Fix agent reads to use unsaved Files editor buffers

apps/desktop/src/main/services/ai/tools/readFileRange.test.ts

@@ -35,6 +35,20 @@ describe("createReadFileRangeTool", () => {
   // Happy paths
   // --------------------------------------------------------------------------
 
+  it("prefers unsaved editor buffer text over on-disk content", async () => {
+    const cwd = makeTmpDir("read-dirty-");
+    writeFixtureFile(cwd, "dirty.ts", "saved on disk");
+
+    const tool = createReadFileRangeTool(cwd, {
+      getDirtyFileTextForPath: () => "unsaved in editor",
+    });
+    const result = await tool.execute({ file_path: "dirty.ts" });
+
+    expect(result.error).toBeUndefined();
+    expect(result.content).toContain("unsaved in editor");
+    expect(result.content).not.toContain("saved on disk");
+  });
+
   it("reads an entire file when no offset or limit is given", async () => {
     const cwd = makeTmpDir("read-full-");
     writeFixtureFile(cwd, "sample.ts", FIVE_LINES);

apps/desktop/src/main/services/ai/tools/readFileRange.ts

@@ -2,13 +2,22 @@ import { executableTool as tool } from "./executableTool";
 import { z } from "zod";
 import fs from "node:fs";
 import path from "node:path";
-import { getErrorMessage, readFileWithinRootSecure, resolvePathWithinRoot } from "../../shared/utils";
+import {
+  getErrorMessage,
+  readAgentAccessibleFileBytes,
+  resolvePathWithinRoot,
+  type DirtyFileTextLookup,
+} from "../../shared/utils";
 
 function toDisplayPath(root: string, filePath: string): string {
   return path.relative(root, filePath).replace(/\\/g, "/");
 }
 
-export function createReadFileRangeTool(cwd: string) {
+export type ReadFileRangeToolOptions = {
+  getDirtyFileTextForPath?: DirtyFileTextLookup;
+};
+
+export function createReadFileRangeTool(cwd: string, options: ReadFileRangeToolOptions = {}) {
   return tool({
     description:
       "Read a file's contents with line numbers. Accepts an absolute path or a path relative to the active repo root.",
@@ -40,7 +49,13 @@ export function createReadFileRangeTool(cwd: string) {
           return { content: "", totalLines: 0, error: `Error reading file: ${message}` };
         }
 
-        const raw = readFileWithinRootSecure(root, file_path).toString("utf-8");
+        const raw = (
+          await readAgentAccessibleFileBytes({
+            rootPath: root,
+            resolvedPath: resolvedPath,
+            getDirtyFileTextForPath: options.getDirtyFileTextForPath,
+          })
+        ).toString("utf-8");
         const allLines = raw.split("\n");
         const totalLines = allLines.length;
 

apps/desktop/src/main/services/ai/tools/universalTools.ts

@@ -12,7 +12,13 @@ import { webFetchTool } from "./webFetch";
 import { webSearchTool } from "./webSearch";
 import type { AgentChatApprovalDecision, AgentChatEvent, PendingInputKind, WorkerSandboxConfig } from "../../../../shared/types";
 import { DEFAULT_WORKER_SANDBOX_CONFIG } from "./workerSandboxDefaults";
-import { getErrorMessage, isEnoentError, isWithinDir, resolvePathWithinRoot } from "../../shared/utils";
+import {
+  getErrorMessage,
+  isEnoentError,
+  isWithinDir,
+  resolvePathWithinRoot,
+  type DirtyFileTextLookup,
+} from "../../shared/utils";
 import { terminateProcessTree } from "../../shared/processExecution";
 
 const execFileAsync = promisify(execFile);
@@ -75,6 +81,8 @@ export interface UniversalToolSetOptions {
    * controller and abort it when an external policy event cancels the session.
    */
   registerActiveBash?: (controller: AbortController) => (() => void) | void;
+  /** Prefer unsaved Files-tab editor buffers over on-disk content for readFile. */
+  getDirtyFileTextForPath?: DirtyFileTextLookup;
 }
 
 // ── Permission helpers ──────────────────────────────────────────────
@@ -2708,7 +2716,9 @@ export function createUniversalToolSet(
   // eslint-disable-next-line @typescript-eslint/no-explicit-any
   const tools: Record<string, Tool<any, any>> = {
     // Read-only tools (auto-allowed in all modes)
-    readFile: createReadFileRangeTool(cwd),
+    readFile: createReadFileRangeTool(cwd, {
+      getDirtyFileTextForPath: opts.getDirtyFileTextForPath,
+    }),
     grep: createGrepSearchTool(cwd),
     glob: createGlobSearchTool(cwd),
     listDir: createListDirTool(cwd),