Teknium 38d8446011 feat: implement MCP OAuth 2.1 PKCE client support (#5420) ...

Implement tools/mcp_oauth.py — the OAuth adapter that mcp_tool.py's
existing auth: oauth hook has been waiting for.

Components:
- HermesTokenStorage: persists tokens + client registration to
  HERMES_HOME/mcp-tokens/<server>.json with 0o600 permissions
- Callback handler factory: per-flow isolated HTTP handlers (safe for
  concurrent OAuth flows across multiple MCP servers)
- OAuthClientProvider integration: wraps the MCP SDK's httpx.Auth
  subclass which handles discovery, DCR, PKCE, token exchange,
  refresh, and step-up auth (403 insufficient_scope) automatically
- Non-interactive detection: warns when gateway/cron environments
  try to OAuth without cached tokens
- Pre-registered client support: injects client_id/secret from config
  for servers that don't support Dynamic Client Registration (e.g. Slack)
- Path traversal protection on server names
- remove_oauth_tokens() for cleanup

Config format:
  mcp_servers:
    sentry:
      url: 'https://mcp.sentry.dev/mcp'
      auth: oauth
      oauth:                          # all optional
        client_id: '...'              # skip DCR
        client_secret: '...'          # confidential client
        scope: 'read write'           # server-provided by default

Also passes oauth config dict through from mcp_tool.py (was passing
only server_name and url before).

E2E verified: full OAuth flow (401 → discovery → DCR → authorize →
token exchange → authenticated request → tokens persisted) against
local test servers. 23 unit tests + 186 MCP suite tests pass.

2026-04-05 22:08:00 -07:00

82 KiB

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