feat(mcp): OAuth 2.1 and static Bearer header auth for remote MCP servers#1937
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feat(mcp): OAuth 2.1 and static Bearer header auth for remote MCP servers#1937
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Adds two authentication modes for HTTP MCP servers:
- Static headers: arbitrary headers (e.g. Authorization: Bearer ${KEY})
with vault reference resolution for embedded ${VAR} patterns
- OAuth 2.1 with PKCE: full authorization code flow with local callback
server, VaultCredentialStore for token persistence across sessions,
InMemoryStateStore for PKCE verifier/CSRF, and proactive token refresh
OAuth flow: pre-binds TcpListener before client registration to resolve
redirect_uri port, validates all discovered metadata endpoints via SSRF
guard, reads buffered HTTP until CRLF to handle TCP fragmentation.
Two-phase MCP startup: non-OAuth servers connect concurrently (phase 1),
OAuth servers connect after (phase 2) to avoid blocking startup.
Auth URL delivery: CLI via eprintln, TUI via status_tx spinner, Telegram
via stderr (follow-up: #TODO for native bot message).
New config fields on McpServerConfig: headers (HashMap<String, String>)
and oauth (McpOAuthConfig with enabled, token_storage, callback_port).
Config validation enforces mutual exclusion of headers + oauth.enabled.
Closes #1930
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Summary
Resolves #1930 — adds authentication support for remote MCP HTTP servers:
Bearer ${TOKEN}patterns127.0.0.1:18766),VaultCredentialStorebacked by age vault for token persistence across sessions, and proactive token refreshKey design decisions
TcpListenerbeforeregister_client()to resolve redirect_uri port (avoids chicken-and-egg)\r\n\r\nto handle packet fragmentationconnect_all(): non-OAuth servers concurrent (phase 1), OAuth deferred (phase 2)headersandoauth.enabledare mutually exclusive per server (validated at config load)mcp.oauth.{server_id}.{access_token,refresh_token,expires_at}New config
Known limitations
StoredCredentialstoken zeroization is an upstream rmcp limitation (accepted risk, vault at-rest encrypted)Test plan
cargo nextest run --workspace --features full --lib --bins)cargo +nightly fmt --checkcleancargo clippy --workspace --features full -- -D warningscleanMcpOAuthConfigdeserialization,OAuthTokenStorageserde,Config::validate()mutual exclusion, vault key collision detection,validate_oauth_metadata_urls()SSRF fan-out