fix(agent-core-v2): follow symlinks in read and media tools

.changeset/fix-read-tool-symlink.md

@@ -0,0 +1,5 @@
+---
+"@moonshot-ai/kimi-code": patch
+---
+
+Fix the web backend's file-reading tools mishandling symbolic links: Read rejected them as not regular files, and media size checks measured the link instead of its target.

packages/agent-core-v2/src/agent/media/tools/read-media.ts

@@ -329,7 +329,7 @@ export class ReadMediaFileTool implements BuiltinTool<ReadMediaFileInput> {
         };
       }
 
-      const stat = await this.fs.stat(safePath);
+      const stat = await this.fs.stat(safePath, { followSymlinks: true });
       if (stat.size === 0) {
         return { isError: true, output: `"${args.path}" is empty.` };
       }

packages/agent-core-v2/src/os/backends/node-local/tools/read.ts

@@ -280,7 +280,7 @@ export class ReadTool implements BuiltinTool<ReadInput> {
     try {
       let stat: Awaited<ReturnType<IHostFileSystem['stat']>>;
       try {
-        stat = await this.fs.stat(safePath);
+        stat = await this.fs.stat(safePath, { followSymlinks: true });
       } catch (error) {
         if (isFileNotFoundError(error)) {
           return { isError: true, output: `"${args.path}" does not exist.` };

packages/agent-core-v2/test/os/backends/node-local/tools/read.test.ts

@@ -222,6 +222,16 @@ describe('ReadTool', () => {
     });
   });
 
+  it('stats with followSymlinks so symlinked files stay readable', async () => {
+    const { fs, stat } = createSpiedFs('alpha\n');
+    const tool = new ReadTool(fs, createTestEnv(), PERMISSIVE_WORKSPACE);
+
+    const result = await execute(tool, { path: '/tmp/a.txt' });
+
+    expect(result.isError).not.toBe(true);
+    expect(stat).toHaveBeenCalledWith('/tmp/a.txt', { followSymlinks: true });
+  });
+
   it('normalizes pure CRLF files to the LF model view', async () => {
     const tool = toolWithContent('alpha\r\nbeta\r\n');