diff --git a/apps/trip-cluster/app/__init__.py b/apps/trip-cluster/app/__init__.py
index e69de29..08f3fa3 100644
--- a/apps/trip-cluster/app/__init__.py
+++ b/apps/trip-cluster/app/__init__.py
@@ -0,0 +1,21 @@
+from flask import Flask
+
+from app.config import load_config
+from photoflow.ui import register_shared_ui
+
+
+def create_app(config=None) -> Flask:
+    app = Flask(__name__)
+    cfg = config or load_config()
+    app.config["APP_CONFIG"] = cfg
+    app.config["DATA_DIR"] = cfg.data_dir
+
+    register_shared_ui(app)
+
+    from app.routes.nav import bp as nav_bp
+    from app.routes.review import bp as review_bp
+    from app.routes.proxy import bp as proxy_bp
+    app.register_blueprint(nav_bp)
+    app.register_blueprint(review_bp)
+    app.register_blueprint(proxy_bp)
+    return app
diff --git a/apps/trip-cluster/app/cli.py b/apps/trip-cluster/app/cli.py
new file mode 100644
index 0000000..f81c172
--- /dev/null
+++ b/apps/trip-cluster/app/cli.py
@@ -0,0 +1,60 @@
+import argparse
+import sys
+
+from app.config import load_config
+
+
+def _store(cfg):
+    import os
+    from photoflow.core import Store
+    os.makedirs(cfg.data_dir, exist_ok=True)
+    return Store(cfg.db_path).connect()
+
+
+def _immich(deps, cfg):
+    if "immich" in deps:
+        return deps["immich"]
+    from photoflow.immich import ImmichClient
+    return ImmichClient(cfg.immich_url, cfg.immich_api_key)
+
+
+def cmd_serve(deps) -> int:
+    from app import create_app
+    create_app(deps["config"]).run(host="0.0.0.0", port=8084)
+    return 0
+
+
+def build_parser() -> argparse.ArgumentParser:
+    p = argparse.ArgumentParser(prog="categorize")
+    sub = p.add_subparsers(dest="command", required=True)
+
+    ing = sub.add_parser("ingest")
+    ing.add_argument("--from", dest="date_from")
+    ing.add_argument("--to", dest="date_to")
+    ing.add_argument("--tag")
+    ing.add_argument("--subset", type=int)
+    ing.add_argument("--full", action="store_true", help="ignore incremental updatedAfter")
+
+    cl = sub.add_parser("cluster")
+    cl.add_argument("--gap-factor", type=float, default=6.0)
+
+    sub.add_parser("serve")
+
+    ap = sub.add_parser("apply")
+    ap.add_argument("--yes", action="store_true", help="skip the confirmation prompt")
+
+    return p
+
+
+def main(argv=None) -> int:
+    args = build_parser().parse_args(argv)
+    deps = {"config": load_config()}
+    if args.command == "serve":
+        return cmd_serve(deps)
+    # ingest / cluster / apply are wired in later tasks.
+    print(f"Command '{args.command}' is not implemented yet.")
+    return 1
+
+
+if __name__ == "__main__":
+    sys.exit(main())
diff --git a/apps/trip-cluster/app/config.py b/apps/trip-cluster/app/config.py
new file mode 100644
index 0000000..452504c
--- /dev/null
+++ b/apps/trip-cluster/app/config.py
@@ -0,0 +1,41 @@
+import os
+from dataclasses import dataclass
+from typing import Mapping, Optional
+
+REQUIRED = ["IMMICH_URL", "IMMICH_API_KEY"]
+
+
+class ConfigError(Exception):
+    def __init__(self, missing: list):
+        self.missing = missing
+        super().__init__(f"Missing required environment variables: {', '.join(missing)}")
+
+
+@dataclass
+class Config:
+    immich_url: str
+    immich_api_key: str
+    anthropic_api_key: str
+    data_dir: str
+
+    @property
+    def db_path(self) -> str:
+        return os.path.join(self.data_dir, "trip-cluster.db")
+
+    @property
+    def thumbs_dir(self) -> str:
+        return os.path.join(self.data_dir, "thumbs")
+
+
+def load_config(env: Optional[Mapping] = None) -> Config:
+    env = env if env is not None else os.environ
+    missing = [k for k in REQUIRED if not (env.get(k) or "").strip()]
+    if missing:
+        raise ConfigError(missing)
+    data_dir = (env.get("DATA_DIR") or "").strip() or os.path.join(os.getcwd(), "data")
+    return Config(
+        immich_url=env["IMMICH_URL"].strip().rstrip("/"),
+        immich_api_key=env["IMMICH_API_KEY"].strip(),
+        anthropic_api_key=(env.get("ANTHROPIC_API_KEY") or "").strip(),
+        data_dir=data_dir,
+    )
diff --git a/apps/trip-cluster/app/routes/__init__.py b/apps/trip-cluster/app/routes/__init__.py
new file mode 100644
index 0000000..e69de29
diff --git a/apps/trip-cluster/app/routes/nav.py b/apps/trip-cluster/app/routes/nav.py
new file mode 100644
index 0000000..2245db8
--- /dev/null
+++ b/apps/trip-cluster/app/routes/nav.py
@@ -0,0 +1,13 @@
+from flask import Blueprint
+
+bp = Blueprint("nav", __name__)
+
+
+@bp.route("/health")
+def health():
+    return "ok"
+
+
+@bp.route("/")
+def index():
+    return "trip-cluster"
diff --git a/apps/trip-cluster/app/routes/proxy.py b/apps/trip-cluster/app/routes/proxy.py
new file mode 100644
index 0000000..302e85c
--- /dev/null
+++ b/apps/trip-cluster/app/routes/proxy.py
@@ -0,0 +1,14 @@
+import os
+from flask import Blueprint, current_app, send_file, abort
+
+bp = Blueprint("proxy", __name__)
+
+
+@bp.route("/thumb/<asset_id>")
+def thumb(asset_id):
+    cfg = current_app.config["APP_CONFIG"]
+    safe = os.path.basename(asset_id)
+    path = os.path.join(cfg.thumbs_dir, f"{safe}.jpg")
+    if not os.path.exists(path):
+        abort(404)
+    return send_file(path, mimetype="image/jpeg")
diff --git a/apps/trip-cluster/app/routes/review.py b/apps/trip-cluster/app/routes/review.py
new file mode 100644
index 0000000..de13b75
--- /dev/null
+++ b/apps/trip-cluster/app/routes/review.py
@@ -0,0 +1,3 @@
+from flask import Blueprint
+
+bp = Blueprint("review", __name__)
diff --git a/apps/trip-cluster/tests/test_config.py b/apps/trip-cluster/tests/test_config.py
new file mode 100644
index 0000000..523280e
--- /dev/null
+++ b/apps/trip-cluster/tests/test_config.py
@@ -0,0 +1,18 @@
+import os
+import pytest
+from app.config import load_config, ConfigError
+
+
+def test_missing_required_raises():
+    with pytest.raises(ConfigError) as e:
+        load_config({"IMMICH_URL": "http://x"})
+    assert "IMMICH_API_KEY" in e.value.missing
+
+
+def test_anthropic_optional_and_paths(tmp_path):
+    cfg = load_config({"IMMICH_URL": "http://x/", "IMMICH_API_KEY": "k",
+                       "DATA_DIR": str(tmp_path)})
+    assert cfg.immich_url == "http://x"          # trailing slash stripped
+    assert cfg.anthropic_api_key == ""           # optional in M1
+    assert cfg.db_path == os.path.join(str(tmp_path), "trip-cluster.db")
+    assert cfg.thumbs_dir == os.path.join(str(tmp_path), "thumbs")
diff --git a/apps/trip-cluster/tests/test_routes.py b/apps/trip-cluster/tests/test_routes.py
new file mode 100644
index 0000000..18de583
--- /dev/null
+++ b/apps/trip-cluster/tests/test_routes.py
@@ -0,0 +1,26 @@
+import os
+from app import create_app
+from app.config import Config
+
+
+def _app(tmp_path):
+    cfg = Config(immich_url="http://x", immich_api_key="k",
+                 anthropic_api_key="", data_dir=str(tmp_path))
+    app = create_app(cfg)
+    app.config.update(TESTING=True)
+    return app
+
+
+def test_health(tmp_path):
+    assert _app(tmp_path).test_client().get("/health").data == b"ok"
+
+
+def test_thumb_served(tmp_path):
+    thumbs = os.path.join(str(tmp_path), "thumbs")
+    os.makedirs(thumbs, exist_ok=True)
+    with open(os.path.join(thumbs, "a.jpg"), "wb") as f:
+        f.write(b"\xff\xd8\xffjpeg")
+    client = _app(tmp_path).test_client()
+    r = client.get("/thumb/a")
+    assert r.status_code == 200 and r.mimetype == "image/jpeg"
+    assert _app(tmp_path).test_client().get("/thumb/missing").status_code == 404