Three bugs in the new MCP OAuth 2.1 PKCE implementation:
1. CRITICAL: OAuth redirect port mismatch — build_oauth_auth() calls
_find_free_port() to register the redirect_uri, but _wait_for_callback()
calls _find_free_port() again getting a DIFFERENT port. Browser redirects
to port A, server listens on port B — callback never arrives, 120s timeout.
Fix: share the port via module-level _oauth_port variable.
2. MEDIUM: Path traversal via unsanitized server_name — HermesTokenStorage
uses server_name directly in filenames. A name like "../../.ssh/config"
writes token files outside ~/.hermes/mcp-tokens/.
Fix: sanitize server_name with the same regex pattern used elsewhere.
3. MEDIUM: Class-level auth_code/state on _CallbackHandler causes data
races if concurrent OAuth flows run. Second callback overwrites first.
Fix: factory function _make_callback_handler() returns a handler class
with a closure-scoped result dict, isolating each flow.
Add hermes mcp add/remove/list/test/configure CLI for managing MCP
server connections interactively. Discovery-first 'add' flow connects,
discovers tools, and lets users select which to enable via curses checklist.
Add OAuth 2.1 PKCE authentication for MCP HTTP servers (RFC 7636).
Supports browser-based and manual (headless) authorization, token
caching with 0600 permissions, automatic refresh. Zero external deps.
Add ${ENV_VAR} interpolation in MCP server config values, resolved
from os.environ + ~/.hermes/.env at load time.
Core OAuth module from PR #2021 by @imnotdev25. CLI and mcp_tool
wiring rewritten against current main. Closes#497, #690.
