feat: add Tailscale Funnel config for Claude AI connector testing

Add docker compose services (tailscale-mcp + nginx-claude-filter) behind
a claude-funnel profile that expose the login-flow MCP server via
Tailscale Funnel with IP-based access control:

- /mcp endpoint restricted to Claude AI outbound IPs (160.79.104.0/21)
- /oauth/*, /.well-known/*, /app paths open to all IPs (user login flow)
- All other paths return 404

Also add favicon.png served at /favicon.ico for connector directory
discovery (Google favicon service).

Usage:
  docker compose --profile login-flow --profile claude-funnel up -d

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

claude-funnel/nginx.conf

@@ -0,0 +1,88 @@
+# Claude AI IP Filter for Tailscale Funnel
+#
+# Routes MCP transport to Claude AI IPs only, while allowing
+# OAuth/auth endpoints from any IP (needed for user login flow).
+#
+# Pattern: homelab-argocd/atlantis/templates/nginx-webhook-config.yaml
+
+worker_processes auto;
+pid /var/run/nginx.pid;
+
+events {
+    worker_connections 1024;
+}
+
+http {
+    include /etc/nginx/mime.types;
+    default_type application/octet-stream;
+
+    log_format main '$remote_addr - $remote_user [$time_local] "$request" '
+                    '$status $body_bytes_sent "$http_referer" '
+                    '"$http_user_agent" "$http_x_forwarded_for"';
+
+    access_log /var/log/nginx/access.log main;
+    error_log /var/log/nginx/error.log warn;
+
+    sendfile on;
+    keepalive_timeout 65;
+
+    # Map Claude AI outbound IPs (must be at http level)
+    geo $remote_addr $is_claude_ai {
+        default 0;
+
+        # Anthropic Claude AI Outbound IP Range
+        # Source: https://docs.claude.com/en/api/ip-addresses
+        # Last updated: 2026-03-29
+
+        # IPv4 range
+        160.79.104.0/21  1;  # Claude AI
+    }
+
+    server {
+        listen 8080;
+        server_name _;
+
+        # Trust Tailscale proxy for real IP extraction
+        real_ip_header X-Forwarded-For;
+        set_real_ip_from 100.64.0.0/10;  # Tailscale CGNAT range
+        set_real_ip_from 10.0.0.0/8;     # Docker internal networks
+        set_real_ip_from 172.16.0.0/12;  # Docker bridge networks
+        real_ip_recursive on;
+
+        # OAuth/auth endpoints + favicon - allow ALL IPs (user browser needs access for login flow)
+        location ~ ^/(oauth|\.well-known|app|favicon\.ico)(/|$) {
+            proxy_pass http://mcp-login-flow:8004;
+            proxy_set_header Host $host;
+            proxy_set_header X-Real-IP $remote_addr;
+            proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
+            proxy_set_header X-Forwarded-Proto https;
+        }
+
+        # MCP transport endpoint - Claude AI IPs ONLY
+        # login-flow uses streamable-http transport (no /sse needed)
+        location /mcp {
+            if ($is_claude_ai = 0) {
+                return 403 '{"error": "Access denied - IP not in Claude AI range", "source_ip": "$remote_addr"}\n';
+            }
+
+            proxy_pass http://mcp-login-flow:8004;
+            proxy_set_header Host $host;
+            proxy_set_header X-Real-IP $remote_addr;
+            proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
+            proxy_set_header X-Forwarded-Proto https;
+
+            # Streamable HTTP support (long-lived connections)
+            proxy_buffering off;
+            proxy_cache off;
+            proxy_read_timeout 86400s;
+            proxy_send_timeout 86400s;
+            proxy_http_version 1.1;
+            proxy_set_header Connection '';
+        }
+
+        # Default - deny everything else
+        location / {
+            return 404 '{"error": "Not found"}\n';
+        }
+    }
+}

claude-funnel/serve-config.json

@@ -0,0 +1,19 @@
+{
+  "TCP": {
+    "443": {
+      "HTTPS": true
+    }
+  },
+  "Web": {
+    "${TS_CERT_DOMAIN}:443": {
+      "Handlers": {
+        "/": {
+          "Proxy": "http://nginx-claude-filter:8080"
+        }
+      }
+    }
+  },
+  "AllowFunnel": {
+    "${TS_CERT_DOMAIN}:443": true
+  }
+}

docker-compose.yml

@@ -303,6 +303,7 @@ services:
     environment:
       - NEXTCLOUD_HOST=http://app:80
       - NEXTCLOUD_MCP_SERVER_URL=http://localhost:8004
+      #- NEXTCLOUD_MCP_SERVER_URL=https://nextcloud-mcp-dev.tail148d5.ts.net
       - NEXTCLOUD_PUBLIC_ISSUER_URL=http://localhost:8080
 
       # Login Flow v2 (ADR-022)
@@ -324,6 +325,38 @@ services:
     profiles:
       - login-flow
 
+  # Tailscale Funnel for Claude AI connector testing
+  # Usage: docker compose --profile login-flow --profile claude-funnel up --build -d
+  # Requires: TS_AUTHKEY in .env file (see env.sample.claude-funnel)
+  tailscale-mcp:
+    image: tailscale/tailscale:latest
+    hostname: nextcloud-mcp-dev
+    restart: always
+    environment:
+      - TS_AUTHKEY=${TS_AUTHKEY}
+      - TS_STATE_DIR=/var/lib/tailscale
+      - TS_SERVE_CONFIG=/config/serve-config.json
+      - TS_HOSTNAME=nextcloud-mcp-dev
+      - TS_EXTRA_ARGS=--advertise-tags=tag:container
+    volumes:
+      - tailscale-state:/var/lib/tailscale
+      - ./claude-funnel/serve-config.json:/config/serve-config.json:ro
+    cap_add:
+      - NET_ADMIN
+      - SYS_MODULE
+    profiles:
+      - claude-funnel
+
+  nginx-claude-filter:
+    image: docker.io/library/nginx:alpine
+    restart: always
+    depends_on:
+      - mcp-login-flow
+    volumes:
+      - ./claude-funnel/nginx.conf:/etc/nginx/nginx.conf:ro
+    profiles:
+      - claude-funnel
+
   qdrant:
     image: docker.io/qdrant/qdrant:v1.17.1@sha256:94728574965d17c6485dd361aa3c0818b325b9016dac5ea6afec7b4b2700865f
     restart: always
@@ -354,3 +387,4 @@ volumes:
   qdrant-data:
   mcp-data:
   multi-user-basic-data:
+  tailscale-state:

env.sample.claude-funnel

@@ -0,0 +1,22 @@
+# Claude AI Connector - Tailscale Funnel Configuration
+#
+# This profile exposes the MCP server (login-flow mode) via Tailscale Funnel
+# for testing Claude AI connector integration.
+#
+# Usage:
+#   1. Copy this file to .env and fill in TS_AUTHKEY
+#   2. Run: docker compose --profile login-flow --profile claude-funnel up --build -d
+#   3. Configure Claude.ai connector with: https://nextcloud-mcp-dev.<tailnet>.ts.net/mcp
+#
+# Prerequisites:
+#   - Generate auth key at https://login.tailscale.com/admin/settings/keys
+#     with tag:container and reusable=yes
+#   - Ensure Tailscale ACL allows funnel for tag:container:
+#     "nodeAttrs": [{ "target": ["tag:container"], "attr": ["funnel"] }]
+#
+# Security:
+#   - /mcp endpoint restricted to Claude AI IPs (160.79.104.0/21)
+#   - /oauth/* and /.well-known/* open to all IPs (needed for user login flow)
+#   - All other paths return 404
+
+TS_AUTHKEY=tskey-auth-REPLACE_ME

nextcloud_mcp_server/app.py

@@ -24,7 +24,7 @@ from pydantic import AnyHttpUrl
 from starlette.applications import Starlette
 from starlette.middleware.authentication import AuthenticationMiddleware
 from starlette.middleware.cors import CORSMiddleware
-from starlette.responses import JSONResponse, RedirectResponse
+from starlette.responses import FileResponse, JSONResponse, RedirectResponse
 from starlette.routing import Mount, Route
 from starlette.staticfiles import StaticFiles
 from starlette.types import ASGIApp, Receive, Send
@@ -2342,6 +2342,18 @@ def get_app(transport: str = "streamable-http", enabled_apps: list[str] | None =
     routes.append(Mount("/app", app=browser_app))
     logger.info("App routes with session auth: /app, /app/webhooks, /app/revoke")
 
+    # Favicon for connector directory discovery (Google favicon service)
+    favicon_path = os.path.join(
+        os.path.dirname(__file__), "auth", "static", "favicon.png"
+    )
+    if os.path.isfile(favicon_path):
+        routes.append(
+            Route(
+                "/favicon.ico",
+                lambda request: FileResponse(favicon_path, media_type="image/png"),
+            )
+        )
+
     # Mount FastMCP at root last (catch-all, handles OAuth via token_verifier)
     routes.append(Mount("/", app=mcp_app))