diff --git a/app/graph/service.py b/app/graph/service.py
new file mode 100644
index 0000000..40b430e
--- /dev/null
+++ b/app/graph/service.py
@@ -0,0 +1,172 @@
+#!/usr/bin/env python3
+# -*- coding: utf-8 -*-
+"""
+Modul: app/graph/service.py
+Version: 0.1.0
+Datum: 2025-09-10
+
+Zweck
+-----
+Leichtgewichtiger Graph-Layer über Qdrant:
+  - get_note(note_id)
+  - get_chunks(note_id)
+  - neighbors(source_id, kinds=[...], scope=['note','chunk'], depth=1)
+  - walk_bfs(source_id, kinds, max_depth)
+  - context_for_note(note_id, max_neighbors): heuristische Kontextsammlung
+
+Hinweise
+--------
+- Nutzt die bestehenden Collections <prefix>_notes/_chunks/_edges.
+- Edges werden über Payload-Felder (`kind`, `source_id`, `target_id`) abgefragt.
+"""
+from __future__ import annotations
+from typing import List, Dict, Any, Optional, Iterable, Set, Tuple
+from qdrant_client.http import models as rest
+from app.core.qdrant import QdrantConfig, get_client
+
+def _cols(prefix: str):
+    return f"{prefix}_notes", f"{prefix}_chunks", f"{prefix}_edges"
+
+class GraphService:
+    def __init__(self, cfg: Optional[QdrantConfig] = None, prefix: Optional[str] = None):
+        self.cfg = cfg or QdrantConfig.from_env()
+        if prefix:
+            self.cfg.prefix = prefix
+        self.client = get_client(self.cfg)
+        self.notes_col, self.chunks_col, self.edges_col = _cols(self.cfg.prefix)
+
+    # ------------------------ fetch helpers ------------------------
+    def _scroll(self, col: str, flt: Optional[rest.Filter] = None, limit: int = 256):
+        out = []
+        nextp = None
+        while True:
+            pts, nextp = self.client.scroll(
+                collection_name=col,
+                with_payload=True,
+                with_vectors=False,
+                limit=limit,
+                offset=nextp,
+                scroll_filter=flt,
+            )
+            if not pts:
+                break
+            out.extend(pts)
+            if nextp is None:
+                break
+        return out
+
+    # ------------------------ public API ---------------------------
+    def get_note(self, note_id: str) -> Optional[Dict[str, Any]]:
+        f = rest.Filter(must=[rest.FieldCondition(key="note_id", match=rest.MatchValue(value=note_id))])
+        pts, _ = self.client.scroll(self.notes_col, with_payload=True, with_vectors=False, limit=1, scroll_filter=f)
+        return (pts[0].payload or None) if pts else None
+
+    def get_chunks(self, note_id: str) -> List[Dict[str, Any]]:
+        f = rest.Filter(must=[rest.FieldCondition(key="note_id", match=rest.MatchValue(value=note_id))])
+        pts = self._scroll(self.chunks_col, f)
+        # Sortierung analog Export
+        def key(pl):
+            p = pl.payload or {}
+            s = p.get("seq") or 0
+            ci = p.get("chunk_index") or 0
+            n = 0
+            cid = p.get("chunk_id") or ""
+            if isinstance(cid, str) and "#" in cid:
+                try:
+                    n = int(cid.rsplit("#", 1)[-1])
+                except Exception:
+                    n = 0
+            return (int(s), int(ci), n)
+        pts_sorted = sorted(pts, key=key)
+        return [p.payload or {} for p in pts_sorted]
+
+    def neighbors(self, source_id: str, kinds: Optional[Iterable[str]] = None,
+                  scope: Optional[Iterable[str]] = None, depth: int = 1) -> Dict[str, List[Dict[str, Any]]]:
+        """
+        Liefert eingehende & ausgehende Nachbarn (nur nach kind gefiltert).
+        depth==1: direkte Kanten.
+        """
+        kinds = list(kinds) if kinds else None
+        must = [rest.FieldCondition(key="source_id", match=rest.MatchValue(value=source_id))]
+        if kinds:
+            must.append(rest.FieldCondition(key="kind", match=rest.MatchAny(any=kinds)))
+        f = rest.Filter(must=must)
+        edges = self._scroll(self.edges_col, f)
+        out = {"out": [], "in": []}
+        for e in edges:
+            out["out"].append(e.payload or {})
+        # Inverse Richtung (eingehend)
+        must_in = [rest.FieldCondition(key="target_id", match=rest.MatchValue(value=source_id))]
+        if kinds:
+            must_in.append(rest.FieldCondition(key="kind", match=rest.MatchAny(any=kinds)))
+        f_in = rest.Filter(must=must_in)
+        edges_in = self._scroll(self.edges_col, f_in)
+        for e in edges_in:
+            out["in"].append(e.payload or {})
+        return out
+
+    def walk_bfs(self, source_id: str, kinds: Iterable[str], max_depth: int = 2) -> Set[str]:
+        visited: Set[str] = {source_id}
+        frontier: Set[str] = {source_id}
+        kinds = list(kinds)
+        for _ in range(max_depth):
+            nxt: Set[str] = set()
+            for s in frontier:
+                neigh = self.neighbors(s, kinds=kinds)
+                for e in neigh["out"]:
+                    t = e.get("target_id")
+                    if isinstance(t, str) and t not in visited:
+                        visited.add(t)
+                        nxt.add(t)
+            frontier = nxt
+            if not frontier:
+                break
+        return visited
+
+    def context_for_note(self, note_id: str, kinds: Iterable[str] = ("references","backlink"), max_neighbors: int = 12) -> Dict[str, Any]:
+        """
+        Heuristischer Kontext: eigene Chunks + Nachbarn nach Kantenarten, dedupliziert.
+        """
+        note = self.get_note(note_id) or {}
+        chunks = self.get_chunks(note_id)
+        neigh = self.neighbors(note_id, kinds=list(kinds))
+        targets = []
+        for e in neigh["out"]:
+            t = e.get("target_id")
+            if isinstance(t, str):
+                targets.append(t)
+        for e in neigh["in"]:
+            s = e.get("source_id")
+            if isinstance(s, str):
+                targets.append(s)
+        # de-dupe
+        seen = set()
+        uniq = []
+        for t in targets:
+            if t not in seen:
+                seen.add(t)
+                uniq.append(t)
+        uniq = uniq[:max_neighbors]
+        neighbor_notes = [self.get_note(t) for t in uniq]
+        return {
+            "note": note,
+            "chunks": chunks,
+            "neighbors": [n for n in neighbor_notes if n],
+            "edges_out": neigh["out"],
+            "edges_in": neigh["in"],
+        }
+
+# Optional: Mini-CLI
+if __name__ == "__main__":  # pragma: no cover
+    import argparse, json
+    ap = argparse.ArgumentParser()
+    ap.add_argument("--prefix", help="Collection-Prefix (überschreibt ENV)")
+    ap.add_argument("--note-id", required=True)
+    ap.add_argument("--neighbors", action="store_true", help="Nur Nachbarn anzeigen")
+    args = ap.parse_args()
+    svc = GraphService(prefix=args.prefix)
+    if args.neighbors:
+        out = svc.neighbors(args.note_id, kinds=["references","backlink","prev","next","belongs_to"])
+    else:
+        out = svc.context_for_note(args.note_id)
+    print(json.dumps(out, ensure_ascii=False, indent=2))