diff --git a/src/core/assistant-message/NativeToolCallParser.ts b/src/core/assistant-message/NativeToolCallParser.ts
index 87750314fa6..a16492873a9 100644
--- a/src/core/assistant-message/NativeToolCallParser.ts
+++ b/src/core/assistant-message/NativeToolCallParser.ts
@@ -879,6 +879,9 @@ export class NativeToolCallParser {
 				params,
 				partial: false, // Native tool calls are always complete when yielded
 				nativeArgs,
+				// Preserve original args for API history to maintain format consistency
+				// This ensures line_ranges stays as [[1, 50]] instead of being converted to lineRanges
+				rawInput: args,
 			}
 
 			// Preserve original name for API history when an alias was used
diff --git a/src/core/assistant-message/__tests__/NativeToolCallParser.spec.ts b/src/core/assistant-message/__tests__/NativeToolCallParser.spec.ts
index 0e81671cc15..575acc995a7 100644
--- a/src/core/assistant-message/__tests__/NativeToolCallParser.spec.ts
+++ b/src/core/assistant-message/__tests__/NativeToolCallParser.spec.ts
@@ -169,6 +169,49 @@ describe("NativeToolCallParser", () => {
 					])
 				}
 			})
+
+			it("should preserve rawInput with original line_ranges format for API history", () => {
+				const toolCall = {
+					id: "toolu_123",
+					name: "read_file" as const,
+					arguments: JSON.stringify({
+						files: [
+							{
+								path: "src/core/task/Task.ts",
+								line_ranges: [
+									[1920, 1990],
+									[2060, 2120],
+								],
+							},
+						],
+					}),
+				}
+
+				const result = NativeToolCallParser.parseToolCall(toolCall)
+
+				expect(result).not.toBeNull()
+				expect(result?.type).toBe("tool_use")
+				if (result?.type === "tool_use") {
+					// Verify nativeArgs has converted format (lineRanges with objects)
+					const nativeArgs = result.nativeArgs as {
+						files: Array<{ path: string; lineRanges?: Array<{ start: number; end: number }> }>
+					}
+					expect(nativeArgs.files[0].lineRanges).toEqual([
+						{ start: 1920, end: 1990 },
+						{ start: 2060, end: 2120 },
+					])
+
+					// Verify rawInput preserves original format (line_ranges with tuples)
+					expect(result.rawInput).toBeDefined()
+					const rawInput = result.rawInput as {
+						files: Array<{ path: string; line_ranges?: Array<[number, number]> }>
+					}
+					expect(rawInput.files[0].line_ranges).toEqual([
+						[1920, 1990],
+						[2060, 2120],
+					])
+				}
+			})
 		})
 	})
 
diff --git a/src/core/task/Task.ts b/src/core/task/Task.ts
index 8db13bec82b..7f609b5b6ab 100644
--- a/src/core/task/Task.ts
+++ b/src/core/task/Task.ts
@@ -3556,8 +3556,11 @@ export class Task extends EventEmitter<TaskEvents> implements TaskLike {
 							const toolUse = block as import("../../shared/tools").ToolUse
 							const toolCallId = toolUse.id
 							if (toolCallId) {
-								// nativeArgs is already in the correct API format for all tools
-								const input = toolUse.nativeArgs || toolUse.params
+								// Use rawInput to preserve original API format for history consistency.
+								// This ensures parameters like line_ranges stay as [[1, 50]] instead of
+								// being converted to lineRanges with object format [{ start: 1, end: 50 }].
+								// Fall back to nativeArgs for tools that don't have rawInput, then to params for legacy.
+								const input = toolUse.rawInput || toolUse.nativeArgs || toolUse.params
 
 								// Use originalName (alias) if present for API history consistency.
 								// When tool aliases are used (e.g., "edit_file" -> "search_and_replace"),
diff --git a/src/shared/tools.ts b/src/shared/tools.ts
index 4a2bf415925..4fe727ff39e 100644
--- a/src/shared/tools.ts
+++ b/src/shared/tools.ts
@@ -150,6 +150,12 @@ export interface ToolUse<TName extends ToolName = ToolName> {
 	toolUseId?: string // kilocode_change
 	// nativeArgs is properly typed based on TName if it's in NativeToolArgs, otherwise never
 	nativeArgs?: TName extends keyof NativeToolArgs ? NativeToolArgs[TName] : never
+	/**
+	 * The raw input object from the API, preserving original parameter names and formats.
+	 * Used for saving to conversation history to maintain API format consistency.
+	 * For example, read_file keeps `line_ranges` as `[[1, 50]]` instead of converting to `lineRanges`.
+	 */
+	rawInput?: Record<string, unknown>
 }
 
 /**