Improve delegate (#377)

* Improve delegate

* fix stale log regexes in delegate tests and add test-coupling comments

Co-authored-by: Cursor <cursoragent@cursor.com>

---------

Co-authored-by: Cursor <cursoragent@cursor.com>

mcp/file.ts

@@ -7,7 +7,7 @@ import {
   unlinkSync,
   writeFileSync,
 } from "node:fs";
-import { dirname, resolve } from "node:path";
+import { dirname, join, resolve } from "node:path";
 import { type } from "arktype";
 import type { ShellPermission } from "../external.ts";
 import type { ToolContext } from "./server.ts";
@@ -59,6 +59,15 @@ function resolveReadPath(filePath: string): string {
     return resolved;
   }
 
+  // allow reads from Cursor's project directory (internal agent coordination files)
+  const home = process.env.HOME;
+  if (home) {
+    const cursorProjectsDir = join(home, ".cursor", "projects");
+    if (resolved.startsWith(cursorProjectsDir + "/")) {
+      return resolved;
+    }
+  }
+
   // allow reads from the repo with symlink protection.
   // threat model: a malicious PR plants symlinks (e.g. `secrets -> /etc/shadow`).
   // git materializes symlinks on linux, so after checkout the working tree contains