Fix agent reads to use unsaved Files editor buffers

getDirtyFileTextForPath was wired from the renderer but never consulted
on agent read paths. readFile tools and chat attachments always read disk,
so agents saw stale content when the user had unsaved edits in the Files tab.

Add readAgentAccessibleFileBytes and route universal readFile, Claude/Codex
attachments, and orchestration tools through it.

Co-authored-by: Arul Sharma <arul28@users.noreply.github.com>

Author: cursoragent

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 +2,23 @@ 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,
+  readFileWithinRootSecure,
+  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 +50,13 @@ 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),

apps/desktop/src/main/services/chat/agentChatService.test.ts

@@ -14457,11 +14457,11 @@ describe("createAgentChatService", () => {
       );
     });
 
-  it("preserves original attachments across local auto-continuation retries", () => {
+  it("preserves original attachments across local auto-continuation retries", async () => {
       const resolvedPath = path.join(tmpRoot, "note.txt");
       fs.writeFileSync(resolvedPath, "remember this", "utf8");
 
-      const streamMessages = buildOpenCodeStreamMessages({
+      const streamMessages = await buildOpenCodeStreamMessages({
         messages: [
           {
             role: "user",

apps/desktop/src/main/services/chat/agentChatService.ts

@@ -34,7 +34,7 @@ import type {
   WarmQuery,
 } from "@anthropic-ai/claude-agent-sdk";
 import { z, type ZodType } from "zod";
-import { buildClaudeV2Message, inferAttachmentMediaType } from "./buildClaudeV2Message";
+import { buildClaudeV2MessageAsync, inferAttachmentMediaType } from "./buildClaudeV2Message";
 import { ClaudeInputPump } from "./claudeInputPump";
 import {
   isCorruptThinkingTranscriptError,
@@ -87,6 +87,7 @@ import {
   hasNullByte,
   isEnoentError,
   nowIso,
+  readAgentAccessibleFileBytes,
   readFileWithinRootSecure,
   resolvePathWithinRoot,
   stableStringify,
@@ -3105,15 +3106,16 @@ function normalizeClaudeTodoItems(
   return items.length ? items : null;
 }
 
-function buildStreamingUserContent(
+async function buildStreamingUserContent(
   args: {
     baseText: string;
     attachments: ResolvedAgentChatFileRef[];
     runtimeKind: "claude" | "opencode";
     modelDescriptor?: ModelDescriptor;
     logger?: Logger;
+    readAttachmentBytes: (attachment: ResolvedAgentChatFileRef) => Promise<Buffer>;
   },
-): UserContent {
+): Promise<UserContent> {
   if (!args.attachments.length) {
     return args.baseText;
   }
@@ -3131,7 +3133,7 @@ function buildStreamingUserContent(
         });
         continue;
       }
-      const data = readFileWithinRootSecure(attachment._rootPath, attachment._resolvedPath);
+      const data = await args.readAttachmentBytes(attachment);
       const mediaType = inferAttachmentMediaType(attachment);
 
       if (attachment.type === "image") {
@@ -3185,14 +3187,24 @@ function buildStreamingUserContent(
   return parts;
 }
 
-export function buildOpenCodeStreamMessages(args: {
+export async function buildOpenCodeStreamMessages(args: {
   messages: Array<{ role: string; content: string }>;
   persistedTurnUserMessageIndex: number;
   resolvedAttachments: ResolvedAgentChatFileRef[];
   modelDescriptor: ModelDescriptor;
   logger?: Logger;
-}): ModelMessage[] {
-  return args.messages.map((message, index): ModelMessage => {
+  getDirtyFileTextForPath?: (absPath: string) => string | undefined | Promise<string | undefined>;
+}): Promise<ModelMessage[]> {
+  const readAttachmentBytes = args.getDirtyFileTextForPath
+    ? async (attachment: ResolvedAgentChatFileRef) => readAgentAccessibleFileBytes({
+      rootPath: attachment._rootPath,
+      resolvedPath: attachment._resolvedPath,
+      getDirtyFileTextForPath: args.getDirtyFileTextForPath,
+    })
+    : async (attachment: ResolvedAgentChatFileRef) =>
+      readFileWithinRootSecure(attachment._rootPath, attachment._resolvedPath);
+
+  const mapped = await Promise.all(args.messages.map(async (message, index): Promise<ModelMessage> => {
     const isPersistedTurnUserMessage = index === args.persistedTurnUserMessageIndex && message.role === "user";
     if (!isPersistedTurnUserMessage) {
       return {
@@ -3203,15 +3215,17 @@ export function buildOpenCodeStreamMessages(args: {
 
     return {
       role: "user",
-      content: buildStreamingUserContent({
+      content: await buildStreamingUserContent({
         baseText: message.content,
         attachments: args.resolvedAttachments,
         runtimeKind: "opencode",
         modelDescriptor: args.modelDescriptor,
         logger: args.logger,
+        readAttachmentBytes,
       }),
     };
-  });
+  }));
+  return mapped;
 }
 
 function buildExecutionModeDirective(
@@ -4717,6 +4731,14 @@ export function createAgentChatService(args: {
   if (!getDirtyFileTextForPath) {
     throw new Error("createAgentChatService: getDirtyFileTextForPath is required");
   }
+
+  const readResolvedAttachmentBytes = async (
+    attachment: ResolvedAgentChatFileRef,
+  ): Promise<Buffer> => readAgentAccessibleFileBytes({
+    rootPath: attachment._rootPath,
+    resolvedPath: attachment._resolvedPath,
+    getDirtyFileTextForPath,
+  });
   if (!issueInventoryService) {
     throw new Error("Issue inventory service is required to initialize agent chat.");
   }
@@ -4777,8 +4799,8 @@ export function createAgentChatService(args: {
     });
   };
 
-  const stageAttachmentForCodexInput = (attachment: ResolvedAgentChatFileRef): string => {
-    const content = readFileWithinRootSecure(attachment._rootPath, attachment._resolvedPath);
+  const stageAttachmentForCodexInput = async (attachment: ResolvedAgentChatFileRef): Promise<string> => {
+    const content = await readResolvedAttachmentBytes(attachment);
     const stagedDir = path.join(layout.tmpDir, "agent-chat-attachments");
     fs.mkdirSync(stagedDir, { recursive: true });
     const baseName = path.basename(attachment.path) || path.basename(attachment._resolvedPath) || "attachment";
@@ -8401,6 +8423,7 @@ export function createAgentChatService(args: {
     managed: ManagedChatSession,
   ): UniversalToolSetOptions => ({
     permissionMode: toHarnessPermissionMode(managed.session.permissionMode),
+    getDirtyFileTextForPath,
     getTodoItems: () => managed.todoItems,
     onTodoUpdate: (items) => {
       emitChatEvent(managed, {
@@ -9581,7 +9604,7 @@ export function createAgentChatService(args: {
         input.push({ type: "image", url: attachment.url });
         continue;
       }
-      const stagedPath = stageAttachmentForCodexInput(attachment);
+      const stagedPath = await stageAttachmentForCodexInput(attachment);
       if (attachment.type === "image") {
         input.push({ type: "localImage", path: stagedPath });
         continue;
@@ -10025,10 +10048,11 @@ export function createAgentChatService(args: {
 
       // Build the message after permission-mode recovery, because rebuilding a
       // fresh Claude SDK session clears runtime.sdkSessionId.
-      const messageToSend = buildClaudeV2Message(basePromptText, resolvedAttachments, {
+      const messageToSend = await buildClaudeV2MessageAsync(basePromptText, resolvedAttachments, {
         baseDir: managed.laneWorktreePath,
         sessionId: runtime.sdkSessionId,
         forceUserMessage: true,
+        getDirtyFileTextForPath,
       }) as unknown as SDKUserMessage;
       messageToSend.uuid = userMessageId;
       messageToSend.timestamp = new Date().toISOString();
@@ -17384,34 +17408,25 @@ export function createAgentChatService(args: {
   /** Maximum bytes to inline for a non-image chat attachment. */
   const MAX_INLINE_BYTES = 512 * 1024; // 512 KB
 
-  const buildAgentPromptBlocks = (
+  const buildAgentPromptBlocks = async (
     promptText: string,
     resolvedAttachments: ResolvedAgentChatFileRef[],
-  ): Array<{ type: "text"; text: string } | { type: "image"; data: string; mimeType: string }> => {
+  ): Promise<Array<{ type: "text"; text: string } | { type: "image"; data: string; mimeType: string }>> => {
     const blocks: Array<
       { type: "text"; text: string } | { type: "image"; data: string; mimeType: string }
     > = [{ type: "text", text: promptText }];
     for (const attachment of resolvedAttachments) {
       try {
-        // Check file size before reading the full contents into memory.
-        let fileSize: number;
-        try {
-          fileSize = fs.statSync(attachment._resolvedPath).size;
-        } catch {
-          // stat failed -- skip unreadable attachment
-          continue;
-        }
+        const buf = await readResolvedAttachmentBytes(attachment);
 
         if (attachment.type === "image") {
-          const buf = readFileWithinRootSecure(attachment._rootPath, attachment._resolvedPath);
           blocks.push({
             type: "image",
             data: buf.toString("base64"),
             mimeType: guessImageMimeForPath(attachment._resolvedPath),
           });
-        } else if (fileSize <= MAX_INLINE_BYTES) {
+        } else if (buf.length <= MAX_INLINE_BYTES) {
           // Non-image file attachment -- include content as text if not binary
-          const buf = readFileWithinRootSecure(attachment._rootPath, attachment._resolvedPath);
           if (hasNullByte(buf)) {
             blocks.push({
               type: "text",
@@ -17428,7 +17443,7 @@ export function createAgentChatService(args: {
           // File is too large to inline -- push a placeholder with a truncated preview.
           blocks.push({
             type: "text",
-            text: `[File: ${attachment.path} omitted: size ${fileSize} bytes]`,
+            text: `[File: ${attachment.path} omitted: size ${buf.length} bytes]`,
           });
         }
       } catch {
@@ -17938,7 +17953,7 @@ export function createAgentChatService(args: {
         }
       }
 
-      const promptBlocks = buildAgentPromptBlocks(composed, args.resolvedAttachments);
+      const promptBlocks = await buildAgentPromptBlocks(composed, args.resolvedAttachments);
       const promptText = promptBlocks
         .filter((block): block is { type: "text"; text: string } => block.type === "text")
         .map((block) => block.text)
@@ -18280,7 +18295,7 @@ export function createAgentChatService(args: {
         cloudComposed = `${injected}\n\n${cloudComposed}`;
       }
     }
-    const promptBlocks = buildAgentPromptBlocks(cloudComposed, args.resolvedAttachments);
+    const promptBlocks = await buildAgentPromptBlocks(cloudComposed, args.resolvedAttachments);
     const promptText = promptBlocks
       .filter((block): block is { type: "text"; text: string } => block.type === "text")
       .map((block) => block.text)
@@ -19095,7 +19110,7 @@ export function createAgentChatService(args: {
         "## User Request",
         composed,
       ].join("\n");
-      const promptBlocks = buildAgentPromptBlocks(sdkInput, args.resolvedAttachments);
+      const promptBlocks = await buildAgentPromptBlocks(sdkInput, args.resolvedAttachments);
       const sdkPromptText = promptBlocks
         .filter((block): block is { type: "text"; text: string } => block.type === "text")
         .map((block) => block.text)
@@ -19839,7 +19854,7 @@ export function createAgentChatService(args: {
           input.push({ type: "image", url: attachment.url });
           continue;
         }
-        const stagedPath = stageAttachmentForCodexInput(attachment);
+        const stagedPath = await stageAttachmentForCodexInput(attachment);
         if (attachment.type === "image") {
           input.push({ type: "localImage", path: stagedPath });
           continue;
@@ -20038,10 +20053,11 @@ export function createAgentChatService(args: {
       const dispatchUuid = randomUUID();
       const contextPrompt = buildChatContextAttachmentPrompt(steer.contextAttachments);
       const inlineSteerText = contextPrompt ? `${contextPrompt}\n\n${steer.text}` : steer.text;
-      const sdkMsg = buildClaudeV2Message(inlineSteerText, steer.resolvedAttachments, {
+      const sdkMsg = await buildClaudeV2MessageAsync(inlineSteerText, steer.resolvedAttachments, {
         baseDir: managed.laneWorktreePath,
         sessionId: runtime.sdkSessionId ?? null,
         forceUserMessage: true,
+        getDirtyFileTextForPath,
       }) as unknown as SDKUserMessage;
       sdkMsg.shouldQuery = false;
       sdkMsg.uuid = dispatchUuid;