
+		})
+
+		it("allows non-experimental tools when experiments are disabled", () => {
+			const experiments = {
+				search_and_replace: false,
+				insert_code_block: false,
+			}
+
+			expect(
+				isToolAllowedForMode("read_file", "markdown-editor", customModes, undefined, undefined, experiments),
+			).toBe(true)
+			expect(
+				isToolAllowedForMode(
+					"write_to_file",
+					"markdown-editor",
+					customModes,
+					undefined,
+					{ path: "test.md" },
+					experiments,
+				),
+			).toBe(true)
+		})
+	})
 })
 
 describe("FileRestrictionError", () => {

src/shared/experiments.ts

@@ -0,0 +1,63 @@
+export interface ExperimentConfig {
+	id: string
+	name: string
+	description: string
+	enabled: boolean
+}
+
+export const EXPERIMENT_IDS = {
+	DIFF_STRATEGY: "experimentalDiffStrategy",
+	SEARCH_AND_REPLACE: "search_and_replace",
+	INSERT_BLOCK: "insert_code_block",
+} as const
+
+export type ExperimentId = keyof typeof EXPERIMENT_IDS
+
+export const experimentConfigsMap: Record<ExperimentId, ExperimentConfig> = {
+	DIFF_STRATEGY: {
+		id: EXPERIMENT_IDS.DIFF_STRATEGY,
+		name: "Use experimental unified diff strategy",
+		description:
+			"Enable the experimental unified diff strategy. This strategy might reduce the number of retries caused by model errors but may cause unexpected behavior or incorrect edits. Only enable if you understand the risks and are willing to carefully review all changes.",
+		enabled: false,
+	},
+	SEARCH_AND_REPLACE: {
+		id: EXPERIMENT_IDS.SEARCH_AND_REPLACE,
+		name: "Use experimental search and replace tool",
+		description:
+			"Enable the experimental Search and Replace tool. This tool allows Roo to search and replace term. Can be run multiple search and replace in sequence at once request.",
+		enabled: false,
+	},
+	INSERT_BLOCK: {
+		id: EXPERIMENT_IDS.INSERT_BLOCK,
+		name: "Use experimental insert block tool",
+
+		description:
+			"Enable the experimental insert block tool. This tool allows Roo to insert code blocks into files. Can be insert multiple blocks at once.",
+		enabled: false,
+	},
+}
+
+// Keep the array version for backward compatibility
+export const experimentConfigs = Object.values(experimentConfigsMap)
+export const experimentDefault = Object.fromEntries(
+	Object.entries(experimentConfigsMap).map(([_, config]) => [config.id, config.enabled]),
+)
+
+export const experiments = {
+	get: (id: ExperimentId): ExperimentConfig | undefined => {
+		return experimentConfigsMap[id]
+	},
+	isEnabled: (experimentsConfig: Record<string, boolean>, id: string): boolean => {
+		return experimentsConfig[id] ?? experimentDefault[id]
+	},
+} as const
+
+// Expose experiment details for UI - pre-compute from map for better performance
+export const experimentLabels = Object.fromEntries(
+	Object.values(experimentConfigsMap).map((config) => [config.id, config.name]),
+) as Record<string, string>
+
+export const experimentDescriptions = Object.fromEntries(
+	Object.values(experimentConfigsMap).map((config) => [config.id, config.description]),
+) as Record<string, string>

src/shared/modes.ts

@@ -160,12 +160,19 @@ export function isToolAllowedForMode(
 	customModes: ModeConfig[],
 	toolRequirements?: Record<string, boolean>,
 	toolParams?: Record<string, any>, // All tool parameters
+	experiments?: Record<string, boolean>,
 ): boolean {
 	// Always allow these tools
 	if (ALWAYS_AVAILABLE_TOOLS.includes(tool as any)) {
 		return true
 	}
 
+	if (experiments && tool in experiments) {
+		if (!experiments[tool]) {
+			return false
+		}
+	}
+
 	// Check tool requirements if any exist
 	if (toolRequirements && tool in toolRequirements) {
 		if (!toolRequirements[tool]) {