Print the tools TELEGRAM_EXPOSED_TOOLS hides at startup

read-only mode unregisters tools silently, so the only way to learn which
names the + allowlist accepts was reading the annotations in the source.
Print them to stderr, like the other startup messages.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

Author: XavierZhao1989

README.md

@@ -261,6 +261,9 @@ TELEGRAM_EXPOSED_TOOLS=read-only+send_message,reply_to_message,send_file
 An unknown name in the allowlist aborts startup, so a typo cannot silently
 degrade into a narrower surface that looks like it worked.
 
+At startup the server prints the names of the tools the mode hides to stderr;
+those are the names the `+` list accepts.
+
 This is an MCP tool-surface restriction, not a Telegram session sandbox or
 reduced Telegram account permission. The Telegram session string still has its
 normal authority inside the server process; read-only mode only prevents

telegram_mcp/runner.py

@@ -275,7 +275,15 @@ def main() -> None:
     # send_file is not exposed is a valid configuration, so the name check
     # has to see the full tool set.
     _runtime._apply_file_extension_overrides()
-    _runtime._apply_exposed_tools_mode()
+    hidden = _runtime._apply_exposed_tools_mode()
+    if hidden:
+        # These names are the menu for the "+" allowlist; without this line the
+        # only way to find them is reading the tool annotations in the source.
+        print(
+            f"TELEGRAM_EXPOSED_TOOLS hides {len(hidden)} tool(s); list any of them "
+            f"after '+' to expose it: {', '.join(sorted(hidden))}",
+            file=sys.stderr,
+        )
     _transcription.validate_transcription_config()
     _session_lock_shared()  # fail loudly at startup on a bad toggle
     asyncio.run(_main())

tests/test_runner.py

@@ -434,3 +434,23 @@ def test_cli_host_and_port_flags(monkeypatch):
     runtime._configure_allowed_roots_from_cli(["--host", "0.0.0.0", "--port", "9000"])
     assert runtime._CLI_HOST == "0.0.0.0"
     assert runtime._CLI_PORT == 9000
+
+
+def test_main_prints_the_tools_exposure_hides(monkeypatch, capsys):
+    """The hidden names are what a user copies into read-only+<tool>."""
+    monkeypatch.setattr(runner, "_configure_allowed_roots_from_cli", lambda *a, **k: None)
+    monkeypatch.setattr(runner._runtime, "_apply_file_extension_overrides", lambda: None)
+    monkeypatch.setattr(
+        runner._runtime,
+        "_apply_exposed_tools_mode",
+        lambda: ["send_message", "export_chat_invite"],
+    )
+    monkeypatch.setattr(runner._transcription, "validate_transcription_config", lambda: None)
+    monkeypatch.setattr(runner, "_session_lock_shared", lambda: None)
+    monkeypatch.setattr(runner.asyncio, "run", lambda coro: coro.close())
+
+    runner.main()
+
+    err = capsys.readouterr().err
+    assert "hides 2 tool(s)" in err
+    assert "export_chat_invite, send_message" in err