feat(teams): per-user OAuth connect flow (Path B) broker connector (spec 074, MCP-1038)#602
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…pec 074, MCP-1038) Adds internal/teams/broker.OAuthConnector implementing Path B of the upstream token-brokering spec: a per-user authorization-code + PKCE connect flow against an upstream AS that does not support token exchange. - BuildAuthorizationURL: PKCE (S256) verifier/challenge + opaque per-user state, tracked in-memory with a TTL; requires explicit AS consent (confused-deputy avoidance, FR-011). - Complete: validates state (unknown/expired/one-time), exchanges the code via the bound verifier, stores the per-user credential encrypted with ObtainedVia=connect_flow (FR-010). - Deny: clears the pending flow, stores nothing (denied consent). - Refresh: transparent refresh_token grant, preserving a non-rotated refresh token (FR-012). Config: AuthBrokerConfig gains authorization_endpoint, required for the oauth_connect mode. TDD: PKCE URL build + uniqueness, PKCE roundtrip, invalid/expired/one-time state, token-endpoint error, denied consent stores nothing, refresh path. Reuses oauth.GenerateServerKey for the store key; server edition only. Related #1038 Co-Authored-By: Paperclip <noreply@paperclip.ing>
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…irement (spec 074, MCP-1038) Address CodexReviewer request_changes on PR #602 (ENG-9): the per-upstream auth_broker config block had no docs. Add docs/features/auth-broker.md covering all three modes (token_exchange, entra_obo, oauth_connect), every field, and the oauth_connect Path B flow. Call out that auth_broker.authorization_endpoint is required for mode oauth_connect. Cross-reference from the upstream-servers config-options table. Related #602
Co-Authored-By: Paperclip <noreply@paperclip.ing>
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✅ Gatekeeper approval — Codex review verdict: ACCEPT.
This approval is posted automatically by the MCPProxy Gatekeeper App on behalf of the Codex reviewer (verdict of record lives in the Paperclip review thread). Author≠approver satisfied; QA + CI gates enforced separately.
Auto-approved per Model B (MCP-1249).
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Add a new 'server-edition' job to unit-tests.yml that builds and tests the server edition (-tags server) on every push and PR. This catches build breaks like the one in PR #602 where a duplicate type in a server-tagged file slipped through because only release.yml (tag-only) compiled with -tags server. Related #MCP-1886
…tion collision (MCP-1038) QATester BLOCKED #602: internal/teams/broker failed `-tags server` compile — oauth_connector.go redeclared `type tokenResponse`, already declared on main in token_exchanger.go (same broker package, from MCP-1037). The two serve different endpoints (plain OAuth token vs RFC 8693 token-exchange) with different field shapes (ExpiresIn int vs int64, IssuedTokenType), so they are NOT merged: the connector's type is renamed to oauthTokenResponse and its 4 references updated. Verified: go vet -tags server ./internal/teams/broker/, go build -tags server ./..., go build ./cmd/mcpproxy, go test -race -tags server ./internal/teams/broker/... (connector tests now run + pass). Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
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Add a new 'server-edition' job to unit-tests.yml that builds and tests the server edition (-tags server) on every push and PR. This catches build breaks like the one in PR #602 where a duplicate type in a server-tagged file slipped through because only release.yml (tag-only) compiled with -tags server. Related #MCP-1886
This was referenced Jun 15, 2026
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… pkg (MCP-2455) (#679) PR #602 added internal/teams/broker/oauth_connector.go AFTER the Teams->Server Edition rename (#603) moved internal/teams/ -> internal/serveredition/. The connector landed in the stale path, in package broker, referencing CredentialStore/UpstreamCredential as same-package symbols — but those live in internal/serveredition/broker. Result: 'undefined: CredentialStore' under -tags server, breaking the Server Edition CI job on main (and therefore on every open PR after #631 added that job to PR CI). Fix: git mv the connector + its test into internal/serveredition/broker/ (no importers of the old path) and delete the now-empty internal/teams/ tree. Same package, so all refs resolve. No code changes. Verified: go build -tags server ./... (0), go build ./... (0), go test -tags server ./internal/serveredition/... (all ok). Co-authored-by: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
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…am (spec 074, MCP-1039) (#688) * feat(broker): CredentialResolver — per-user-only ordering + policy seam (spec 074, MCP-1039) Add the per-user credential resolver (T6) that selects which brokered credential to inject on a proxied request. Strict per-user-only ordering (FR-013/FR-014), with no shared or static fallback: 1. valid cached per-user credential (refreshed if near-expiry); 2. else token-exchange / Entra OBO from the stored IdP subject token; 3. else, for oauth_connect upstreams the user has not connected, an actionable NotConnectedError carrying the connect URL; 4. else ErrNoCredential. - Single-flight coalescing per (user, server) so concurrent acquisitions do not trigger duplicate upstream token flows (golang.org/x/sync). - PolicyHook seam (FR-015) evaluated per call before a credential is returned; ships with an allow-all default (no policy engine yet). - Unauthenticated callers and a disabled store are rejected up front. - Exchanger/Connector/ConnectorProvider interfaces decouple the resolver from the concrete TokenExchanger (T4) and OAuthConnector (T5); both satisfy the interfaces via compile-time assertions. TDD: each ordering branch, near-expiry refresh (token-exchange + connect), unconnected -> connect-URL error, unauthenticated reject, store-disabled, policy-denied, no-static-fallback, and single-flight under -race. Related: spec 074 (MCP-1033). Builds on T3 (#601), T4 (#600), T5 (#602), all merged to main. Co-Authored-By: Paperclip <noreply@paperclip.ing> * fix(broker): address review on CredentialResolver — singleflight ctx, double-exchange, reconnect error Review (MCP-2490 / Critic) on PR #688: - must-fix: detach the caller's context inside the single-flight closure with context.WithoutCancel. The flight runs the acquisition once for all co-pending callers; inheriting the first caller's cancellation let a single client disconnect/timeout broadcast ctx.Err() to every waiter for the same (user, server). Per-caller cancellation still applies at the policy/return layer (caller's original ctx). - advisory: collapse the per-mode acquire/refresh paths so a near-expiry token-exchange miss no longer calls Exchange twice (refresh-then-fallthrough); a single Exchange now covers both cache-miss and near-expiry. - advisory: an already-connected oauth_connect user whose refresh fails now gets an actionable reconnect error (NotConnectedError.Reason) instead of a misleading "never connected" message; the connect URL is still surfaced. - advisory: document that the Exchanger (T4) and Connector (T5) persist their results themselves, so the resolver never calls store.Put. Tests: add single-flight caller-cancellation detach, no-double-exchange on near-expiry failure, and connect-flow refresh-fail -> reconnect. Full broker suite green under -tags server -race; golangci-lint v2.5.0 clean. Co-Authored-By: Paperclip <noreply@paperclip.ing> * docs(auth-broker): document per-user credential resolution ordering (spec 074, MCP-1039) Add a "Credential resolution" section describing the resolver's strict per-user-only ordering (cached/refresh -> token-exchange/OBO -> actionable connect-URL error -> no-credential), the no-shared/static-fallback guarantee, single-flight coalescing, and the policy-decision seam. Keeps the feature doc consistent with the CredentialResolver added in this PR (review follow-up). Co-Authored-By: Paperclip <noreply@paperclip.ing> --------- Co-authored-by: Paperclip <noreply@paperclip.ing>
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Spec 074 · T5 — OAuthConnector (Path B)
Implements the per-user OAuth connect flow for upstreams whose AS does not support token exchange but does standard authorization-code OAuth. This is the connector engine + handlers; REST endpoints are T8 ([MCP-1041]).
Builds on T1 ([MCP-1034], CredentialStore #587) and T2 ([MCP-1035], auth_broker config #588), both merged.
What's added
internal/teams/broker/OAuthConnector(server edition only):BuildAuthorizationURL(userID)— generates a PKCE (S256) verifier/challenge and an opaque per-userstate, tracks the pending flow in-memory with a TTL, and returns the upstream authorize URL. Explicit AS consent + unguessable state = confused-deputy avoidance (FR-011).Complete(ctx, state, code)— validatesstate(rejects unknown / expired / already-used), exchanges the code via the bound verifier at the token endpoint, and persists the per-user credential encrypted withObtainedVia=connect_flow(FR-010). State is single-use.Deny(state, reason)— denied/failed callback clears the pending flow and stores nothing.Refresh(ctx, userID)— transparentrefresh_tokengrant; preserves a non-rotated refresh token (FR-012).Store key uses the existing
oauth.GenerateServerKey(name,url)scheme. The HTTP token-exchange pattern mirrors the mergedinternal/teams/auth/oauth_providers.go.Config
config.AuthBrokerConfiggainsauthorization_endpoint, now required whenmode: oauth_connect(the connect flow needs the upstream authorize URL).token_exchange/entra_oboare unaffected.Tests (TDD — test-first, watched RED → GREEN)
oauth_connector_test.go: PKCE URL build + per-flow uniqueness, full PKCE roundtrip (token endpoint receives a verifier whose S256 equals the advertised challenge), invalid/expired/one-timestate, token-endpoint error → nothing stored, denied consent → nothing stored, refresh path (incl. preserve-on-no-rotation and no-refresh-token error), constructor validation. Plusauth_broker_test.gofor the new config requirement.Verification
go test -tags server -race ./internal/teams/broker/ ./internal/config/✅go test -tags server ./internal/teams/...✅go build -tags server ./cmd/mcpproxy✅ andgo build ./cmd/mcpproxy(personal unaffected) ✅gofmt -lclean,go vet -tags servercleanDocs note
The whole
auth_brokerblock is still being assembled across spec-074 tasks and currently has no user-facing docs (T1/T2 merged the config block + store with godoc only; the user surface — REST/CLI — lands in T8/T9). Following that precedent, end-user docs for the connect flow belong with the surfacing tasks; the new config key carries thorough godoc here.Related #1038