The MCP SDK discovers OAuth server metadata (token_endpoint, etc.) on
demand and keeps it in memory only. Without disk persistence, a restart
with valid cached refresh tokens forces the SDK to fall back to the
guessed '{server_url}/token' path — which returns 404 on most real
providers (Notion, Atlassian, GitHub remote MCP, etc.) and triggers a
full browser re-authorization even though the refresh token is fine.
Add a .meta.json file next to the existing tokens/client_info files:
HERMES_HOME/mcp-tokens/<server>.json -- tokens (existing)
HERMES_HOME/mcp-tokens/<server>.client.json -- client info (existing)
HERMES_HOME/mcp-tokens/<server>.meta.json -- oauth metadata (new)
Changes:
- HermesTokenStorage.save_oauth_metadata / load_oauth_metadata / _meta_path
— disk layer for the discovered OAuthMetadata.
- HermesTokenStorage.remove() now also clears .meta.json so
'hermes mcp remove <name>' and the manager's remove() path clean up fully.
- HermesMCPOAuthProvider._initialize cold-restores from disk before the
existing pre-flight discovery runs. If disk has metadata we skip the
discovery HTTP round-trips entirely.
- HermesMCPOAuthProvider._prefetch_oauth_metadata now persists ASM as
soon as it's discovered, so even the first pre-flight run seeds disk.
- HermesMCPOAuthProvider._persist_oauth_metadata_if_changed() is called
at the end of async_auth_flow so metadata discovered via the SDK's
lazy 401-branch (not pre-flight) is also saved for next time.
Tests cover the storage roundtrip (save/load/missing/corrupt/remove) and
the manager provider path (cold-load restore, skip-when-in-memory,
persist-on-discover, noop-when-unchanged, end-to-end async_auth_flow).
Co-authored-by: nocturnum91 <50326054+nocturnum91@users.noreply.github.com>
