diff --git a/CLAUDE.md b/CLAUDE.md
index 96fb337c..332bb36f 100644
--- a/CLAUDE.md
+++ b/CLAUDE.md
@@ -338,7 +338,7 @@ The server supports three deployment modes, controlled by environment variables
 - Best for: personal instances, local development
 
 **2. Multi-User BasicAuth** (profile: `multi-user-basic`)
-- Set `ENABLE_MULTI_USER_BASIC_AUTH=true`
+- Set `MCP_DEPLOYMENT_MODE=multi_user_basic`
 - Each MCP client provides credentials via HTTP Authorization header
 - Per-request client creation from extracted credentials
 - Best for: internal deployments where users manage their own Nextcloud credentials
diff --git a/docker-compose.yml b/docker-compose.yml
index 46984db5..041da0ff 100644
--- a/docker-compose.yml
+++ b/docker-compose.yml
@@ -146,11 +146,11 @@ services:
     ports:
       - 127.0.0.1:8003:8000
     environment:
-      # Multi-user BasicAuth pass-through mode (ADR-020)
+      # Multi-user BasicAuth pass-through mode (ADR-020, ADR-022)
       - NEXTCLOUD_HOST=http://app:80
       - NEXTCLOUD_MCP_SERVER_URL=http://localhost:8003
       - NEXTCLOUD_PUBLIC_ISSUER_URL=http://localhost:8080
-      - ENABLE_MULTI_USER_BASIC_AUTH=true
+      - MCP_DEPLOYMENT_MODE=multi_user_basic
       - ENABLE_BACKGROUND_OPERATIONS=true
 
       # Token storage (required for middleware initialization).
@@ -241,8 +241,8 @@ services:
       - ENABLE_TOKEN_EXCHANGE=true
       - TOKEN_EXCHANGE_CACHE_TTL=300  # Cache exchanged tokens for 5 minutes (default)
 
-      # Login Flow v2 (ADR-022) with external IdP
-      - ENABLE_LOGIN_FLOW=true
+      # Login Flow v2 (ADR-022) with external IdP — derived from the
+      # auto-detected LOGIN_FLOW deployment mode; no separate flag needed.
       - ENABLE_DCR=true
 
       # OAuth scopes (optional - uses defaults if not specified)
@@ -275,8 +275,9 @@ services:
       #- NEXTCLOUD_MCP_SERVER_URL=https://nextcloud-mcp-dev.tail148d5.ts.net
       - NEXTCLOUD_PUBLIC_ISSUER_URL=http://localhost:8080
 
-      # Login Flow v2 (ADR-022)
-      - ENABLE_LOGIN_FLOW=true
+      # Login Flow v2 (ADR-022) — the deployment mode is the single switch;
+      # the browser-based app-password layer is derived automatically.
+      - MCP_DEPLOYMENT_MODE=login_flow
 
       # Token storage (required for app password + session persistence).
       # Source the key from .env — see env.sample. To generate a fresh key:
diff --git a/docs/ADR-020-deployment-modes-and-configuration-validation.md b/docs/ADR-020-deployment-modes-and-configuration-validation.md
index f81215c7..861bb823 100644
--- a/docs/ADR-020-deployment-modes-and-configuration-validation.md
+++ b/docs/ADR-020-deployment-modes-and-configuration-validation.md
@@ -1,9 +1,9 @@
 # ADR-020: Deployment Modes and Configuration Validation
 
-**Status:** Accepted
+**Status:** Accepted — partly superseded by ADR-022 (`oauth_single_audience` renamed to `login_flow`; the `ENABLE_MULTI_USER_BASIC_AUTH` and `ENABLE_LOGIN_FLOW` env-var aliases were removed in favour of `MCP_DEPLOYMENT_MODE` as the single source of truth)
 **Date:** 2025-12-20
 **Deciders:** Development Team
-**Related:** ADR-002 (Vector Sync), ADR-004 (Progressive Consent), ADR-019 (Multi-user BasicAuth)
+**Related:** ADR-002 (Vector Sync), ADR-004 (Progressive Consent), ADR-019 (Multi-user BasicAuth), ADR-022 (Deployment Mode Consolidation)
 
 ## Context
 
diff --git a/docs/ADR-021-configuration-consolidation.md b/docs/ADR-021-configuration-consolidation.md
index 065ff936..6298a754 100644
--- a/docs/ADR-021-configuration-consolidation.md
+++ b/docs/ADR-021-configuration-consolidation.md
@@ -1,9 +1,9 @@
 # ADR-021: Configuration Consolidation and Simplification
 
-**Status:** Accepted
+**Status:** Accepted — partly superseded by ADR-022 (`oauth_single_audience` renamed to `login_flow`; `oauth_token_exchange` removed)
 **Date:** 2025-12-21
 **Deciders:** Development Team
-**Related:** ADR-020 (Deployment Modes), ADR-002 (Vector Sync), ADR-004 (Progressive Consent)
+**Related:** ADR-020 (Deployment Modes), ADR-002 (Vector Sync), ADR-004 (Progressive Consent), ADR-022 (Deployment Mode Consolidation)
 
 ## Context
 
@@ -86,10 +86,11 @@ Add `MCP_DEPLOYMENT_MODE` environment variable to remove detection ambiguity:
 
 ```bash
 # Optional: Explicitly declare deployment mode
-MCP_DEPLOYMENT_MODE=oauth_single_audience
+MCP_DEPLOYMENT_MODE=login_flow
 
 # Valid values: single_user_basic, multi_user_basic,
 #               oauth_single_audience, oauth_token_exchange
+#               (both OAuth values removed in ADR-022 — current value: login_flow)
 ```
 
 **Detection logic**:
@@ -114,7 +115,7 @@ TOKEN_STORAGE_DB=/path/to/tokens.db
 ```bash
 # Multi-user OAuth with semantic search
 NEXTCLOUD_HOST=https://nextcloud.example.com
-MCP_DEPLOYMENT_MODE=oauth_single_audience  # Explicit (optional)
+MCP_DEPLOYMENT_MODE=login_flow  # Explicit (optional)
 ENABLE_SEMANTIC_SEARCH=true                # Auto-enables background ops
 QDRANT_URL=http://qdrant:6333
 TOKEN_ENCRYPTION_KEY=<key>
@@ -271,7 +272,7 @@ def enable_semantic_search(self) -> bool:
 - `ENABLE_SEMANTIC_SEARCH=false` → `enable_background_operations=false` (unless explicitly set)
 
 **Mode selection tests**:
-- `MCP_DEPLOYMENT_MODE=oauth_single_audience` → mode correctly detected
+- `MCP_DEPLOYMENT_MODE=login_flow` → mode correctly detected
 - `MCP_DEPLOYMENT_MODE` conflicts with detected mode → validation error
 - No `MCP_DEPLOYMENT_MODE` → auto-detection works as before
 
@@ -363,7 +364,7 @@ QDRANT_URL=http://qdrant:6333
 **After** (simplified):
 ```bash
 NEXTCLOUD_HOST=https://nextcloud.example.com
-MCP_DEPLOYMENT_MODE=oauth_single_audience  # Explicit (optional)
+MCP_DEPLOYMENT_MODE=login_flow  # Explicit (optional)
 ENABLE_SEMANTIC_SEARCH=true                # Auto-enables background operations
 TOKEN_ENCRYPTION_KEY=<key>
 TOKEN_STORAGE_DB=/path/to/tokens.db
@@ -384,7 +385,7 @@ TOKEN_STORAGE_DB=/path/to/tokens.db
 **After** (optional migration):
 ```bash
 NEXTCLOUD_HOST=https://nextcloud.example.com
-MCP_DEPLOYMENT_MODE=oauth_single_audience
+MCP_DEPLOYMENT_MODE=login_flow
 ENABLE_BACKGROUND_OPERATIONS=true  # Renamed for clarity
 TOKEN_ENCRYPTION_KEY=<key>
 TOKEN_STORAGE_DB=/path/to/tokens.db
diff --git a/docs/ADR-022-deployment-mode-consolidation.md b/docs/ADR-022-deployment-mode-consolidation.md
index 9386fad6..6b958119 100644
--- a/docs/ADR-022-deployment-mode-consolidation.md
+++ b/docs/ADR-022-deployment-mode-consolidation.md
@@ -1,7 +1,7 @@
 # ADR-022: Deployment Mode Consolidation via Login Flow v2
 
-**Status:** Proposed
-**Date:** 2026-02-01
+**Status:** Accepted (step 1 — `OAUTH_SINGLE_AUDIENCE` → `LOGIN_FLOW` rename + validation gate. Dead-code pruning is a follow-up.)
+**Date:** 2026-02-01 (accepted 2026-05-12)
 **Deciders:** Development Team
 **Related:** ADR-020 (Deployment Modes), ADR-021 (Configuration Consolidation), ADR-004 (Progressive Consent), Issue #521
 
diff --git a/docs/ADR-025-dynaconf-configuration-management.md b/docs/ADR-025-dynaconf-configuration-management.md
index fd95e419..33defa6c 100644
--- a/docs/ADR-025-dynaconf-configuration-management.md
+++ b/docs/ADR-025-dynaconf-configuration-management.md
@@ -38,7 +38,7 @@ The nextcloud-mcp-server configuration system has grown to ~80+ environment vari
 |----------|-------------|---------|
 | Core Nextcloud | 6 | `NEXTCLOUD_HOST`, `NEXTCLOUD_USERNAME`, `NEXTCLOUD_VERIFY_SSL` |
 | OAuth/OIDC | 12 | `OIDC_DISCOVERY_URL`, `NEXTCLOUD_OIDC_CLIENT_ID`, `JWKS_URI` |
-| Mode Selection | 4 | `MCP_DEPLOYMENT_MODE`, `ENABLE_LOGIN_FLOW`, `ENABLE_TOKEN_EXCHANGE` |
+| Mode Selection | 1 | `MCP_DEPLOYMENT_MODE` |
 | Token Storage | 3 | `TOKEN_ENCRYPTION_KEY`, `TOKEN_STORAGE_DB` |
 | Semantic Search | 6 | `ENABLE_SEMANTIC_SEARCH`, `VECTOR_SYNC_SCAN_INTERVAL` |
 | Qdrant | 4 | `QDRANT_URL`, `QDRANT_LOCATION`, `QDRANT_API_KEY` |
@@ -108,13 +108,16 @@ nextcloud_verify_ssl = true
 nextcloud_ca_bundle = "@none"
 
 # === Deployment Mode ===
-# Auto-detected if not set. Valid: single_user_basic, multi_user_basic,
-# oauth_single_audience, login_flow, keycloak
+# Auto-detected if not set. Valid: single_user_basic, multi_user_basic, login_flow
+# (`oauth_single_audience` was renamed to `login_flow` in ADR-022; `keycloak`
+# is a planned future mode.)
 # mcp_deployment_mode = ""
 
 # === Authentication Toggles ===
-enable_multi_user_basic_auth = false
-enable_login_flow = false
+# Both `enable_multi_user_basic_auth` and `enable_login_flow` are derived
+# from MCP_DEPLOYMENT_MODE in detect_auth_mode (ADR-022 follow-up) — no
+# separate toggles. Only ENABLE_TOKEN_EXCHANGE remains as an independent
+# flag (separate cleanup).
 enable_token_exchange = false
 
 # === Token Storage ===
@@ -197,20 +200,17 @@ nextcloud_mcp_port = 8000
 # nextcloud_password = ""  (in .secrets.toml)
 
 [multi_user_basic]
-enable_multi_user_basic_auth = true
+# enable_multi_user_basic_auth is now derived from the mode (ADR-022 follow-up).
 token_storage_db = "/app/data/tokens.db"
 
 [login_flow]
-enable_login_flow = true
+# enable_login_flow is now derived from the mode (ADR-022 follow-up).
 token_storage_db = "/app/data/tokens.db"
 
 [keycloak]
 enable_token_exchange = true
 token_storage_db = "/app/data/tokens.db"
 token_exchange_cache_ttl = 300
-
-[oauth_single_audience]
-token_storage_db = "/app/data/tokens.db"
 ```
 
 **`.secrets.toml.example`** — Template, checked into git (actual `.secrets.toml` is gitignored):
@@ -265,7 +265,7 @@ Dynaconf merges configuration in this order (last wins):
 
 This means:
 - **File-based config is optional** — env vars alone still work (they override everything)
-- **Mode-specific defaults reduce boilerplate** — `[login_flow]` sets `enable_login_flow=true` and `token_storage_db=/app/data/tokens.db` so deployers don't need to
+- **Mode-specific defaults reduce boilerplate** — `[login_flow]` sets `token_storage_db=/app/data/tokens.db` so deployers don't need to
 - **Secrets are separated** — `.secrets.toml` holds `TOKEN_ENCRYPTION_KEY`, passwords, API keys
 - **Local dev overrides don't pollute** — `settings.local.toml` is gitignored
 
@@ -281,7 +281,6 @@ validators = [
     # Deployment mode validation — catch typos at startup
     Validator("MCP_DEPLOYMENT_MODE", is_in=[
         "single_user_basic", "multi_user_basic", "login_flow",
-        "keycloak", "oauth_single_audience",
     ], when=Validator("MCP_DEPLOYMENT_MODE", must_exist=True)),
 
     # Type and range validation
@@ -343,10 +342,16 @@ In **Phase 4**, this could migrate to a post-hook:
 # Phase 4 target (not implemented in Phases 1-3)
 def resolve_dependencies(settings):
     """Auto-enable background operations for semantic search in multi-user modes."""
+    mode = (settings.get("MCP_DEPLOYMENT_MODE", "") or "").lower().strip()
     is_multi_user = (
-        settings.get("ENABLE_MULTI_USER_BASIC_AUTH", False)
+        mode in {"multi_user_basic", "login_flow"}
         or settings.get("ENABLE_TOKEN_EXCHANGE", False)
-        or (not settings.get("NEXTCLOUD_USERNAME") and not settings.get("NEXTCLOUD_PASSWORD"))
+        or (
+            mode != "single_user_basic"
+            and not (
+                settings.get("NEXTCLOUD_USERNAME") and settings.get("NEXTCLOUD_PASSWORD")
+            )
+        )
     )
     if settings.get("ENABLE_SEMANTIC_SEARCH", False) and is_multi_user:
         if not settings.get("ENABLE_BACKGROUND_OPERATIONS", False):
diff --git a/docs/auth-flows.md b/docs/auth-flows.md
index 4ebf4857..7997c6f4 100644
--- a/docs/auth-flows.md
+++ b/docs/auth-flows.md
@@ -221,7 +221,7 @@ NEXTCLOUD_PASSWORD=<app-password>
 ### Multi-User BasicAuth
 ```bash
 NEXTCLOUD_HOST=https://nextcloud.example.com
-ENABLE_MULTI_USER_BASIC_AUTH=true
+MCP_DEPLOYMENT_MODE=multi_user_basic
 
 # Optional: app-password storage for background sync
 TOKEN_ENCRYPTION_KEY=<fernet-key>
@@ -231,7 +231,7 @@ TOKEN_STORAGE_DB=/app/data/tokens.db
 ### Login Flow v2
 ```bash
 NEXTCLOUD_HOST=https://nextcloud.example.com
-ENABLE_LOGIN_FLOW=true
+MCP_DEPLOYMENT_MODE=login_flow
 
 # Required for app-password storage
 TOKEN_ENCRYPTION_KEY=<fernet-key>
diff --git a/docs/authentication.md b/docs/authentication.md
index bdc826b9..25c059a9 100644
--- a/docs/authentication.md
+++ b/docs/authentication.md
@@ -43,7 +43,7 @@ Each MCP client sends its own credentials in an HTTP `Authorization: Basic` head
 
 ```bash
 NEXTCLOUD_HOST=https://your.nextcloud.example.com
-ENABLE_MULTI_USER_BASIC_AUTH=true
+MCP_DEPLOYMENT_MODE=multi_user_basic
 ```
 
 `NEXTCLOUD_USERNAME` and `NEXTCLOUD_PASSWORD` must NOT be set in this mode.
@@ -74,8 +74,8 @@ The server detects the active mode from environment variables at startup:
 | Env vars present | Detected mode |
 |------------------|---------------|
 | `NEXTCLOUD_USERNAME` + `NEXTCLOUD_PASSWORD` | Single-User (BasicAuth) |
-| `ENABLE_MULTI_USER_BASIC_AUTH=true` (no creds) | Multi-User (BasicAuth pass-through) |
-| `ENABLE_LOGIN_FLOW=true` (no creds) | Multi-User (Login Flow v2) |
+| `MCP_DEPLOYMENT_MODE=multi_user_basic` | Multi-User (BasicAuth pass-through) |
+| `MCP_DEPLOYMENT_MODE=login_flow` or no auth env vars set | Multi-User (Login Flow v2) |
 
 You can also force a mode via CLI flag:
 
diff --git a/docs/configuration-migration-v2.md b/docs/configuration-migration-v2.md
index 101c3bbf..3aac3740 100644
--- a/docs/configuration-migration-v2.md
+++ b/docs/configuration-migration-v2.md
@@ -106,7 +106,7 @@ NEXTCLOUD_USERNAME=
 NEXTCLOUD_PASSWORD=
 
 # Optional: Explicit mode declaration
-MCP_DEPLOYMENT_MODE=oauth_single_audience
+MCP_DEPLOYMENT_MODE=login_flow
 
 # One variable does it all!
 ENABLE_SEMANTIC_SEARCH=true  # Automatically enables background operations
@@ -131,7 +131,7 @@ NEXTCLOUD_OIDC_CLIENT_SECRET=secret
 **Migration Steps:**
 1. Replace `VECTOR_SYNC_ENABLED=true` with `ENABLE_SEMANTIC_SEARCH=true`
 2. Remove `ENABLE_OFFLINE_ACCESS=true` (auto-enabled)
-3. Optionally add `MCP_DEPLOYMENT_MODE=oauth_single_audience`
+3. Optionally add `MCP_DEPLOYMENT_MODE=login_flow`
 4. Restart server
 5. Check logs for confirmation: "Automatically enabled background operations for semantic search"
 
@@ -161,7 +161,7 @@ NEXTCLOUD_USERNAME=
 NEXTCLOUD_PASSWORD=
 
 # Optional: Explicit mode declaration
-MCP_DEPLOYMENT_MODE=oauth_single_audience
+MCP_DEPLOYMENT_MODE=login_flow
 
 # Renamed for clarity
 ENABLE_BACKGROUND_OPERATIONS=true  # Previously ENABLE_OFFLINE_ACCESS
@@ -178,7 +178,7 @@ NEXTCLOUD_OIDC_CLIENT_SECRET=secret
 
 **Migration Steps:**
 1. Replace `ENABLE_OFFLINE_ACCESS=true` with `ENABLE_BACKGROUND_OPERATIONS=true`
-2. Optionally add `MCP_DEPLOYMENT_MODE=oauth_single_audience`
+2. Optionally add `MCP_DEPLOYMENT_MODE=login_flow`
 3. Restart server
 
 ---
@@ -188,7 +188,7 @@ NEXTCLOUD_OIDC_CLIENT_SECRET=secret
 **Before (v0.57.x):**
 ```bash
 NEXTCLOUD_HOST=https://nextcloud.example.com
-ENABLE_MULTI_USER_BASIC_AUTH=true
+MCP_DEPLOYMENT_MODE=multi_user_basic
 
 # Both required - redundant
 ENABLE_OFFLINE_ACCESS=true
@@ -205,9 +205,6 @@ NEXTCLOUD_OIDC_CLIENT_SECRET=secret
 **After (v0.58.0+ - Simplified):**
 ```bash
 NEXTCLOUD_HOST=https://nextcloud.example.com
-ENABLE_MULTI_USER_BASIC_AUTH=true
-
-# Optional: Explicit mode declaration
 MCP_DEPLOYMENT_MODE=multi_user_basic
 
 # One variable handles both!
@@ -321,7 +318,7 @@ Only needed when you want background operations **without** semantic search:
 ```bash
 # Example: OAuth mode with background operations but NO semantic search
 NEXTCLOUD_HOST=https://nextcloud.example.com
-MCP_DEPLOYMENT_MODE=oauth_single_audience
+MCP_DEPLOYMENT_MODE=login_flow
 
 # Explicitly enable background operations for future features
 ENABLE_BACKGROUND_OPERATIONS=true
@@ -352,7 +349,7 @@ NEXTCLOUD_HOST=https://nextcloud.example.com
 # Is this OAuth or Multi-User BasicAuth? Not immediately clear.
 
 # With explicit mode:
-MCP_DEPLOYMENT_MODE=oauth_single_audience
+MCP_DEPLOYMENT_MODE=login_flow
 NEXTCLOUD_HOST=https://nextcloud.example.com
 # Clear: This is OAuth mode
 ```
@@ -363,8 +360,7 @@ NEXTCLOUD_HOST=https://nextcloud.example.com
 |-----------|-------------|
 | `single_user_basic` | Single-user with username/password |
 | `multi_user_basic` | Multi-user with BasicAuth pass-through |
-| `oauth_single_audience` | Multi-user OAuth (recommended) |
-| `oauth_token_exchange` | Multi-user OAuth with token exchange |
+| `login_flow` | Multi-user OAuth via Login Flow v2 (recommended) |
 
 ### Mode Detection Priority
 
@@ -430,7 +426,7 @@ WARNING: Both ENABLE_SEMANTIC_SEARCH and VECTOR_SYNC_ENABLED are set. Using ENAB
 
 **Symptom:**
 ```
-Error: [oauth_single_audience] TOKEN_ENCRYPTION_KEY is required when ENABLE_SEMANTIC_SEARCH is enabled
+Error: [login_flow] TOKEN_ENCRYPTION_KEY is required when ENABLE_SEMANTIC_SEARCH is enabled
 ```
 
 **Solution:**
@@ -442,13 +438,12 @@ When semantic search is enabled in multi-user modes, you need:
 ### Issue: Unexpected Mode Detected
 
 **Symptom:**
-Server activates `oauth_single_audience` mode when you expected `multi_user_basic`
+Server activates `login_flow` mode when you expected `multi_user_basic`
 
 **Solution:**
 Add explicit mode declaration:
 ```bash
 MCP_DEPLOYMENT_MODE=multi_user_basic
-ENABLE_MULTI_USER_BASIC_AUTH=true
 ```
 
 ---
@@ -483,7 +478,7 @@ docker-compose up mcp
 
 **Expected Log Output (Multi-User OAuth + Semantic Search):**
 ```
-INFO: Using explicit deployment mode: oauth_single_audience
+INFO: Using explicit deployment mode: login_flow
 INFO: Automatically enabled background operations for semantic search in multi-user mode.
 INFO: Vector sync enabled. Starting background scanner...
 ```
diff --git a/docs/configuration.md b/docs/configuration.md
index a1879596..63577c9c 100644
--- a/docs/configuration.md
+++ b/docs/configuration.md
@@ -38,12 +38,12 @@ The server supports three deployment modes. See [Authentication](authentication.
 |------|-------------|
 | `single_user_basic` | Personal use, dev — credentials in env vars |
 | `multi_user_basic` | Internal deployments — clients send credentials via `Authorization: Basic` header |
-| `login_flow_v2` | Hosted / OAuth-based MCP clients (claude.ai, Astrolabe Cloud) — recommended for multi-user |
+| `login_flow` | Hosted / OAuth-based MCP clients (claude.ai, Astrolabe Cloud) — recommended for multi-user |
 
 You can declare the mode explicitly:
 
 ```dotenv
-MCP_DEPLOYMENT_MODE=login_flow_v2
+MCP_DEPLOYMENT_MODE=login_flow
 ```
 
 If `MCP_DEPLOYMENT_MODE` is not set, the server auto-detects from the other env vars below.
@@ -74,7 +74,7 @@ Each MCP client sends its own Nextcloud credentials in an `Authorization: Basic`
 
 ```dotenv
 NEXTCLOUD_HOST=https://your.nextcloud.instance.com
-ENABLE_MULTI_USER_BASIC_AUTH=true
+MCP_DEPLOYMENT_MODE=multi_user_basic
 
 # Optional: enable per-user app-password storage for background sync
 TOKEN_ENCRYPTION_KEY=<fernet-key>
@@ -91,7 +91,7 @@ The recommended multi-user mode. MCP clients authenticate to the MCP server via
 
 ```dotenv
 NEXTCLOUD_HOST=https://your.nextcloud.instance.com
-ENABLE_LOGIN_FLOW=true
+MCP_DEPLOYMENT_MODE=login_flow
 
 # App-password storage (required)
 TOKEN_ENCRYPTION_KEY=<fernet-key>
@@ -105,7 +105,7 @@ NEXTCLOUD_PUBLIC_ISSUER_URL=https://your.nextcloud.instance.com
 | Variable | Required | Description |
 |----------|----------|-------------|
 | `NEXTCLOUD_HOST` | ✅ Yes | Internal URL of your Nextcloud instance (server-to-server) |
-| `ENABLE_LOGIN_FLOW` | ✅ Yes | Set to `true` to enable Login Flow v2 |
+| `MCP_DEPLOYMENT_MODE` | ✅ Yes | Set to `login_flow` to select this mode. The Login Flow v2 browser-app-password layer is derived from the mode automatically — no separate flag needed. |
 | `TOKEN_ENCRYPTION_KEY` | ✅ Yes | Fernet key for app-password encryption — generate with `python -c "from cryptography.fernet import Fernet; print(Fernet.generate_key().decode())"` |
 | `TOKEN_STORAGE_DB` | ✅ Yes | Path to SQLite DB for stored app passwords (use a persistent volume) |
 | `NEXTCLOUD_MCP_SERVER_URL` | ✅ Yes | Public URL of the MCP server (used as the audience claim and for browser redirects) |
@@ -197,8 +197,7 @@ OLLAMA_BASE_URL=http://ollama:11434
 **Multi-User Login Flow v2 Mode:**
 ```dotenv
 NEXTCLOUD_HOST=https://nextcloud.example.com
-MCP_DEPLOYMENT_MODE=login_flow_v2
-ENABLE_LOGIN_FLOW=true
+MCP_DEPLOYMENT_MODE=login_flow
 
 # Enable semantic search
 # In multi-user modes, this AUTOMATICALLY enables background operations!
diff --git a/docs/login-flow-v2.md b/docs/login-flow-v2.md
index 10558169..7d7e74e8 100644
--- a/docs/login-flow-v2.md
+++ b/docs/login-flow-v2.md
@@ -58,8 +58,8 @@ NEXTCLOUD_HOST=https://your.nextcloud.example.com
 NEXTCLOUD_OIDC_CLIENT_ID=<your-client-id>
 NEXTCLOUD_OIDC_CLIENT_SECRET=<your-client-secret>
 
-# Enable Login Flow v2 (per-user Nextcloud app-password provisioning for the data leg)
-ENABLE_LOGIN_FLOW=true
+# Select Login Flow v2 mode (per-user Nextcloud app-password provisioning for the data leg)
+MCP_DEPLOYMENT_MODE=login_flow
 
 # App-password storage (required for persistence across restarts)
 TOKEN_STORAGE_DB=/app/data/tokens.db
@@ -172,7 +172,7 @@ mcp-login-flow:
     - NEXTCLOUD_HOST=http://app:80
     - NEXTCLOUD_MCP_SERVER_URL=http://localhost:8004
     - NEXTCLOUD_PUBLIC_ISSUER_URL=http://localhost:8080
-    - ENABLE_LOGIN_FLOW=true
+    - MCP_DEPLOYMENT_MODE=login_flow
     # Dev-only inline value. In production, mount via Docker secret and read
     # from a *_FILE env var or a secrets-management init step.
     - TOKEN_ENCRYPTION_KEY=<your-fernet-key>
@@ -351,7 +351,7 @@ The user revoked it from **Settings → Security → Devices & Sessions**. Delet
 
 ### Multiple worker processes
 
-The provisioning session store is in-memory; `ENABLE_LOGIN_FLOW=true` assumes a single worker. Running with `uvicorn --workers N` will cause provisioning sessions to randomly fail. For higher concurrency, scale horizontally (multiple containers behind a sticky-session load balancer) rather than within a single process.
+The provisioning session store is in-memory; `MCP_DEPLOYMENT_MODE=login_flow` assumes a single worker. Running with `uvicorn --workers N` will cause provisioning sessions to randomly fail. For higher concurrency, scale horizontally (multiple containers behind a sticky-session load balancer) rather than within a single process.
 
 > **Sticky-session keying:** route on the **user identity** (e.g. the `sub` claim from the OAuth Bearer token) — **not** the raw token value, and **not** source IP. Bearer tokens rotate on refresh, which would silently break token-value affinity if a refresh lands between the request that initiates provisioning and the polling request that completes it. MCP clients may also not maintain stable IPs across those requests. A stable per-user identifier extracted from the `Authorization` header (e.g. `sub`) is the right key.
 
diff --git a/docs/running.md b/docs/running.md
index b71ad6a7..0509447a 100644
--- a/docs/running.md
+++ b/docs/running.md
@@ -336,29 +336,19 @@ messages in the container logs:
 **At server boot (all modes):**
 ```
 INFO     ✅ Configuration validated successfully for <mode> mode
+INFO     Configuring MCP server for <mode> mode
 INFO     Health check endpoints enabled: /health/live, /health/ready
 ```
 
-`<mode>` is one of `single_user_basic`, `multi_user_basic`, or
-`oauth_single`, matching the `MCP_DEPLOYMENT_MODE` setting.
-
-**Additional BasicAuth-mode messages (at server boot):**
-```
-INFO     Configuring MCP server for <mode> mode
-```
-
-Here `<mode>` is the enum value (`single_user_basic` or `multi_user_basic`).
+`<mode>` is one of `single_user_basic`, `multi_user_basic`, or `login_flow`,
+matching the `MCP_DEPLOYMENT_MODE` setting.
 
 **Additional OAuth-mode messages (at server boot):**
 ```
-INFO     Configuring MCP server for OAuth mode
 INFO     OAuth client ready: <client-id>...
 INFO     OAuth configuration complete
 ```
 
-Note the OAuth boot line logs the literal string `OAuth mode`, not the enum
-value `oauth_single`.
-
 **Additional single-user BasicAuth messages (per MCP session):**
 
 These fire when the first MCP client connects, not at server boot — if you
diff --git a/docs/troubleshooting.md b/docs/troubleshooting.md
index fd8e683a..d7e6b3a5 100644
--- a/docs/troubleshooting.md
+++ b/docs/troubleshooting.md
@@ -69,7 +69,7 @@ ENABLE_BACKGROUND_OPERATIONS=true
 
 **Symptom:**
 ```
-ValueError: Invalid MCP_DEPLOYMENT_MODE: 'oauth'. Valid values: single_user_basic, multi_user_basic, login_flow_v2
+ValueError: Invalid MCP_DEPLOYMENT_MODE: 'oauth'. Valid values: single_user_basic, multi_user_basic, login_flow
 ```
 
 **Cause:** Invalid value for `MCP_DEPLOYMENT_MODE`.
@@ -79,7 +79,7 @@ Use one of the valid mode values:
 ```bash
 MCP_DEPLOYMENT_MODE=single_user_basic   # Single-user with username/app password
 MCP_DEPLOYMENT_MODE=multi_user_basic    # Multi-user BasicAuth pass-through
-MCP_DEPLOYMENT_MODE=login_flow_v2       # Multi-user via Login Flow v2 (recommended)
+MCP_DEPLOYMENT_MODE=login_flow       # Multi-user via Login Flow v2 (recommended)
 ```
 
 Or remove `MCP_DEPLOYMENT_MODE` to use automatic detection.
@@ -90,7 +90,7 @@ Or remove `MCP_DEPLOYMENT_MODE` to use automatic detection.
 
 **Symptom:**
 ```
-Error: [login_flow_v2] TOKEN_ENCRYPTION_KEY is required when ENABLE_SEMANTIC_SEARCH is enabled
+Error: [login_flow] TOKEN_ENCRYPTION_KEY is required when ENABLE_SEMANTIC_SEARCH is enabled
 ```
 
 **Cause:** In multi-user modes, semantic search automatically enables background operations, which require encrypted token storage.
@@ -147,8 +147,8 @@ For multi-user deployment issues — provisioning loops, app-password storage, O
 
 ```bash
 # To Single-User BasicAuth: set NEXTCLOUD_USERNAME and NEXTCLOUD_PASSWORD
-# To Multi-User BasicAuth pass-through: ENABLE_MULTI_USER_BASIC_AUTH=true (no creds)
-# To Login Flow v2: ENABLE_LOGIN_FLOW=true (no creds)
+# To Multi-User BasicAuth pass-through: MCP_DEPLOYMENT_MODE=multi_user_basic (no creds)
+# To Login Flow v2: MCP_DEPLOYMENT_MODE=login_flow (no creds; also the default fallback)
 ```
 
 Restart the server after changing modes. The active mode is logged at startup; you can also set `MCP_DEPLOYMENT_MODE` explicitly to fail fast if the env vars don't match.
@@ -441,7 +441,7 @@ If problems persist, open an issue on the [GitHub repository](https://github.com
 
 - **Server logs** (with `--log-level debug`)
 - **Nextcloud version**
-- **Deployment mode** (single_user_basic / multi_user_basic / login_flow_v2)
+- **Deployment mode** (single_user_basic / multi_user_basic / login_flow)
 - **Error messages**
 - **Steps to reproduce**
 - **Environment details** (OS, Python version, Docker vs local)
diff --git a/docs/webhook-management-guide.md b/docs/webhook-management-guide.md
index 0d6dc54e..c0e55003 100644
--- a/docs/webhook-management-guide.md
+++ b/docs/webhook-management-guide.md
@@ -77,7 +77,7 @@ php occ webhook_listeners:remove <webhook-id>
 **Configuration:**
 ```bash
 NEXTCLOUD_HOST=http://nextcloud.example.com
-ENABLE_MULTI_USER_BASIC_AUTH=true
+MCP_DEPLOYMENT_MODE=multi_user_basic
 ENABLE_BACKGROUND_OPERATIONS=true
 TOKEN_ENCRYPTION_KEY=<key>
 TOKEN_STORAGE_DB=/app/data/tokens.db
diff --git a/env.sample b/env.sample
index bae9d96e..600c2ffc 100644
--- a/env.sample
+++ b/env.sample
@@ -3,11 +3,17 @@
 # ============================================
 # Optional: Explicitly declare deployment mode (ADR-021)
 # If not set, mode is auto-detected from other settings
-# Valid values: single_user_basic, multi_user_basic, oauth_single_audience,
-#               oauth_token_exchange
+# Valid values: single_user_basic, multi_user_basic, login_flow
+#
+# Note: `login_flow` is the renamed successor of the former
+# `oauth_single_audience` mode (see ADR-022). The un-augmented OAuth path
+# required unmerged Nextcloud user_oidc patches and is no longer supported.
+# Setting MCP_DEPLOYMENT_MODE=login_flow is sufficient — the Login Flow v2
+# browser-based app-password layer is derived from the mode automatically
+# (the previous ENABLE_LOGIN_FLOW=true env var has been removed).
 #
 # Recommendation: Set this for clarity and to catch configuration errors early
-#MCP_DEPLOYMENT_MODE=oauth_single_audience
+#MCP_DEPLOYMENT_MODE=login_flow
 
 # ============================================
 # COMMON SETTINGS (Required for all modes)
@@ -43,8 +49,9 @@ NEXTCLOUD_PASSWORD=
 # Users provide credentials in request headers (pass-through)
 # Use for: Multi-user without OAuth, simple shared deployments
 #
-# Required:
-#ENABLE_MULTI_USER_BASIC_AUTH=true
+# Required (sets the deployment mode; the legacy ENABLE_MULTI_USER_BASIC_AUTH
+# env var was removed in the ADR-022 follow-up):
+#MCP_DEPLOYMENT_MODE=multi_user_basic
 #
 # Optional - Background Operations (for semantic search, future features):
 # Enable background token storage using app passwords (via Astrolabe)
diff --git a/nextcloud_mcp_server/api/management.py b/nextcloud_mcp_server/api/management.py
index 0f10d6b9..b621cec2 100644
--- a/nextcloud_mcp_server/api/management.py
+++ b/nextcloud_mcp_server/api/management.py
@@ -212,7 +212,7 @@ async def get_server_status(request: Request) -> JSONResponse:
 
     # Map deployment mode to auth_mode for API response
     # This helps clients (like Astrolabe) determine which auth flow to use
-    if mode == AuthMode.OAUTH_SINGLE_AUDIENCE:
+    if mode == AuthMode.LOGIN_FLOW:
         auth_mode = "oauth"
     elif mode == AuthMode.MULTI_USER_BASIC:
         auth_mode = "multi_user_basic"
diff --git a/nextcloud_mcp_server/app.py b/nextcloud_mcp_server/app.py
index 2fa6eff9..5bdedf86 100644
--- a/nextcloud_mcp_server/app.py
+++ b/nextcloud_mcp_server/app.py
@@ -1015,8 +1015,11 @@ def get_app(transport: str = "streamable-http", enabled_apps: list[str] | None =
     logger.info(f"✅ Configuration validated successfully for {mode.value} mode")
     logger.debug(f"Mode details:\n{get_mode_summary(mode)}")
 
-    # Derive helper variables for backward compatibility with existing code
-    oauth_enabled = mode == AuthMode.OAUTH_SINGLE_AUDIENCE
+    # Derive helper variables for backward compatibility with existing code.
+    # `oauth_enabled` is True for the LOGIN_FLOW (formerly OAUTH_SINGLE_AUDIENCE)
+    # multi-user OAuth mode — in this mode the MCP server is an OIDC relying
+    # party and Login Flow v2 acquires per-user Nextcloud app passwords.
+    oauth_enabled = mode == AuthMode.LOGIN_FLOW
     # Log hybrid authentication status for multi-user BasicAuth with offline access
     if mode == AuthMode.MULTI_USER_BASIC and settings.enable_offline_access:
         logger.info(
@@ -1166,8 +1169,8 @@ def get_app(transport: str = "streamable-http", enabled_apps: list[str] | None =
                 raise
 
     # Create MCP server based on detected mode
-    if mode == AuthMode.OAUTH_SINGLE_AUDIENCE:
-        logger.info("Configuring MCP server for OAuth mode")
+    if mode == AuthMode.LOGIN_FLOW:
+        logger.info("Configuring MCP server for %s mode", mode.value)
         # Asynchronously get the OAuth configuration
 
         (
@@ -1932,7 +1935,7 @@ def get_app(transport: str = "streamable-http", enabled_apps: list[str] | None =
         # Check authentication configuration
         # Report the deployment mode, not just whether OAuth is enabled
         # This helps clients (like Astrolabe) determine which auth flow to use
-        if mode == AuthMode.OAUTH_SINGLE_AUDIENCE:
+        if mode == AuthMode.LOGIN_FLOW:
             checks["auth_mode"] = "oauth"
             checks["auth_configured"] = "ok"
         elif mode == AuthMode.MULTI_USER_BASIC:
diff --git a/nextcloud_mcp_server/config.py b/nextcloud_mcp_server/config.py
index 3a205110..62eca989 100644
--- a/nextcloud_mcp_server/config.py
+++ b/nextcloud_mcp_server/config.py
@@ -408,9 +408,10 @@ def get_document_processor_config() -> dict[str, Any]:
 class Settings:
     """Application settings from environment variables."""
 
-    # Deployment mode (ADR-021: explicit mode selection)
+    # Deployment mode (ADR-021: explicit mode selection; updated by ADR-022)
     # Optional: If not set, mode is auto-detected from other settings
-    # Valid values: single_user_basic, multi_user_basic, oauth_single_audience
+    # Valid values: single_user_basic, multi_user_basic, login_flow
+    # (ADR-022: `oauth_single_audience` was renamed to `login_flow`.)
     deployment_mode: str | None = None
 
     # OAuth/OIDC settings
@@ -452,12 +453,19 @@ class Settings:
     # Progressive Consent settings (always enabled - no flag needed)
     enable_offline_access: bool = False
 
-    # Multi-user BasicAuth pass-through mode (ADR-019 interim solution)
-    # When enabled, MCP server extracts BasicAuth credentials from request headers
-    # and passes them through to Nextcloud APIs (no storage, stateless)
+    # Multi-user BasicAuth pass-through mode (ADR-019 interim solution).
+    # Internal — not user-settable; the ENABLE_MULTI_USER_BASIC_AUTH env-var
+    # alias was removed in the ADR-022 follow-up. Auto-set by
+    # Settings.__post_init__ when MCP_DEPLOYMENT_MODE=multi_user_basic. When True,
+    # the MCP server extracts BasicAuth credentials from request headers and
+    # passes them through to Nextcloud APIs (no storage, stateless). Kept
+    # as a field for backward compat with the runtime call sites that read it.
     enable_multi_user_basic_auth: bool = False
 
-    # Login Flow v2 settings (ADR-022)
+    # Login Flow v2 derived flag (ADR-022). Internal — not user-settable.
+    # Auto-set by Settings.__post_init__ when the resolved deployment mode is
+    # LOGIN_FLOW. Kept as a field for backward compat with the runtime call
+    # sites that read it (app.py, context.py, scope_authorization.py).
     enable_login_flow: bool = False
 
     # Token and webhook storage settings
@@ -599,6 +607,57 @@ class Settings:
                 f"Smaller chunks may lose context. Consider using at least 1024 characters."
             )
 
+        # --- ADR-022 follow-up: deployment mode is the single source of truth ---
+        # The ENABLE_MULTI_USER_BASIC_AUTH and ENABLE_LOGIN_FLOW env vars were
+        # removed in favour of MCP_DEPLOYMENT_MODE. We do TWO things here:
+        #
+        # 1. Loud-fail if a user still has either legacy env var set to a
+        #    truthy value (silent removal would have flipped them into the
+        #    wrong runtime mode). Only fires for truthy strings, so an
+        #    explicit `ENABLE_LOGIN_FLOW=false` in a leftover .env passes
+        #    through harmlessly.
+        # 2. Derive `enable_login_flow` and `enable_multi_user_basic_auth`
+        #    from the resolved deployment mode here, in __post_init__, so
+        #    every Settings instance carries correct flags. (`get_settings()`
+        #    builds a fresh Settings on each call — without this, the
+        #    mutation that used to live in detect_auth_mode would only stick
+        #    on the startup Settings instance, leaving per-request handlers
+        #    with default False values.)
+        _truthy = {"1", "true", "yes", "on"}
+        for _legacy, _replacement in (
+            ("ENABLE_MULTI_USER_BASIC_AUTH", "multi_user_basic"),
+            ("ENABLE_LOGIN_FLOW", "login_flow"),
+        ):
+            if os.environ.get(_legacy, "").strip().lower() in _truthy:
+                raise ValueError(
+                    f"{_legacy} is no longer read from the environment. "
+                    f"Set MCP_DEPLOYMENT_MODE={_replacement} instead "
+                    "(ADR-022). The deployment mode is the single source "
+                    "of truth for selecting an auth flow."
+                )
+
+        # NOTE: this block mirrors the resolution logic in
+        # `config_validators.detect_auth_mode` (which works on strings via a
+        # `mode_map`). Both call sites resolve the deployment mode
+        # independently — the canonical AuthMode enum in detect_auth_mode,
+        # and the boolean derived flags here. **Keep them in sync when
+        # adding a new mode**: a new entry must be added in both places, in
+        # addition to `mode_map` (`config_validators.py`) and any
+        # MODE_REQUIREMENTS entry.
+        resolved_mode = (self.deployment_mode or "").strip().lower()
+        if not resolved_mode:
+            if self.nextcloud_username and self.nextcloud_password:
+                resolved_mode = "single_user_basic"
+            else:
+                # Default multi-user mode is Login Flow v2 (browser-based
+                # app-password acquisition); the un-augmented OAuth bearer
+                # pass-through it replaced needed unmerged Nextcloud
+                # user_oidc patches and is no longer supported.
+                resolved_mode = "login_flow"
+
+        self.enable_multi_user_basic_auth = resolved_mode == "multi_user_basic"
+        self.enable_login_flow = resolved_mode == "login_flow"
+
     def get_embedding_model_name(self) -> str:
         """
         Get the active embedding model name based on provider priority.
@@ -719,20 +778,31 @@ def _get_semantic_search_enabled() -> bool:
 def _is_multi_user_mode() -> bool:
     """Detect if this is a multi-user deployment mode.
 
+    Runs early in config setup (before Settings is fully built) for
+    mode-conditional defaults. Must match the canonical detection in
+    `config_validators.detect_auth_mode`, but works directly against the
+    raw dynaconf store since Settings doesn't exist yet.
+
     Multi-user modes are:
-    - Multi-user BasicAuth (ENABLE_MULTI_USER_BASIC_AUTH=true)
-    - OAuth Single-Audience (no username/password set)
+    - Multi-user BasicAuth (MCP_DEPLOYMENT_MODE=multi_user_basic)
+    - Login Flow v2 / default OAuth (MCP_DEPLOYMENT_MODE=login_flow, or no
+      username/password and no explicit mode)
     - OAuth Token Exchange (ENABLE_TOKEN_EXCHANGE=true)
 
-    Single-user modes are:
+    Single-user mode is:
     - Single-user BasicAuth (username and password both set)
 
     Returns:
         True if multi-user mode detected
     """
-    # Multi-user BasicAuth explicitly enabled
-    if _dynaconf.get("ENABLE_MULTI_USER_BASIC_AUTH", False):
+    # Explicit deployment mode wins. The ENABLE_MULTI_USER_BASIC_AUTH env-var
+    # alias was removed in the ADR-022 follow-up; selection is now via
+    # MCP_DEPLOYMENT_MODE.
+    explicit_mode = str(_dynaconf.get("MCP_DEPLOYMENT_MODE", "") or "").lower().strip()
+    if explicit_mode in {"multi_user_basic", "login_flow"}:
         return True
+    if explicit_mode == "single_user_basic":
+        return False
 
     # Token exchange implies OAuth multi-user
     if _dynaconf.get("ENABLE_TOKEN_EXCHANGE", False):
@@ -744,7 +814,7 @@ def _is_multi_user_mode() -> bool:
     if has_username and has_password:
         return False
 
-    # Otherwise, assume OAuth multi-user (default when no credentials provided)
+    # Otherwise, assume multi-user (default when no credentials provided)
     return True
 
 
@@ -850,10 +920,10 @@ def get_settings() -> Settings:
         "jwks_uri": "JWKS_URI",
         "introspection_uri": "INTROSPECTION_URI",
         "userinfo_uri": "USERINFO_URI",
-        # Multi-user BasicAuth pass-through mode
-        "enable_multi_user_basic_auth": "ENABLE_MULTI_USER_BASIC_AUTH",
-        # Login Flow v2 settings (ADR-022)
-        "enable_login_flow": "ENABLE_LOGIN_FLOW",
+        # NOTE: `enable_multi_user_basic_auth` and `enable_login_flow` no
+        # longer have env-var aliases — both are derived from the resolved
+        # MCP_DEPLOYMENT_MODE in detect_auth_mode() so users only configure
+        # the mode (ADR-022 follow-up).
         # Token and webhook storage settings
         "token_encryption_key": "TOKEN_ENCRYPTION_KEY",
         "token_storage_db": "TOKEN_STORAGE_DB",
diff --git a/nextcloud_mcp_server/config_validators.py b/nextcloud_mcp_server/config_validators.py
index d2e4ff8a..7434afa9 100644
--- a/nextcloud_mcp_server/config_validators.py
+++ b/nextcloud_mcp_server/config_validators.py
@@ -25,7 +25,7 @@ class AuthMode(Enum):
 
     SINGLE_USER_BASIC = "single_user_basic"
     MULTI_USER_BASIC = "multi_user_basic"
-    OAUTH_SINGLE_AUDIENCE = "oauth_single"
+    LOGIN_FLOW = "login_flow"
 
 
 @dataclass
@@ -64,7 +64,6 @@ MODE_REQUIREMENTS: dict[AuthMode, ModeRequirements] = {
             "document_chunk_overlap",
         ],
         forbidden=[
-            "enable_multi_user_basic_auth",
             "oidc_client_id",
             "oidc_client_secret",
         ],
@@ -78,7 +77,7 @@ MODE_REQUIREMENTS: dict[AuthMode, ModeRequirements] = {
         "Suitable for personal Nextcloud instances and local development.",
     ),
     AuthMode.MULTI_USER_BASIC: ModeRequirements(
-        required=["nextcloud_host", "enable_multi_user_basic_auth"],
+        required=["nextcloud_host"],
         optional=[
             # Background sync with app passwords (via Astrolabe)
             "enable_offline_access",
@@ -113,7 +112,7 @@ MODE_REQUIREMENTS: dict[AuthMode, ModeRequirements] = {
         "Users provide credentials in request headers. "
         "Optional background sync using app passwords stored via Astrolabe.",
     ),
-    AuthMode.OAUTH_SINGLE_AUDIENCE: ModeRequirements(
+    AuthMode.LOGIN_FLOW: ModeRequirements(
         required=["nextcloud_host"],
         optional=[
             # OAuth credentials (uses DCR if not provided)
@@ -138,7 +137,6 @@ MODE_REQUIREMENTS: dict[AuthMode, ModeRequirements] = {
         forbidden=[
             "nextcloud_username",
             "nextcloud_password",
-            "enable_multi_user_basic_auth",
         ],
         conditional={
             "enable_offline_access": [
@@ -149,9 +147,13 @@ MODE_REQUIREMENTS: dict[AuthMode, ModeRequirements] = {
             # enables background operations in multi-user modes. No explicit
             # enable_offline_access setting required.
         },
-        description="OAuth multi-user deployment with single-audience tokens. "
-        "Tokens work for both MCP server and Nextcloud APIs (pass-through). "
-        "Uses Dynamic Client Registration if credentials not provided.",
+        description="OAuth multi-user deployment using Login Flow v2 to acquire "
+        "per-user Nextcloud app passwords via a browser flow. The MCP server "
+        "is an OIDC relying party of a configurable IdP (Nextcloud's built-in "
+        "OIDC by default; Keycloak, AWS Cognito, etc. via OIDC_DISCOVERY_URL). "
+        "Uses Dynamic Client Registration if credentials not provided. "
+        "Replaces the deprecated direct OAuth bearer-token pass-through which "
+        "required unmerged user_oidc patches (see ADR-022).",
     ),
 }
 
@@ -159,11 +161,21 @@ MODE_REQUIREMENTS: dict[AuthMode, ModeRequirements] = {
 def detect_auth_mode(settings: Settings) -> AuthMode:
     """Detect authentication mode from configuration.
 
-    Mode detection priority (ADR-021):
-    0. Explicit MCP_DEPLOYMENT_MODE (if set) - NEW in ADR-021
-    1. Multi-user BasicAuth
-    2. Single-user BasicAuth
-    3. OAuth single-audience (default OAuth mode)
+    Mode detection priority (ADR-021, updated for ADR-022):
+    0. Explicit MCP_DEPLOYMENT_MODE (if set) — NEW in ADR-021
+    1. Multi-user BasicAuth (only via explicit mode after ADR-022 follow-up)
+    2. Single-user BasicAuth (auto-detected from credentials)
+    3. Login Flow v2 (default — was OAuth single-audience pre-ADR-022)
+
+    Pure function — the legacy-env-var deprecation and the derivation of
+    `enable_login_flow` / `enable_multi_user_basic_auth` now happen in
+    `Settings.__post_init__` so every Settings instance carries correct
+    flags regardless of how it was constructed.
+
+    Keep the resolution logic here in sync with `Settings.__post_init__`:
+    both compute the canonical mode from `deployment_mode` (+ credentials
+    as a fallback). When adding a new mode, update `mode_map` *and* the
+    `__post_init__` resolution block in `config.py`.
 
     Args:
         settings: Application settings
@@ -172,45 +184,53 @@ def detect_auth_mode(settings: Settings) -> AuthMode:
         Detected AuthMode
 
     Raises:
-        ValueError: If explicit deployment_mode is invalid or conflicts with detected mode
+        ValueError: If explicit deployment_mode is unrecognised.
     """
 
     logger = logging.getLogger(__name__)
 
-    # ADR-021: Check for explicit deployment mode first
+    # ADR-021: explicit deployment mode wins
     if settings.deployment_mode:
         mode_str = settings.deployment_mode.lower().strip()
 
-        # Map string to AuthMode enum
         mode_map = {
             "single_user_basic": AuthMode.SINGLE_USER_BASIC,
             "multi_user_basic": AuthMode.MULTI_USER_BASIC,
-            "oauth_single_audience": AuthMode.OAUTH_SINGLE_AUDIENCE,
+            "login_flow": AuthMode.LOGIN_FLOW,
         }
 
         if mode_str not in mode_map:
             valid_modes = ", ".join(mode_map.keys())
+            # ADR-022 migration hint: the most common upgrade pain is users
+            # carrying MCP_DEPLOYMENT_MODE=oauth_single_audience over from
+            # ADR-021. Surface a one-liner so they don't have to grep the
+            # changelog.
+            hint = (
+                " (Note: 'oauth_single_audience' was renamed to 'login_flow' in ADR-022.)"
+                if mode_str == "oauth_single_audience"
+                else ""
+            )
             raise ValueError(
                 f"Invalid MCP_DEPLOYMENT_MODE: '{settings.deployment_mode}'. "
-                f"Valid values: {valid_modes}"
+                f"Valid values: {valid_modes}.{hint}"
             )
 
         explicit_mode = mode_map[mode_str]
         logger.info(f"Using explicit deployment mode: {explicit_mode.value}")
         return explicit_mode
 
-    # Auto-detection (existing behavior)
-    # Check for multi-user BasicAuth
-    if settings.enable_multi_user_basic_auth:
-        return AuthMode.MULTI_USER_BASIC
+    # Auto-detection (no explicit deployment_mode).
+    # MULTI_USER_BASIC is no longer auto-detectable — the ENABLE_MULTI_USER_BASIC_AUTH
+    # env-var alias was dropped in the ADR-022 follow-up, so the only way
+    # to opt into that mode is `MCP_DEPLOYMENT_MODE=multi_user_basic`
+    # (handled above). The legacy env var fails loudly in
+    # `Settings.__post_init__`.
 
-    # Check for single-user BasicAuth (explicit credentials)
     if settings.nextcloud_username and settings.nextcloud_password:
         return AuthMode.SINGLE_USER_BASIC
 
-    # Default: OAuth single-audience mode
-    # This is the safest multi-user mode (no credential storage)
-    return AuthMode.OAUTH_SINGLE_AUDIENCE
+    # Default: Login Flow v2 multi-user mode (browser-based app-password flow).
+    return AuthMode.LOGIN_FLOW
 
 
 def validate_configuration(settings: Settings) -> tuple[AuthMode, list[str]]:
@@ -301,7 +321,14 @@ def validate_configuration(settings: Settings) -> tuple[AuthMode, list[str]]:
                 f"{settings.nextcloud_host}"
             )
 
-    if mode == AuthMode.OAUTH_SINGLE_AUDIENCE:
+    if mode == AuthMode.LOGIN_FLOW:
+        # ADR-022 follow-up: the un-augmented OAuth bearer pass-through (the
+        # old OAUTH_SINGLE_AUDIENCE without ENABLE_LOGIN_FLOW) needed unmerged
+        # Nextcloud user_oidc patches and is no longer supported. The
+        # `enable_login_flow` flag is now derived from the resolved mode in
+        # `Settings.__post_init__`, so users only configure the mode — no
+        # separate ENABLE_LOGIN_FLOW env var is needed.
+
         # If OAuth credentials not provided, DCR must be available
         # (This is a runtime check, not a config check, so we just warn)
         if not settings.oidc_client_id or not settings.oidc_client_secret:
diff --git a/nextcloud_mcp_server/vector/oauth_sync.py b/nextcloud_mcp_server/vector/oauth_sync.py
index f29443e9..7883c4db 100644
--- a/nextcloud_mcp_server/vector/oauth_sync.py
+++ b/nextcloud_mcp_server/vector/oauth_sync.py
@@ -7,7 +7,7 @@ Manages background vector sync for multi-user deployments:
 
 Authentication strategies are mutually exclusive by deployment mode:
 
-Multi-user BasicAuth mode (ENABLE_MULTI_USER_BASIC_AUTH=true):
+Multi-user BasicAuth mode (MCP_DEPLOYMENT_MODE=multi_user_basic):
 - Uses app passwords stored locally in MCP server's database
 - Users provision via Astrolabe personal settings, which sends to MCP API
 - OAuth is NOT used
diff --git a/tests/conftest.py b/tests/conftest.py
index e8aade3f..f131c7e9 100644
--- a/tests/conftest.py
+++ b/tests/conftest.py
@@ -265,7 +265,7 @@ async def nc_mcp_basic_auth_client(
 ) -> AsyncGenerator[ClientSession, Any]:
     """
     Fixture to create an MCP client session with BasicAuth credentials.
-    Connects to the multi-user BasicAuth MCP server on port 8003 with ENABLE_MULTI_USER_BASIC_AUTH=true.
+    Connects to the multi-user BasicAuth MCP server on port 8003 with MCP_DEPLOYMENT_MODE=multi_user_basic.
 
     Uses BasicAuth credentials for multi-user pass-through mode (ADR-020).
     Credentials are passed in Authorization header and forwarded to Nextcloud APIs.
diff --git a/tests/unit/test_config_validators.py b/tests/unit/test_config_validators.py
index 3aad9eaa..f7e97dec 100644
--- a/tests/unit/test_config_validators.py
+++ b/tests/unit/test_config_validators.py
@@ -10,6 +10,8 @@ Tests cover:
 import os
 from unittest.mock import patch
 
+import pytest
+
 from nextcloud_mcp_server.config import Settings, _reload_config
 from nextcloud_mcp_server.config_validators import (
     AuthMode,
@@ -23,14 +25,21 @@ class TestModeDetection:
     """Test auth mode detection from configuration."""
 
     def test_multi_user_basic_mode_detection(self):
-        """Test multi-user BasicAuth mode is detected."""
+        """Test multi-user BasicAuth mode is selected via explicit deployment_mode.
+
+        ADR-022 follow-up: the ENABLE_MULTI_USER_BASIC_AUTH auto-detection branch
+        was removed; the only way to opt in is `MCP_DEPLOYMENT_MODE=multi_user_basic`.
+        Coverage for the explicit-mode path also lives in
+        TestExplicitModeSelection::test_explicit_multi_user_basic_mode.
+        """
         settings = Settings(
             nextcloud_host="http://localhost",
-            enable_multi_user_basic_auth=True,
+            deployment_mode="multi_user_basic",
         )
 
         mode = detect_auth_mode(settings)
         assert mode == AuthMode.MULTI_USER_BASIC
+        assert settings.enable_multi_user_basic_auth is True
 
     def test_single_user_basic_mode_detection(self):
         """Test single-user BasicAuth mode is detected."""
@@ -43,14 +52,14 @@ class TestModeDetection:
         mode = detect_auth_mode(settings)
         assert mode == AuthMode.SINGLE_USER_BASIC
 
-    def test_oauth_single_audience_default(self):
-        """Test OAuth single-audience is default mode."""
+    def test_login_flow_default(self):
+        """Test Login Flow v2 is the default multi-user mode."""
         settings = Settings(
             nextcloud_host="http://localhost",
         )
 
         mode = detect_auth_mode(settings)
-        assert mode == AuthMode.OAUTH_SINGLE_AUDIENCE
+        assert mode == AuthMode.LOGIN_FLOW
 
 
 class TestSingleUserBasicValidation:
@@ -108,7 +117,7 @@ class TestSingleUserBasicValidation:
 
         # Mode detection requires BOTH username AND password for single-user BasicAuth
         # If only one is present, it defaults to OAuth single-audience
-        assert mode == AuthMode.OAUTH_SINGLE_AUDIENCE
+        assert mode == AuthMode.LOGIN_FLOW
         # In OAuth mode, having a password set is forbidden
         assert any("nextcloud_password" in err.lower() for err in errors)
 
@@ -123,24 +132,29 @@ class TestSingleUserBasicValidation:
 
         # Mode detection requires BOTH username AND password for single-user BasicAuth
         # If only one is present, it defaults to OAuth single-audience
-        assert mode == AuthMode.OAUTH_SINGLE_AUDIENCE
+        assert mode == AuthMode.LOGIN_FLOW
         # In OAuth mode, having a username set is forbidden
         assert any("nextcloud_username" in err.lower() for err in errors)
 
-    def test_forbidden_multi_user_basic_auth(self):
-        """Test error when ENABLE_MULTI_USER_BASIC_AUTH is set."""
+    def test_forbidden_multi_user_basic_when_credentials_present(self):
+        """Test multi-user mode rejects single-user credentials.
+
+        When MCP_DEPLOYMENT_MODE=multi_user_basic is set explicitly but
+        NEXTCLOUD_USERNAME/PASSWORD are also set (a misconfiguration),
+        the explicit mode wins and validation reports the credentials as
+        forbidden.
+        """
         settings = Settings(
             nextcloud_host="http://localhost",
             nextcloud_username="admin",
             nextcloud_password="password",
-            enable_multi_user_basic_auth=True,
+            deployment_mode="multi_user_basic",
         )
 
-        # Note: This will detect as MULTI_USER_BASIC due to priority
         mode, errors = validate_configuration(settings)
 
         assert mode == AuthMode.MULTI_USER_BASIC
-        # It will fail multi-user validation because username/password are forbidden
+        # Should report errors for forbidden username/password
         assert len(errors) > 0
 
     def test_vector_sync_without_embedding_provider_uses_fallback(self):
@@ -167,7 +181,7 @@ class TestMultiUserBasicValidation:
         """Test valid minimal multi-user BasicAuth config."""
         settings = Settings(
             nextcloud_host="http://localhost",
-            enable_multi_user_basic_auth=True,
+            deployment_mode="multi_user_basic",
         )
 
         mode, errors = validate_configuration(settings)
@@ -179,7 +193,7 @@ class TestMultiUserBasicValidation:
         """Test valid config with offline access enabled."""
         settings = Settings(
             nextcloud_host="http://localhost",
-            enable_multi_user_basic_auth=True,
+            deployment_mode="multi_user_basic",
             enable_offline_access=True,
             oidc_client_id="test-client",
             oidc_client_secret="test-secret",
@@ -195,7 +209,7 @@ class TestMultiUserBasicValidation:
     def test_missing_required_host(self):
         """Test error when NEXTCLOUD_HOST is missing."""
         settings = Settings(
-            enable_multi_user_basic_auth=True,
+            deployment_mode="multi_user_basic",
         )
 
         mode, errors = validate_configuration(settings)
@@ -209,13 +223,12 @@ class TestMultiUserBasicValidation:
             nextcloud_host="http://localhost",
             nextcloud_username="admin",
             nextcloud_password="password",
-            enable_multi_user_basic_auth=True,
+            deployment_mode="multi_user_basic",
         )
 
         mode, errors = validate_configuration(settings)
 
-        # Multi-user BasicAuth has higher priority than single-user in detection
-        # (explicit flags come before credentials)
+        # Explicit MCP_DEPLOYMENT_MODE wins over auto-detection from credentials
         assert mode == AuthMode.MULTI_USER_BASIC
         # Should report errors for forbidden username/password
         assert any("nextcloud_username" in err.lower() for err in errors)
@@ -225,7 +238,7 @@ class TestMultiUserBasicValidation:
         """Test that offline access works without OAuth credentials (will use DCR)."""
         settings = Settings(
             nextcloud_host="http://localhost",
-            enable_multi_user_basic_auth=True,
+            deployment_mode="multi_user_basic",
             enable_offline_access=True,
             token_encryption_key="test-key-" + "a" * 32,
             token_storage_db="/tmp/tokens.db",
@@ -241,7 +254,7 @@ class TestMultiUserBasicValidation:
         """Test error when offline access enabled but encryption key missing."""
         settings = Settings(
             nextcloud_host="http://localhost",
-            enable_multi_user_basic_auth=True,
+            deployment_mode="multi_user_basic",
             enable_offline_access=True,
             oidc_client_id="test-client",
             oidc_client_secret="test-secret",
@@ -261,7 +274,7 @@ class TestMultiUserBasicValidation:
             os.environ,
             {
                 "NEXTCLOUD_HOST": "http://localhost:8080",
-                "ENABLE_MULTI_USER_BASIC_AUTH": "true",
+                "MCP_DEPLOYMENT_MODE": "multi_user_basic",
                 "VECTOR_SYNC_ENABLED": "true",  # Using old name for backward compat test
                 "QDRANT_LOCATION": ":memory:",
                 "OLLAMA_BASE_URL": "http://ollama:11434",
@@ -285,19 +298,21 @@ class TestMultiUserBasicValidation:
             assert settings.enable_offline_access is True
 
 
-class TestOAuthSingleAudienceValidation:
-    """Test validation for OAuth single-audience mode."""
+class TestLoginFlowValidation:
+    """Test validation for Login Flow v2 mode (formerly OAUTH_SINGLE_AUDIENCE)."""
 
     def test_valid_minimal_config(self):
-        """Test valid minimal OAuth single-audience config."""
+        """Test valid minimal Login Flow v2 config — enable_login_flow is now derived."""
         settings = Settings(
             nextcloud_host="http://localhost",
         )
 
         mode, errors = validate_configuration(settings)
 
-        assert mode == AuthMode.OAUTH_SINGLE_AUDIENCE
+        assert mode == AuthMode.LOGIN_FLOW
         assert len(errors) == 0
+        # ADR-022 follow-up: enable_login_flow is derived from the resolved mode.
+        assert settings.enable_login_flow is True
 
     def test_valid_with_static_credentials(self):
         """Test valid config with static OAuth credentials."""
@@ -309,7 +324,7 @@ class TestOAuthSingleAudienceValidation:
 
         mode, errors = validate_configuration(settings)
 
-        assert mode == AuthMode.OAUTH_SINGLE_AUDIENCE
+        assert mode == AuthMode.LOGIN_FLOW
         assert len(errors) == 0
 
     def test_valid_with_offline_access(self):
@@ -325,7 +340,7 @@ class TestOAuthSingleAudienceValidation:
 
         mode, errors = validate_configuration(settings)
 
-        assert mode == AuthMode.OAUTH_SINGLE_AUDIENCE
+        assert mode == AuthMode.LOGIN_FLOW
         assert len(errors) == 0
 
     def test_forbidden_username_password(self):
@@ -351,11 +366,35 @@ class TestOAuthSingleAudienceValidation:
 
         mode, errors = validate_configuration(settings)
 
-        assert mode == AuthMode.OAUTH_SINGLE_AUDIENCE
+        assert mode == AuthMode.LOGIN_FLOW
         assert any("token_encryption_key" in err.lower() for err in errors)
 
-    def test_vector_sync_auto_enables_background_ops_in_oauth_mode(self):
-        """Test vector sync automatically enables background operations in OAuth mode (ADR-021)."""
+    def test_login_flow_mode_auto_derives_enable_login_flow_flag(self):
+        """ADR-022 follow-up: deployment_mode=login_flow auto-derives the flag.
+
+        Users no longer need to set ENABLE_LOGIN_FLOW=true (env var was
+        removed); Settings.__post_init__ populates settings.enable_login_flow
+        from the resolved mode at construction time, so every Settings
+        instance carries correct flags regardless of how it was built.
+        """
+        # Default-fallback case: no auth env vars → LOGIN_FLOW.
+        settings = Settings(nextcloud_host="http://localhost")
+        assert settings.enable_login_flow is True
+        assert settings.enable_multi_user_basic_auth is False
+        assert detect_auth_mode(settings) == AuthMode.LOGIN_FLOW
+
+        # Single-user BasicAuth (credentials set) → neither derived flag.
+        basic_settings = Settings(
+            nextcloud_host="http://localhost",
+            nextcloud_username="alice",
+            nextcloud_password="password",
+        )
+        assert basic_settings.enable_login_flow is False
+        assert basic_settings.enable_multi_user_basic_auth is False
+        assert detect_auth_mode(basic_settings) == AuthMode.SINGLE_USER_BASIC
+
+    def test_vector_sync_auto_enables_background_ops_in_login_flow_mode(self):
+        """Test vector sync automatically enables background operations in Login Flow v2 mode (ADR-021)."""
         # Before ADR-021: This would have failed validation (required explicit ENABLE_OFFLINE_ACCESS)
         # After ADR-021: vector_sync_enabled auto-enables background operations in multi-user modes
         with patch.dict(
@@ -367,7 +406,7 @@ class TestOAuthSingleAudienceValidation:
                 "OLLAMA_BASE_URL": "http://ollama:11434",
                 "TOKEN_ENCRYPTION_KEY": "test-key",
                 "TOKEN_STORAGE_DB": "/tmp/test.db",
-                # Note: No username/password = OAuth mode
+                # Note: No username/password = Login Flow v2 multi-user OAuth mode
             },
             clear=True,
         ):
@@ -377,7 +416,7 @@ class TestOAuthSingleAudienceValidation:
             settings = get_settings()
             mode, errors = validate_configuration(settings)
 
-            assert mode == AuthMode.OAUTH_SINGLE_AUDIENCE
+            assert mode == AuthMode.LOGIN_FLOW
             # Should have no errors - background operations auto-enabled
             assert len(errors) == 0
             # Verify background operations were auto-enabled
@@ -515,8 +554,8 @@ class TestConfigurationConsolidation:
             settings = get_settings()
             assert settings.enable_offline_access is True
 
-    def test_semantic_search_auto_enables_background_ops_in_oauth_mode(self):
-        """Test ENABLE_SEMANTIC_SEARCH automatically enables background operations in OAuth mode."""
+    def test_semantic_search_auto_enables_background_ops_in_login_flow_mode(self):
+        """Test ENABLE_SEMANTIC_SEARCH automatically enables background operations in Login Flow v2 mode."""
         with patch.dict(
             os.environ,
             {
@@ -634,7 +673,7 @@ class TestConfigurationConsolidation:
             os.environ,
             {
                 "NEXTCLOUD_HOST": "http://localhost:8080",
-                "ENABLE_MULTI_USER_BASIC_AUTH": "true",
+                "MCP_DEPLOYMENT_MODE": "multi_user_basic",
                 "ENABLE_SEMANTIC_SEARCH": "true",
                 "QDRANT_LOCATION": ":memory:",
                 "TOKEN_ENCRYPTION_KEY": "test-key",
@@ -707,13 +746,13 @@ class TestExplicitModeSelection:
 
             assert mode == AuthMode.MULTI_USER_BASIC
 
-    def test_explicit_oauth_single_audience_mode(self):
-        """Test explicit oauth_single_audience mode selection."""
+    def test_explicit_login_flow_mode(self):
+        """Test explicit login_flow mode selection."""
         with patch.dict(
             os.environ,
             {
                 "NEXTCLOUD_HOST": "http://localhost:8080",
-                "MCP_DEPLOYMENT_MODE": "oauth_single_audience",
+                "MCP_DEPLOYMENT_MODE": "login_flow",
             },
             clear=True,
         ):
@@ -723,7 +762,7 @@ class TestExplicitModeSelection:
             settings = get_settings()
             mode = detect_auth_mode(settings)
 
-            assert mode == AuthMode.OAUTH_SINGLE_AUDIENCE
+            assert mode == AuthMode.LOGIN_FLOW
 
     def test_invalid_deployment_mode_raises_error(self):
         """Test invalid MCP_DEPLOYMENT_MODE raises ValueError."""
@@ -749,6 +788,34 @@ class TestExplicitModeSelection:
                 assert "invalid_mode" in str(e)
                 assert "Valid values:" in str(e)
 
+    def test_oauth_single_audience_migration_hint(self):
+        """ADR-022: rejecting `oauth_single_audience` surfaces a rename hint.
+
+        Pins the special-case branch in detect_auth_mode that helps users
+        upgrading from ADR-021 configurations spot the rename without
+        having to grep the changelog.
+        """
+        with patch.dict(
+            os.environ,
+            {
+                "NEXTCLOUD_HOST": "http://localhost:8080",
+                "MCP_DEPLOYMENT_MODE": "oauth_single_audience",
+            },
+            clear=True,
+        ):
+            from nextcloud_mcp_server.config import get_settings
+
+            _reload_config()
+            settings = get_settings()
+
+            with pytest.raises(ValueError) as exc:
+                detect_auth_mode(settings)
+
+            msg = str(exc.value)
+            assert "oauth_single_audience" in msg
+            assert "login_flow" in msg
+            assert "ADR-022" in msg
+
     def test_explicit_mode_overrides_auto_detection(self):
         """Test explicit mode takes precedence over auto-detection."""
         with patch.dict(
@@ -757,7 +824,7 @@ class TestExplicitModeSelection:
                 "NEXTCLOUD_HOST": "http://localhost:8080",
                 "NEXTCLOUD_USERNAME": "admin",  # Would auto-detect as single_user_basic
                 "NEXTCLOUD_PASSWORD": "password",
-                "MCP_DEPLOYMENT_MODE": "oauth_single_audience",  # Explicit override
+                "MCP_DEPLOYMENT_MODE": "login_flow",  # Explicit override
             },
             clear=True,
         ):
@@ -768,7 +835,7 @@ class TestExplicitModeSelection:
             mode = detect_auth_mode(settings)
 
             # Should use explicit mode, not auto-detected mode
-            assert mode == AuthMode.OAUTH_SINGLE_AUDIENCE
+            assert mode == AuthMode.LOGIN_FLOW
 
     def test_case_insensitive_mode_names(self):
         """Test MCP_DEPLOYMENT_MODE is case-insensitive."""
@@ -776,7 +843,7 @@ class TestExplicitModeSelection:
             os.environ,
             {
                 "NEXTCLOUD_HOST": "http://localhost:8080",
-                "MCP_DEPLOYMENT_MODE": "OAUTH_SINGLE_AUDIENCE",  # Uppercase
+                "MCP_DEPLOYMENT_MODE": "LOGIN_FLOW",  # Uppercase
             },
             clear=True,
         ):
@@ -786,7 +853,7 @@ class TestExplicitModeSelection:
             settings = get_settings()
             mode = detect_auth_mode(settings)
 
-            assert mode == AuthMode.OAUTH_SINGLE_AUDIENCE
+            assert mode == AuthMode.LOGIN_FLOW
 
     def test_whitespace_in_mode_name_stripped(self):
         """Test whitespace in MCP_DEPLOYMENT_MODE is stripped."""
@@ -794,7 +861,7 @@ class TestExplicitModeSelection:
             os.environ,
             {
                 "NEXTCLOUD_HOST": "http://localhost:8080",
-                "MCP_DEPLOYMENT_MODE": "  oauth_single_audience  ",  # Whitespace
+                "MCP_DEPLOYMENT_MODE": "  login_flow  ",  # Whitespace
             },
             clear=True,
         ):
@@ -804,4 +871,114 @@ class TestExplicitModeSelection:
             settings = get_settings()
             mode = detect_auth_mode(settings)
 
-            assert mode == AuthMode.OAUTH_SINGLE_AUDIENCE
+            assert mode == AuthMode.LOGIN_FLOW
+
+    def test_legacy_enable_multi_user_basic_auth_env_var_errors(self):
+        """ADR-022 follow-up: ENABLE_MULTI_USER_BASIC_AUTH=true must fail loudly.
+
+        The env-var alias was removed; users must migrate to
+        `MCP_DEPLOYMENT_MODE=multi_user_basic`. Silent removal would have
+        switched users to LOGIN_FLOW (the default) — wrong runtime mode.
+        The check lives in Settings.__post_init__ so it fires at config
+        load time, not only when detect_auth_mode is reached.
+        """
+        with patch.dict(
+            os.environ,
+            {
+                "NEXTCLOUD_HOST": "http://localhost:8080",
+                "ENABLE_MULTI_USER_BASIC_AUTH": "true",
+            },
+            clear=True,
+        ):
+            from nextcloud_mcp_server.config import get_settings
+
+            _reload_config()
+
+            with pytest.raises(ValueError) as exc:
+                get_settings()
+
+            assert "ENABLE_MULTI_USER_BASIC_AUTH" in str(exc.value)
+            assert "multi_user_basic" in str(exc.value)
+
+    def test_legacy_enable_login_flow_env_var_errors(self):
+        """ADR-022 follow-up: ENABLE_LOGIN_FLOW=true must fail loudly.
+
+        Mirrors the ENABLE_MULTI_USER_BASIC_AUTH check — both legacy aliases
+        now error with a one-line migration message at Settings construction.
+        """
+        with patch.dict(
+            os.environ,
+            {
+                "NEXTCLOUD_HOST": "http://localhost:8080",
+                "ENABLE_LOGIN_FLOW": "true",
+            },
+            clear=True,
+        ):
+            from nextcloud_mcp_server.config import get_settings
+
+            _reload_config()
+
+            with pytest.raises(ValueError) as exc:
+                get_settings()
+
+            assert "ENABLE_LOGIN_FLOW" in str(exc.value)
+            assert "login_flow" in str(exc.value)
+
+    def test_legacy_env_var_check_ignores_falsy_strings(self):
+        """ADR-022 follow-up: a leftover ENABLE_LOGIN_FLOW=false must NOT error.
+
+        Reviewer round 2 found that the legacy check used `os.getenv(legacy)`
+        which is truthy for the literal string 'false'. A user who had
+        explicitly set the flag to false (meaning 'I don't want this') would
+        get a startup ValueError after upgrading, which is wrong. The fix
+        only fires for explicitly-truthy values.
+        """
+        with patch.dict(
+            os.environ,
+            {
+                "NEXTCLOUD_HOST": "http://localhost:8080",
+                "ENABLE_LOGIN_FLOW": "false",
+                "ENABLE_MULTI_USER_BASIC_AUTH": "0",
+            },
+            clear=True,
+        ):
+            from nextcloud_mcp_server.config import get_settings
+
+            _reload_config()
+            settings = get_settings()  # Must not raise.
+
+            # Falls through to LOGIN_FLOW (the auto-detect default) since
+            # no credentials are set.
+            assert detect_auth_mode(settings) == AuthMode.LOGIN_FLOW
+
+    def test_derived_flags_stable_across_get_settings_calls(self):
+        """Regression: derived flags must persist across get_settings() calls.
+
+        `get_settings()` builds a fresh Settings on each invocation. Earlier
+        commits set the derived flags as a side effect of detect_auth_mode,
+        which meant the *next* get_settings() call started with default
+        False — breaking per-request handlers in the integration tests
+        for `mcp-multi-user-basic` and `mcp-login-flow`. The fix moves the
+        derivation into Settings.__post_init__ so every instance carries
+        correct flags.
+        """
+        with patch.dict(
+            os.environ,
+            {
+                "NEXTCLOUD_HOST": "http://localhost:8080",
+                "MCP_DEPLOYMENT_MODE": "multi_user_basic",
+            },
+            clear=True,
+        ):
+            from nextcloud_mcp_server.config import get_settings
+
+            _reload_config()
+
+            s1 = get_settings()
+            s2 = get_settings()
+
+            assert s1 is not s2  # fresh instance each call
+            assert s1.enable_multi_user_basic_auth is True
+            assert s2.enable_multi_user_basic_auth is True
+            assert s1.enable_login_flow is False
+            assert s2.enable_login_flow is False
diff --git a/tests/unit/test_management_status_endpoint.py b/tests/unit/test_management_status_endpoint.py
index f6ea5f40..313a12a7 100644
--- a/tests/unit/test_management_status_endpoint.py
+++ b/tests/unit/test_management_status_endpoint.py
@@ -173,7 +173,7 @@ class TestStatusEndpointOidcConfig:
             ),
             patch(
                 "nextcloud_mcp_server.api.management.detect_auth_mode",
-                return_value=AuthMode.OAUTH_SINGLE_AUDIENCE,
+                return_value=AuthMode.LOGIN_FLOW,
             ),
         ):
             app = create_test_app()
diff --git a/tests/unit/test_stdio.py b/tests/unit/test_stdio.py
index a70053be..cd2418ae 100644
--- a/tests/unit/test_stdio.py
+++ b/tests/unit/test_stdio.py
@@ -14,8 +14,8 @@ def single_user_env(monkeypatch):
     monkeypatch.setenv("NEXTCLOUD_HOST", "https://cloud.example.com")
     monkeypatch.setenv("NEXTCLOUD_USERNAME", "admin")
     monkeypatch.setenv("NEXTCLOUD_PASSWORD", "secret")
-    # Ensure multi-user mode is off (may leak from other tests)
-    monkeypatch.delenv("ENABLE_MULTI_USER_BASIC_AUTH", raising=False)
+    # Ensure no explicit deployment mode leaks from other tests
+    monkeypatch.delenv("MCP_DEPLOYMENT_MODE", raising=False)
     _reload_config()
     yield
     _reload_config()