Allow reads from the OS temp directory

.github/skills/coc-knowledge/references/rest-api.md

@@ -45,7 +45,7 @@ CoC server exposes HTTP endpoints organized by domain. All routes are registered
 |--------|------|-------------|
 | GET | `/api/fs/browse` | Browse local directories for repo path selection |
 | GET | `/api/fs/browse-helper` | Same-origin helper page for container-mode directory browsing |
-| GET | `/api/fs/blob?path=<absolute>` | Read a single file when the absolute path is under CoC trusted data directories or inside any registered workspace/repo root; rejects arbitrary filesystem paths |
+| GET | `/api/fs/blob?path=<absolute>` | Read a single file when the absolute path is under CoC trusted data directories (`~/.copilot`, the server data dir, or the OS temp dir) or inside any registered workspace/repo root; rejects arbitrary filesystem paths |
 
 ## Git
 

packages/coc/src/server/tasks/tasks-handler-utils.ts

@@ -14,6 +14,9 @@ import type { TasksViewerSettings, TaskFolder } from '@plusplusoneplusplus/forge
  */
 export const TRUSTED_READ_ONLY_DIRS: string[] = [
     path.join(os.homedir(), '.copilot'),
+    // The OS temp directory holds tool-output and other transient files the
+    // dashboard needs to read back (e.g. copilot-tool-output-*.txt).
+    os.tmpdir(),
 ];
 
 /** Return true when `target` is inside any of the trusted read-only directories or the server data directory. */

packages/coc/test/server/api-fs-blob.test.ts

@@ -91,14 +91,29 @@ describe('GET /api/fs/blob', () => {
 
     it('returns 403 for paths outside trusted directories', async () => {
         await startServer();
-        const outsidePath = path.join(os.tmpdir(), 'not-trusted.txt');
+        // Use a directory under the home folder (but not ~/.copilot) so it is
+        // genuinely outside all trusted roots, including the OS temp dir.
+        const outsideDir = path.join(os.homedir(), '_test_fs_blob_untrusted_' + Date.now());
+        fs.mkdirSync(outsideDir, { recursive: true });
+        cleanupDirs.push(outsideDir);
+        const outsidePath = path.join(outsideDir, 'not-trusted.txt');
         fs.writeFileSync(outsidePath, 'secret');
+        const { status, body } = await apiGet(`/api/fs/blob?path=${encodeURIComponent(outsidePath)}`);
+        expect(status).toBe(403);
+        expect(body.error).toContain('outside trusted directories');
+    });
+
+    it('accepts paths within the OS temp directory', async () => {
+        await startServer();
+        const filePath = path.join(os.tmpdir(), 'copilot-tool-output-' + Date.now() + '.txt');
+        fs.writeFileSync(filePath, 'tool output');
         try {
-            const { status, body } = await apiGet(`/api/fs/blob?path=${encodeURIComponent(outsidePath)}`);
-            expect(status).toBe(403);
-            expect(body.error).toContain('outside trusted directories');
+            const { status, body } = await apiGet(`/api/fs/blob?path=${encodeURIComponent(filePath)}`);
+            expect(status).toBe(200);
+            expect(body.content).toBe('tool output');
+            expect(body.encoding).toBe('utf-8');
         } finally {
-            fs.unlinkSync(outsidePath);
+            fs.unlinkSync(filePath);
         }
     });
 
@@ -175,7 +190,9 @@ describe('GET /api/fs/blob', () => {
     });
 
     it('rejects sibling paths outside registered workspaces', async () => {
-        const parentDir = fs.mkdtempSync(path.join(os.tmpdir(), '_test_fs_blob_parent_'));
+        // Place the workspace under the home folder (not the OS temp dir, which
+        // is now trusted) so the sibling is genuinely outside all trusted roots.
+        const parentDir = fs.mkdtempSync(path.join(os.homedir(), '_test_fs_blob_parent_'));
         cleanupDirs.push(parentDir);
         const repoDir = path.join(parentDir, 'repo');
         const siblingDir = path.join(parentDir, 'repo-sibling');

packages/coc/test/server/image-preview-api.test.ts

@@ -277,7 +277,8 @@ describe('Image Preview API', () => {
             const srv = await startServer();
             await registerWorkspace(srv, workspaceDir);
 
-            const outsideDir = fs.mkdtempSync(path.join(os.tmpdir(), 'outside-'));
+            // Use home dir (not ~/.copilot, not os.tmpdir) — genuinely outside all trusted roots.
+            const outsideDir = fs.mkdtempSync(path.join(os.homedir(), '_test_img_outside_'));
             const outsidePath = path.join(outsideDir, 'secret.svg');
             fs.writeFileSync(outsidePath, '<svg></svg>');
 

packages/coc/test/server/tasks-handler.test.ts

@@ -372,7 +372,8 @@ describe('Tasks Handler', () => {
 
         it('should reject paths outside workspace and task root', async () => {
             const srv = await startServer();
-            const evilDir = fs.mkdtempSync(path.join(os.tmpdir(), 'evil-'));
+            // Use home dir (not ~/.copilot, not os.tmpdir) — genuinely outside all trusted roots.
+            const evilDir = fs.mkdtempSync(path.join(os.homedir(), '_test_tasks_evil_'));
             fs.writeFileSync(path.join(evilDir, 'secret.txt'), 'secret', 'utf-8');
             try {
                 const wsId = await registerWorkspace(srv, workspaceDir);