refactor(read_file): Codex-inspired indentation mode with simplified API

- Replace multi-file read_file with single-file-per-call design
- Add two reading modes: slice (default) and indentation
- Implement bidirectional expansion algorithm for indentation mode
- Add line truncation (500 chars) and limit (2000 lines default)
- Remove legacy token-budget-based reading approach
- Remove maxReadFileLine setting (replaced by limit parameter)
- Add new IndentationParams and ReadFileParams types
- Clean up stale FileEntry/LineRange types and helpers

Known limitations:
- Lines >500 chars are truncated (content lost)
- No server-side max limit enforcement

Author: hannesrudolph

apps/vscode-e2e/src/suite/tools/read-file.test.ts

@@ -376,7 +376,7 @@ suite.skip("Roo Code read_file Tool", function () {
 		}
 	})
 
-	test("Should read file with line range", async function () {
+	test("Should read file with slice offset/limit", async function () {
 		const api = globalThis.api
 		const messages: ClineMessage[] = []
 		let taskCompleted = false
@@ -446,7 +446,7 @@ suite.skip("Roo Code read_file Tool", function () {
 					alwaysAllowReadOnly: true,
 					alwaysAllowReadOnlyOutsideWorkspace: true,
 				},
-				text: `Use the read_file tool to read the file "${fileName}" and show me what's on lines 2, 3, and 4. The file contains lines like "Line 1", "Line 2", etc. Assume the file exists and you can read it directly.`,
+				text: `Use the read_file tool to read the file "${fileName}" using slice mode with offset=2 and limit=3 (1-based offset). The file contains lines like "Line 1", "Line 2", etc. After reading, show me the three lines you read.`,
 			})
 
 			// Wait for task completion
@@ -455,9 +455,8 @@ suite.skip("Roo Code read_file Tool", function () {
 			// Verify tool was executed
 			assert.ok(toolExecuted, "The read_file tool should have been executed")
 
-			// Verify the tool returned the correct lines (when line range is used)
+			// Verify the tool returned the correct lines (offset=2, limit=3 -> lines 2-4)
 			if (toolResult && (toolResult as string).includes(" | ")) {
-				// The result includes line numbers
 				assert.ok(
 					(toolResult as string).includes("2 | Line 2"),
 					"Tool result should include line 2 with line number",

packages/cloud/src/__tests__/CloudSettingsService.parsing.test.ts

@@ -81,7 +81,6 @@ describe("CloudSettingsService - Response Parsing", () => {
 				version: 2,
 				defaultSettings: {
 					maxOpenTabsContext: 10,
-					maxReadFileLine: 1000,
 				},
 				allowList: {
 					allowAll: false,

packages/types/src/cloud.ts

@@ -95,7 +95,6 @@ export const organizationDefaultSettingsSchema = globalSettingsSchema
 	.pick({
 		enableCheckpoints: true,
 		maxOpenTabsContext: true,
-		maxReadFileLine: true,
 		maxWorkspaceFiles: true,
 		showRooIgnoredFiles: true,
 		terminalCommandDelay: true,
@@ -109,7 +108,6 @@ export const organizationDefaultSettingsSchema = globalSettingsSchema
 	.merge(
 		z.object({
 			maxOpenTabsContext: z.number().int().nonnegative().optional(),
-			maxReadFileLine: z.number().int().gte(-1).optional(),
 			maxWorkspaceFiles: z.number().int().nonnegative().optional(),
 			terminalCommandDelay: z.number().int().nonnegative().optional(),
 			terminalOutputLineLimit: z.number().int().nonnegative().optional(),

packages/types/src/global-settings.ts

@@ -143,7 +143,6 @@ export const globalSettingsSchema = z.object({
 	maxWorkspaceFiles: z.number().optional(),
 	showRooIgnoredFiles: z.boolean().optional(),
 	enableSubfolderRules: z.boolean().optional(),
-	maxReadFileLine: z.number().optional(),
 	maxImageFileSize: z.number().optional(),
 	maxTotalImageSize: z.number().optional(),
 
@@ -359,7 +358,6 @@ export const EVALS_SETTINGS: RooCodeSettings = {
 	maxWorkspaceFiles: 200,
 	maxGitStatusFiles: 20,
 	showRooIgnoredFiles: true,
-	maxReadFileLine: -1, // -1 to enable full file reading.
 
 	includeDiagnosticMessages: true,
 	maxDiagnosticMessages: 50,

packages/types/src/tool-params.ts

@@ -2,14 +2,45 @@
  * Tool parameter type definitions for native protocol
  */
 
-export interface LineRange {
-	start: number
-	end: number
+/**
+ * Read mode for the read_file tool.
+ * - "slice": Simple offset/limit reading (default)
+ * - "indentation": Semantic block extraction based on code structure
+ */
+export type ReadFileMode = "slice" | "indentation"
+
+/**
+ * Indentation-mode configuration for the read_file tool.
+ */
+export interface IndentationParams {
+	/** 1-based line number to anchor indentation extraction (defaults to offset) */
+	anchor_line?: number
+	/** Maximum indentation levels to include above anchor (0 = unlimited) */
+	max_levels?: number
+	/** Include sibling blocks at the same indentation level */
+	include_siblings?: boolean
+	/** Include file header (imports, comments at top) */
+	include_header?: boolean
+	/** Hard cap on lines returned for indentation mode */
+	max_lines?: number
 }
 
-export interface FileEntry {
+/**
+ * Parameters for the read_file tool.
+ *
+ * NOTE: This is the canonical, single-file-per-call shape.
+ */
+export interface ReadFileParams {
+	/** Path to the file, relative to workspace */
 	path: string
-	lineRanges?: LineRange[]
+	/** Reading mode: "slice" (default) or "indentation" */
+	mode?: ReadFileMode
+	/** 1-based line number to start reading from (slice mode, default: 1) */
+	offset?: number
+	/** Maximum number of lines to read (default: 2000) */
+	limit?: number
+	/** Indentation-mode configuration (only used when mode === "indentation") */
+	indentation?: IndentationParams
 }
 
 export interface Coordinate {

packages/types/src/vscode-extension-host.ts

@@ -64,7 +64,6 @@ export interface ExtensionMessage {
 		| "remoteBrowserEnabled"
 		| "ttsStart"
 		| "ttsStop"
-		| "maxReadFileLine"
 		| "fileSearchResults"
 		| "toggleApiConfigPin"
 		| "acceptInput"
@@ -354,7 +353,6 @@ export type ExtensionState = Pick<
 	maxWorkspaceFiles: number // Maximum number of files to include in current working directory details (0-500)
 	showRooIgnoredFiles: boolean // Whether to show .rooignore'd files in listings
 	enableSubfolderRules: boolean // Whether to load rules from subdirectories
-	maxReadFileLine: number // Maximum number of lines to read from a file before truncating
 	maxImageFileSize: number // Maximum size of image files to process in MB
 	maxTotalImageSize: number // Maximum total size for all images in a single read operation in MB
 

src/__tests__/command-mentions.spec.ts

@@ -36,7 +36,6 @@ describe("Command Mentions", () => {
 			false, // showRooIgnoredFiles
 			true, // includeDiagnosticMessages
 			50, // maxDiagnosticMessages
-			undefined, // maxReadFileLine
 		)
 	}
 

src/api/providers/__tests__/bedrock-native-tools.spec.ts

@@ -135,23 +135,18 @@ describe("AwsBedrockHandler Native Tool Calling", () => {
 						parameters: {
 							type: "object",
 							properties: {
-								files: {
-									type: "array",
-									items: {
-										type: "object",
-										properties: {
-											path: { type: "string" },
-											line_ranges: {
-												type: ["array", "null"],
-												items: { type: "integer" },
-												description: "Optional line ranges",
-											},
+								path: { type: "string" },
+								indentation: {
+									type: ["object", "null"],
+									properties: {
+										anchor_line: {
+											type: ["integer", "null"],
+											description: "Optional anchor line",
 										},
-										required: ["path", "line_ranges"],
 									},
 								},
 							},
-							required: ["files"],
+							required: ["path"],
 						},
 					},
 				},
@@ -167,15 +162,14 @@ describe("AwsBedrockHandler Native Tool Calling", () => {
 			expect(executeCommandSchema.properties.cwd.type).toBeUndefined()
 			expect(executeCommandSchema.properties.cwd.description).toBe("Working directory (optional)")
 
-			// Second tool: line_ranges should be transformed from type: ["array", "null"] to anyOf
-			// with items moved inside the array variant (required by GPT-5-mini strict schema validation)
+			// Second tool: nested nullable object should be transformed from type: ["object", "null"] to anyOf
 			const readFileSchema = bedrockTools[1].toolSpec.inputSchema.json as any
-			const lineRanges = readFileSchema.properties.files.items.properties.line_ranges
-			expect(lineRanges.anyOf).toEqual([{ type: "array", items: { type: "integer" } }, { type: "null" }])
-			expect(lineRanges.type).toBeUndefined()
-			// items should now be inside the array variant, not at root
-			expect(lineRanges.items).toBeUndefined()
-			expect(lineRanges.description).toBe("Optional line ranges")
+			const indentation = readFileSchema.properties.indentation
+			expect(indentation.anyOf).toBeDefined()
+			expect(indentation.type).toBeUndefined()
+			// Object-level schema properties are preserved at the root, not inside the anyOf object variant
+			expect(indentation.additionalProperties).toBe(false)
+			expect(indentation.properties.anchor_line.anyOf).toEqual([{ type: "integer" }, { type: "null" }])
 		})
 
 		it("should filter non-function tools", () => {

src/core/assistant-message/NativeToolCallParser.ts

@@ -1,6 +1,6 @@
 import { parseJSON } from "partial-json"
 
-import { type ToolName, toolNames, type FileEntry } from "@roo-code/types"
+import { type ToolName, toolNames } from "@roo-code/types"
 import { customToolRegistry } from "@roo-code/core"
 
 import {
@@ -313,43 +313,17 @@ export class NativeToolCallParser {
 		return finalToolUse
 	}
 
-	/**
-	 * Convert raw file entries from API (with line_ranges) to FileEntry objects
-	 * (with lineRanges). Handles multiple formats for compatibility:
-	 *
-	 * New tuple format: { path: string, line_ranges: [[1, 50], [100, 150]] }
-	 * Object format: { path: string, line_ranges: [{ start: 1, end: 50 }] }
-	 * Legacy string format: { path: string, line_ranges: ["1-50"] }
-	 *
-	 * Returns: { path: string, lineRanges: [{ start: 1, end: 50 }] }
-	 */
-	private static convertFileEntries(files: any[]): FileEntry[] {
-		return files.map((file: any) => {
-			const entry: FileEntry = { path: file.path }
-			if (file.line_ranges && Array.isArray(file.line_ranges)) {
-				entry.lineRanges = file.line_ranges
-					.map((range: any) => {
-						// Handle tuple format: [start, end]
-						if (Array.isArray(range) && range.length >= 2) {
-							return { start: Number(range[0]), end: Number(range[1]) }
-						}
-						// Handle object format: { start: number, end: number }
-						if (typeof range === "object" && range !== null && "start" in range && "end" in range) {
-							return { start: Number(range.start), end: Number(range.end) }
-						}
-						// Handle legacy string format: "1-50"
-						if (typeof range === "string") {
-							const match = range.match(/^(\d+)-(\d+)$/)
-							if (match) {
-								return { start: parseInt(match[1], 10), end: parseInt(match[2], 10) }
-							}
-						}
-						return null
-					})
-					.filter(Boolean)
+	private static coerceOptionalNumber(value: unknown): number | undefined {
+		if (typeof value === "number" && Number.isFinite(value)) {
+			return value
+		}
+		if (typeof value === "string") {
+			const n = Number(value)
+			if (Number.isFinite(n)) {
+				return n
 			}
-			return entry
-		})
+		}
+		return undefined
 	}
 
 	/**
@@ -380,8 +354,26 @@ export class NativeToolCallParser {
 
 		switch (name) {
 			case "read_file":
-				if (partialArgs.files && Array.isArray(partialArgs.files)) {
-					nativeArgs = { files: this.convertFileEntries(partialArgs.files) }
+				if (partialArgs.path !== undefined) {
+					nativeArgs = {
+						path: partialArgs.path,
+						mode: partialArgs.mode,
+						offset: this.coerceOptionalNumber(partialArgs.offset),
+						limit: this.coerceOptionalNumber(partialArgs.limit),
+						indentation:
+							partialArgs.indentation && typeof partialArgs.indentation === "object"
+								? {
+										anchor_line: this.coerceOptionalNumber(partialArgs.indentation.anchor_line),
+										max_levels: this.coerceOptionalNumber(partialArgs.indentation.max_levels),
+										include_siblings: this.coerceOptionalBoolean(
+											partialArgs.indentation.include_siblings,
+										),
+										include_header: this.coerceOptionalBoolean(
+											partialArgs.indentation.include_header,
+										),
+									}
+								: undefined,
+					}
 				}
 				break
 
@@ -641,13 +633,6 @@ export class NativeToolCallParser {
 			const params: Partial<Record<ToolParamName, string>> = {}
 
 			for (const [key, value] of Object.entries(args)) {
-				// Skip complex parameters that have been migrated to nativeArgs.
-				// For read_file, the 'files' parameter is a FileEntry[] array that can't be
-				// meaningfully stringified. The properly typed data is in nativeArgs instead.
-				if (resolvedName === "read_file" && key === "files") {
-					continue
-				}
-
 				// Validate parameter name
 				if (!toolParamNames.includes(key as ToolParamName) && !customToolRegistry.has(resolvedName)) {
 					console.warn(`Unknown parameter '${key}' for tool '${resolvedName}'`)
@@ -667,8 +652,24 @@ export class NativeToolCallParser {
 
 			switch (resolvedName) {
 				case "read_file":
-					if (args.files && Array.isArray(args.files)) {
-						nativeArgs = { files: this.convertFileEntries(args.files) } as NativeArgsFor<TName>
+					if (args.path !== undefined) {
+						nativeArgs = {
+							path: args.path,
+							mode: args.mode,
+							offset: this.coerceOptionalNumber(args.offset),
+							limit: this.coerceOptionalNumber(args.limit),
+							indentation:
+								args.indentation && typeof args.indentation === "object"
+									? {
+											anchor_line: this.coerceOptionalNumber(args.indentation.anchor_line),
+											max_levels: this.coerceOptionalNumber(args.indentation.max_levels),
+											include_siblings: this.coerceOptionalBoolean(
+												args.indentation.include_siblings,
+											),
+											include_header: this.coerceOptionalBoolean(args.indentation.include_header),
+										}
+									: undefined,
+						} as NativeArgsFor<TName>
 					}
 					break