fix(mcp): stop reporting false OAuth success when no token was obtained (#34807)

* docs(code-execution): document HERMES_* env narrowing + passthrough workaround

The execute_code sandbox-child env scrub (108397726, #27303) deliberately
dropped the broad HERMES_ prefix passthrough, keeping only an operational
4-var allowlist (HERMES_HOME/PROFILE/CONFIG/ENV). A script that relied on a
non-secret HERMES_* var (HERMES_BASE_URL, HERMES_KANBAN_DB, HERMES_*_WEBHOOK,
or a plugin-defined one) now sees it unset in the child.

Document the behavior change and the two recovery routes (terminal.env_passthrough
in config.yaml, or required_environment_variables in skill frontmatter), plus
the debug log line that surfaces the drop for diagnosis.

* fix(mcp): stop reporting false OAuth success when no token was obtained

`hermes mcp login` reported "Authenticated — N tool(s) available" for
servers that serve tools/list without auth (e.g. Google's official Drive
MCP server) even when the OAuth flow never completed — dynamic client
registration 400'd because the provider doesn't support RFC 7591, so no
token was ever acquired. Every real tool call then hung until timeout
with no indication of why.

Login now verifies a token actually landed on disk after the probe. When
it didn't, it warns that authentication didn't complete and shows the
config needed to supply a pre-registered client_id/client_secret (the
existing, already-supported workaround for DCR-less providers).

Adds a docs pitfall for Google Drive / Atlassian-style providers.

Fixes #34775

hermes_cli/mcp_config.py

@@ -205,6 +205,22 @@ def _probe_single_server(
     return tools_found
 
 
+def _oauth_tokens_present(name: str) -> bool:
+    """Return True if an OAuth token file exists on disk for ``name``.
+
+    Used after ``hermes mcp login`` to distinguish a genuine authentication
+    from a probe that succeeded only because the server allowed
+    initialize/tools-list without auth (so no token was ever acquired).
+    """
+    try:
+        from tools.mcp_oauth import HermesTokenStorage
+        return HermesTokenStorage(name).has_cached_tokens()
+    except Exception as exc:  # pragma: no cover — defensive
+        logger.debug("Could not check OAuth tokens for '%s': %s", name, exc)
+        # Be permissive on unexpected errors: don't block a real success.
+        return True
+
+
 def _unwrap_exception_group(exc: BaseException) -> Exception:
     """Extract the root-cause exception from anyio TaskGroup wrappers.
 
@@ -631,6 +647,36 @@ def cmd_mcp_login(args):
     # Probe triggers the OAuth flow (browser redirect + callback capture).
     try:
         tools = _probe_single_server(name, server_config)
+        # A clean probe is NOT proof of authentication. Some MCP servers
+        # (notably Google's official Drive server) serve initialize +
+        # tools/list WITHOUT auth, so the probe lists tools even when the
+        # OAuth flow never completed — e.g. dynamic client registration
+        # 400'd because the provider doesn't support RFC 7591. Reporting
+        # "Authenticated — N tools" in that case is a false success: every
+        # real tool call later hangs until timeout because there's no token.
+        # Verify a token actually landed on disk before claiming success.
+        if not _oauth_tokens_present(name):
+            _warning(
+                "Server responded, but no OAuth token was obtained — "
+                "authentication did not complete."
+            )
+            print()
+            _info(
+                "Some providers (e.g. Google Drive, Atlassian) do not support "
+                "automatic client registration. For those you must create an "
+                "OAuth client yourself and add its credentials to config.yaml:"
+            )
+            print()
+            print(color(f"    mcp_servers:", Colors.DIM))
+            print(color(f"      {name}:", Colors.DIM))
+            print(color(f"        url: {url}", Colors.DIM))
+            print(color(f"        auth: oauth", Colors.DIM))
+            print(color(f"        oauth:", Colors.DIM))
+            print(color(f"          client_id: \"<your-oauth-client-id>\"", Colors.DIM))
+            print(color(f"          client_secret: \"<your-oauth-client-secret>\"", Colors.DIM))
+            print()
+            _info("Then re-run `hermes mcp login " + name + "`.")
+            return
         if tools:
             _success(f"Authenticated — {len(tools)} tool(s) available")
         else: