Project discover neighbors from scanned seeds only.

Accept optional seed ids on project-neighbors; canvas discover passes scanned fabric nodes and places new peers near them.

Co-authored-by: Cursor <cursoragent@cursor.com>

netx_api/topology_router.py

@@ -43,6 +43,7 @@ from .topology_schemas import (
     ViewNodesRemove,
     ViewPopulateRequest,
     ViewPositionsPatch,
+    ViewProjectNeighborsRequest,
 )
 from .topology_discover import get_discover_job, start_discover_job
 from .topology_fabric import (
@@ -319,8 +320,14 @@ def api_create_topology_placeholder(
 
 
 @router.post("/views/{view_id}/project-neighbors")
-def api_project_neighbors(view_id: str, db: Session = Depends(get_db)) -> dict[str, Any]:
-    return project_fabric_neighbors_to_view(db, view_id).model_dump()
+def api_project_neighbors(
+    view_id: str,
+    body: ViewProjectNeighborsRequest | None = None,
+    db: Session = Depends(get_db),
+) -> dict[str, Any]:
+    return project_fabric_neighbors_to_view(
+        db, view_id, body or ViewProjectNeighborsRequest()
+    ).model_dump()
 
 
 @router.post("/views/{view_id}/populate")

netx_api/topology_schemas.py

@@ -238,6 +238,18 @@ class ViewPopulateRequest(BaseModel):
     freeze_after: bool = True
 
 
+class ViewProjectNeighborsRequest(BaseModel):
+    """Project fabric neighbors onto a view.
+
+    When seed ids are omitted, expand from every node already on the canvas.
+    When provided, expand only from those seeds (resolved to fabric nodes that
+    are already placed on the view).
+    """
+
+    seed_fabric_node_ids: list[str] = Field(default_factory=list)
+    managed_ne_ids: list[str] = Field(default_factory=list)
+
+
 class ViewNodeIn(BaseModel):
     fabric_node_id: str = Field(min_length=1, max_length=64)
     x: float = 0.0

netx_api/topology_views_graph.py

@@ -70,6 +70,7 @@ from .topology_schemas import (
     ViewPopulateOut,
     ViewPopulateRequest,
     ViewPositionsPatch,
+    ViewProjectNeighborsRequest,
 )
 
 # ---------------------------------------------------------------------------
@@ -288,18 +289,31 @@ def _place_fabric_ids_on_view(
     fabric_ids: list[str],
     *,
     existing: set[str],
+    near_fabric_ids: set[str] | None = None,
 ) -> int:
     now = _utcnow()
     added = 0
     vnodes = db.query(TopoViewNode).filter(TopoViewNode.view_id == view.id).all()
-    max_x = max((float(vn.x or 0) for vn in vnodes), default=40.0)
-    base_x = max_x + 200.0
+    anchor = None
+    near = {str(x).strip() for x in (near_fabric_ids or set()) if str(x).strip()}
+    if near:
+        for vn in vnodes:
+            if vn.fabric_node_id in near:
+                anchor = vn
+                break
+    if anchor is not None:
+        base_x = float(anchor.x or 0.0) + 200.0
+        base_y = float(anchor.y or 0.0)
+    else:
+        max_x = max((float(vn.x or 0) for vn in vnodes), default=40.0)
+        base_x = max_x + 200.0
+        base_y = 40.0
     cols = max(1, int(len(fabric_ids) ** 0.5) or 1)
     for i, fid in enumerate(fabric_ids):
         if fid in existing or db.get(TopoFabricNode, fid) is None:
             continue
         x = base_x + (i % cols) * 180.0
-        y = 40.0 + (i // cols) * 120.0
+        y = base_y + (i // cols) * 120.0
         db.add(
             TopoViewNode(
                 id=uuid4().hex,
@@ -897,8 +911,16 @@ def _neighbor_ids(
     return found
 
 
-def project_fabric_neighbors_to_view(db: Session, view_id: str) -> TopologyViewGraphOut:
-    """Add in-scope fabric neighbors onto the leaf view (bounded by membership)."""
+def project_fabric_neighbors_to_view(
+    db: Session,
+    view_id: str,
+    body: ViewProjectNeighborsRequest | None = None,
+) -> TopologyViewGraphOut:
+    """Add in-scope fabric neighbors onto the leaf view (bounded by membership).
+
+    Optional seeds limit expansion to neighbors of those fabric nodes (must
+    already be on the view). Empty seeds → expand from every canvas node.
+    """
     merge_duplicate_fabric_nodes(db)
     view = _get_view_or_404(db, view_id)
     mem = _membership_for_view(view)
@@ -909,6 +931,7 @@ def project_fabric_neighbors_to_view(db: Session, view_id: str) -> TopologyViewG
     hops = int(mem.get("expand_hops") or 1)
     filt = dict(view.filter or {})
     layer = str(filt.get("layer") or "physical").strip() or "physical"
+    req = body or ViewProjectNeighborsRequest()
 
     vnodes = db.query(TopoViewNode).filter(TopoViewNode.view_id == view.id).all()
     # Drop placements pointing at missing fabric rows only (keep LLDP placeholders).
@@ -929,7 +952,25 @@ def project_fabric_neighbors_to_view(db: Session, view_id: str) -> TopologyViewG
         g.truncate_reason = g.truncate_reason or "membership_cap"
         return g
 
-    peer_ids = _neighbor_ids(db, seed_ids=existing, layer=layer, hops=hops)
+    seed_ids: set[str] = {
+        str(x).strip() for x in (req.seed_fabric_node_ids or []) if str(x).strip()
+    }
+    for mid in req.managed_ne_ids or []:
+        mid_s = str(mid or "").strip()
+        if not mid_s:
+            continue
+        for fid in existing:
+            fn = db.get(TopoFabricNode, fid)
+            if fn is not None and str(fn.managed_ne_id or "").strip() == mid_s:
+                seed_ids.add(fid)
+    if seed_ids:
+        seed_ids &= existing
+        if not seed_ids:
+            return get_view_graph(db, view.id)
+    else:
+        seed_ids = set(existing)
+
+    peer_ids = _neighbor_ids(db, seed_ids=seed_ids, layer=layer, hops=hops)
     to_add: list[str] = []
     for peer in sorted(peer_ids):
         if peer in existing:
@@ -947,7 +988,9 @@ def project_fabric_neighbors_to_view(db: Session, view_id: str) -> TopologyViewG
 
     truncated = len(peer_ids) > len(to_add)
     if to_add:
-        _place_fabric_ids_on_view(db, view, to_add, existing=existing)
+        _place_fabric_ids_on_view(
+            db, view, to_add, existing=existing, near_fabric_ids=seed_ids
+        )
         db.commit()
     g = get_view_graph(db, view.id)
     if truncated:

packages/netx-topology-mcp/src/netx_topology_mcp/http_tools.py

@@ -256,7 +256,14 @@ def _project_topology_neighbors(args: dict[str, Any]) -> dict[str, Any]:
     view_id = str(args.get("view_id") or "").strip()
     if not view_id:
         return {"ok": False, "error": "view_id_required"}
-    return _data(http_json("POST", f"/v1/topology/views/{view_id}/project-neighbors", body={}))
+    body: dict[str, Any] = {}
+    seeds = args.get("seed_fabric_node_ids") or args.get("fabric_node_ids") or []
+    if isinstance(seeds, list) and seeds:
+        body["seed_fabric_node_ids"] = [str(x).strip() for x in seeds if str(x).strip()]
+    mids = args.get("managed_ne_ids") or []
+    if isinstance(mids, list) and mids:
+        body["managed_ne_ids"] = [str(x).strip() for x in mids if str(x).strip()]
+    return _data(http_json("POST", f"/v1/topology/views/{view_id}/project-neighbors", body=body))
 
 
 def _get_topology_fabric_summary(_args: dict[str, Any]) -> dict[str, Any]:
@@ -515,11 +522,25 @@ HTTP_MCP_TOOLS: list[dict[str, Any]] = [
         "name": "projectTopologyNeighbors",
         "description": (
             "Project existing LLDP fabric neighbors of nodes already on the view onto the canvas. "
-            "Only places nodes that already exist in fabric."
+            "Only places nodes that already exist in fabric. "
+            "Optional seed_fabric_node_ids / managed_ne_ids limit expansion to those seeds; "
+            "omit to expand from every node on the view."
         ),
         "inputSchema": {
             "type": "object",
-            "properties": {"view_id": {"type": "string"}},
+            "properties": {
+                "view_id": {"type": "string"},
+                "seed_fabric_node_ids": {
+                    "type": "array",
+                    "items": {"type": "string"},
+                    "description": "Optional fabric node ids already on the view to expand from",
+                },
+                "managed_ne_ids": {
+                    "type": "array",
+                    "items": {"type": "string"},
+                    "description": "Optional managed NE ids to resolve to on-view fabric seeds",
+                },
+            },
             "required": ["view_id"],
             "additionalProperties": False,
         },

tests/test_topology.py

@@ -33,6 +33,7 @@ from netx_api.topology_schemas import (
     ViewNodesAdd,
     ViewPopulateRequest,
     ViewPositionsPatch,
+    ViewProjectNeighborsRequest,
     ViewNodeIn,
 )
 
@@ -679,6 +680,31 @@ class FabricTopologyTests(unittest.TestCase):
         self.assertLessEqual(len(g.nodes), 2)
         self.assertTrue(g.truncated or len(g.nodes) == 2)
 
+        # Seed-scoped project: expand only from node 0 → only node 1 among line peers.
+        view2 = svc.create_view(
+            self.db,
+            TopologyViewCreate(
+                name=f"CapSeed-{suffix}",
+                folder_id=self._region(f"CapSeedR-{suffix}"),
+                role="core",
+                filter={"membership": {"expand_hops": 1, "max_nodes": 50, "frozen": False}},
+            ),
+        )
+        # Place endpoints 0 and 2 (not adjacent); seed from 0 should add 1, not 3.
+        svc.add_nodes_to_view(
+            self.db, view2.id, ViewNodesAdd(managed_ne_ids=[nes[0].id, nes[2].id])
+        )
+        g2 = svc.project_fabric_neighbors_to_view(
+            self.db,
+            view2.id,
+            ViewProjectNeighborsRequest(seed_fabric_node_ids=[nodes[0].id]),
+        )
+        ids2 = {n.fabric_node_id for n in g2.nodes}
+        self.assertIn(nodes[0].id, ids2)
+        self.assertIn(nodes[1].id, ids2)
+        self.assertIn(nodes[2].id, ids2)
+        self.assertNotIn(nodes[3].id, ids2)
+
         pop = svc.populate_view(
             self.db,
             view.id,

web/src/i18n/en.ts

@@ -1486,7 +1486,7 @@ const en = {
     snapGrid: "Snap to grid",
     autoLayoutDiscover: "Auto-layout after discover",
     discoverAutoAddUnmatched: "Auto-add unmatched NEs as placeholders on discover",
-    discoverProjectNeighbors: "Project direct neighbors onto canvas after discover",
+    discoverProjectNeighbors: "After discover, project neighbors of scanned NEs onto the canvas",
     undo: "Undo",
     redo: "Redo",
     discoverSelected: "Discover selected ({{count}})",

web/src/i18n/zh.ts

@@ -1477,7 +1477,7 @@ const zh = {
     snapGrid: "网格吸附",
     autoLayoutDiscover: "发现后自动布局",
     discoverAutoAddUnmatched: "发现时自动入库未匹配网元（占位）",
-    discoverProjectNeighbors: "发现后将直连邻居加入画布",
+    discoverProjectNeighbors: "发现后将本次扫描网元的直连邻居加入画布",
     undo: "撤销",
     redo: "重做",
     discoverSelected: "发现选中 ({{count}})",

web/src/pages/TopologyPage.tsx

@@ -1620,13 +1620,16 @@ export function TopologyPage() {
           throw new Error(job.error || "discover_failed");
         }
         const projected = discoverProjectNeighbors
-          ? await projectTopologyNeighbors(mapId)
+          ? await projectTopologyNeighbors(mapId, {
+              seed_fabric_node_ids: scoped.map((n) => n.id),
+            })
           : await fetchTopologyGraph(mapId);
         queryClient.setQueryData(queryKeys.topologyGraph(mapId), projected);
         appliedMapIdRef.current = mapId;
         let { rfNodes, rfEdges } = graphToFlow(projected.nodes, projected.edges, edgeDefaults);
         // Keep existing node positions when we did not auto-layout.
         const localPos = new Map(nodes.map((n) => [n.id, n.position]));
+        const beforeIds = new Set(nodes.map((n) => n.id));
         rfNodes = rfNodes.map((n) => {
           const p = localPos.get(n.id);
           return p ? { ...n, position: { ...p } } : n;
@@ -1649,7 +1652,8 @@ export function TopologyPage() {
         setNodes(rfNodes);
         setEdges(rfEdges);
         historyLockRef.current = false;
-        if (didAutoLayout) {
+        const addedNodes = rfNodes.filter((n) => !beforeIds.has(n.id)).length;
+        if (didAutoLayout || addedNodes > 0) {
           needsInitialFitRef.current = true;
           scheduleFitView(FIT_VIEW_OPTS);
         }

web/src/services/api.ts

@@ -1084,8 +1084,14 @@ export const removeTopologyViewNodes = (viewId: string, fabricNodeIds: string[])
     fabric_node_ids: fabricNodeIds,
   });
 
-export const projectTopologyNeighbors = (viewId: string) =>
-  apiPost<TopologyViewGraph>(`/v1/topology/views/${encodeURIComponent(viewId)}/project-neighbors`, {});
+export const projectTopologyNeighbors = (
+  viewId: string,
+  body?: { seed_fabric_node_ids?: string[]; managed_ne_ids?: string[] },
+) =>
+  apiPost<TopologyViewGraph>(
+    `/v1/topology/views/${encodeURIComponent(viewId)}/project-neighbors`,
+    body || {},
+  );
 
 export const patchTopologyEdgeStyle = (
   viewId: string,