diff --git a/AGENTS.md b/AGENTS.md
index 37f9f28a51..06eb1683e6 100644
--- a/AGENTS.md
+++ b/AGENTS.md
@@ -76,8 +76,9 @@ Rules:
 - `unit` (no tag) must stay free of external-service dependencies so `go test ./...` passes without MySQL/MinIO/ES/Infinity/LLM. The native CGO static libraries (`office_oxide`/`pdfium`/`pdf_oxide`) are still required at build time and are wired automatically by `build.sh --test`; that is expected, not an external service.
 
 ## Working Rules
-- Before editing, inspect the nearest code path that actually owns the behavior.
+- When reviewing documentation or code, inspect the full affected path and report all verifiable findings in one review; do not return after only a few findings and expose further issues in later rounds.
 - When handling review comments, independently verify each substantive claim against the current code or tests before accepting, rejecting, or acting on it.
+- Before editing, inspect the nearest code path that actually owns the behavior.
 - Keep changes small and local unless the task is explicitly a broader refactor.
 - Prefer one implementation path instead of preserving old and new versions side by side.
 - Preserve behavior with focused tests when the behavior is still valid; do not keep tests that protect obsolete behavior.
diff --git a/internal/entity/dataset.go b/internal/entity/dataset.go
index 25392cdf9b..1c1bad0ddf 100644
--- a/internal/entity/dataset.go
+++ b/internal/entity/dataset.go
@@ -124,7 +124,19 @@ type Knowledgebase struct {
 	WikiTaskFinishAt       *time.Time `gorm:"column:wiki_task_finish_at" json:"wiki_task_finish_at,omitempty"`
 	SkillTaskID            *string    `gorm:"column:skill_task_id;size:32;index" json:"skill_task_id,omitempty"`
 	SkillTaskFinishAt      *time.Time `gorm:"column:skill_task_finish_at" json:"skill_task_finish_at,omitempty"`
-	Status                 *string    `gorm:"column:status;size:1;index;default:'1'" json:"status,omitempty"`
+	// Dataset-level structure merge task state (plan §8, mirror Python
+	// _INDEX_TYPE_TO_TASK_ID_FIELD's per-structure-index entries).
+	StructureGraphTaskID         *string    `gorm:"column:structure_graph_task_id;size:32;index" json:"structure_graph_task_id,omitempty"`
+	StructureGraphTaskFinishAt   *time.Time `gorm:"column:structure_graph_task_finish_at" json:"structure_graph_task_finish_at,omitempty"`
+	StructureMindmapTaskID       *string    `gorm:"column:structure_mindmap_task_id;size:32;index" json:"structure_mindmap_task_id,omitempty"`
+	StructureMindmapTaskFinishAt *time.Time `gorm:"column:structure_mindmap_task_finish_at" json:"structure_mindmap_task_finish_at,omitempty"`
+	TimelineTaskID               *string    `gorm:"column:timeline_task_id;size:32;index" json:"timeline_task_id,omitempty"`
+	TimelineTaskFinishAt         *time.Time `gorm:"column:timeline_task_finish_at" json:"timeline_task_finish_at,omitempty"`
+	SessionGraphTaskID           *string    `gorm:"column:session_graph_task_id;size:32;index" json:"session_graph_task_id,omitempty"`
+	SessionGraphTaskFinishAt     *time.Time `gorm:"column:session_graph_task_finish_at" json:"session_graph_task_finish_at,omitempty"`
+	SessionEssenceTaskID         *string    `gorm:"column:session_essence_task_id;size:32;index" json:"session_essence_task_id,omitempty"`
+	SessionEssenceTaskFinishAt   *time.Time `gorm:"column:session_essence_task_finish_at" json:"session_essence_task_finish_at,omitempty"`
+	Status                       *string    `gorm:"column:status;size:1;index;default:'1'" json:"status,omitempty"`
 	BaseModel
 }
 
diff --git a/internal/handler/dataset_artifact.go b/internal/handler/dataset_artifact.go
index 3ac47a86f2..2d091b192f 100644
--- a/internal/handler/dataset_artifact.go
+++ b/internal/handler/dataset_artifact.go
@@ -14,6 +14,7 @@
 package handler
 
 import (
+	"errors"
 	"net/http"
 	"strconv"
 
@@ -276,35 +277,56 @@ func (h *DatasetArtifactHandler) GetArtifactGraph(c *gin.Context) {
 	common.SuccessWithData(c, graph, "success")
 }
 
-// ListStructures handles GET /artifacts/structure — list compiled structures of a dataset.
+// ListStructures handles GET /artifacts/structure?kind=<kind> — the dataset-scope
+// structure graph for a resolved kind (mirrors Python get_dataset_structure).
+// kind is REQUIRED: missing or invalid → 400 ARGUMENT_ERROR.
 func (h *DatasetArtifactHandler) ListStructures(c *gin.Context) {
 	_, tenantID, _ := h.datasetOwner(c, c.Param("dataset_id"))
 	if tenantID == "" {
 		return
 	}
 	datasetID := c.Param("dataset_id")
-	structureKind := c.Query("structure_kind")
-	structureIndexType := c.Query("structure_index_type")
-	items, total, err := h.svc.ListStructures(c.Request.Context(), tenantID, datasetID, structureKind, structureIndexType)
-	if err != nil {
-		common.ErrorWithCode(c, common.CodeDataError, err.Error())
+	kind := c.Query("kind")
+	if kind == "" {
+		common.ErrorWithCode(c, common.CodeArgumentError, "kind is required")
 		return
 	}
-	common.SuccessWithData(c, gin.H{"total": total, "structures": items}, "success")
+	in := service.DatasetStructureGraphInput{TenantID: tenantID, DatasetID: datasetID, Kind: kind}
+	resp, err := h.svc.GetDatasetStructure(c.Request.Context(), in)
+	if err != nil {
+		if errors.Is(err, service.ErrInvalidStructureKind) {
+			common.ErrorWithCode(c, common.CodeArgumentError, err.Error())
+		} else {
+			common.ErrorWithCode(c, common.CodeServerError, err.Error())
+		}
+		return
+	}
+	common.SuccessWithData(c, resp, "success")
 }
 
-// DeleteStructures handles DELETE /artifacts/structure — delete compiled structures of a dataset.
+// DeleteStructures handles DELETE /artifacts/structure?kind=<kind>&wipe=<bool> —
+// cancel the kind's task (wipe=false) or delete its dataset rows (wipe=true).
+// kind is REQUIRED.
 func (h *DatasetArtifactHandler) DeleteStructures(c *gin.Context) {
 	_, tenantID, _ := h.datasetOwner(c, c.Param("dataset_id"))
 	if tenantID == "" {
 		return
 	}
 	datasetID := c.Param("dataset_id")
-	structureKind := c.Query("structure_kind")
-	structureIndexType := c.Query("structure_index_type")
-	n, err := h.svc.DeleteStructures(c.Request.Context(), tenantID, datasetID, structureKind, structureIndexType)
+	kind := c.Query("kind")
+	if kind == "" {
+		common.ErrorWithCode(c, common.CodeArgumentError, "kind is required")
+		return
+	}
+	wipe := c.Query("wipe") == "true"
+	in := service.DatasetStructureGraphInput{TenantID: tenantID, DatasetID: datasetID, Kind: kind, Wipe: wipe}
+	n, err := h.svc.DeleteDatasetStructure(c.Request.Context(), in)
 	if err != nil {
-		common.ErrorWithCode(c, common.CodeDataError, err.Error())
+		if errors.Is(err, service.ErrInvalidStructureKind) {
+			common.ErrorWithCode(c, common.CodeArgumentError, err.Error())
+		} else {
+			common.ErrorWithCode(c, common.CodeServerError, err.Error())
+		}
 		return
 	}
 	common.SuccessWithData(c, gin.H{"deleted": n}, "success")
diff --git a/internal/ingestion/component/knowledge_compiler/component.go b/internal/ingestion/component/knowledge_compiler/component.go
index 8b29cbebb1..29696603cd 100644
--- a/internal/ingestion/component/knowledge_compiler/component.go
+++ b/internal/ingestion/component/knowledge_compiler/component.go
@@ -157,11 +157,31 @@ func (c *KnowledgeCompilerComponent) Invoke(ctx context.Context, db *gorm.DB, in
 		deps.TenantID = tenantID
 		deps.DatasetID = datasetID
 
+		// Per-spec Inputs copy: each spec must get its own VariantSpecific map,
+		// otherwise specIn.VariantSpecific below would mutate the shared map and
+		// let a later template inherit the previous template's parser_config
+		// (a template with an empty config would then run with the wrong parser
+		// behavior). Copy the map (and preserve an empty map when nil).
 		specIn := in
-		if specIn.VariantSpecific == nil {
-			specIn.VariantSpecific = map[string]any{}
+		specIn.VariantSpecific = make(map[string]any, len(in.VariantSpecific)+1)
+		for k, v := range in.VariantSpecific {
+			specIn.VariantSpecific[k] = v
+		}
+		// The template config (flat: kind/entity/relation/plan/…) is delivered to
+		// the structure and wiki variants under the "parser_config" key — the SAME
+		// key those variants read (structure.Run / wikiPipeline.mapBatch do
+		// VariantSpecific["parser_config"]). Storing it as "config" left the
+		// variants with a nil config, so InferType saw no "kind" and fell back to
+		// "list" (breaking timeline: its compile_kwd became "list" instead of
+		// "timeline", so dropIsolatedTimelineEntities never ran and the timeline
+		// rendered every entity isolated).
+		//
+		// Only overwrite when the template actually carries a config: an empty
+		// template config (e.g. a resolver stub) must not clobber a parser_config
+		// the caller already supplied on the inputs.
+		if len(spec.Config) > 0 {
+			specIn.VariantSpecific["parser_config"] = spec.Config
 		}
-		specIn.VariantSpecific["config"] = spec.Config
 
 		var o common.Outputs
 		switch variant {
@@ -564,23 +584,14 @@ func applyVariantColumns(doc *schema.ChunkDoc, p common.Product) error {
 		}
 
 	case common.VariantMindmap:
-		// Tree nodes: depth_int records the outline level.
-		if v, ok := metaInt(p.Meta, "level"); ok {
-			if err := doc.SetExtraValue("depth_int", v); err != nil {
-				return err
-			}
-		}
-		if v := metaString(p.Meta, "name"); v != "" {
-			if err := doc.SetExtraValue("title_kwd", v); err != nil {
-				return err
-			}
-			setTitleTokens(doc, v)
-		}
-		if v := metaStringSlice(p.Meta, "children"); len(v) > 0 {
-			if err := doc.SetExtraValue("children_kwd", v); err != nil {
-				return err
-			}
-		}
+		// Mindmap now emits entity/relation rows (plan §1.2) so it participates in
+		// dataset-level merge exactly like graph/timeline: each node is an entity,
+		// each parent→child edge is a relation. Reuse the shared structure-graph
+		// column contract (knowledge_graph_kwd + from/to_entity_kwd + name_kwd +
+		// entity_type_kwd + mention_count_int). The relation type lives in the
+		// content_with_weight payload ({"from","to","type"}), matching Python —
+		// NOT a dedicated relation_type_kwd column.
+		return applyStructureGraphColumns(doc, p, kind)
 	}
 
 	return nil
diff --git a/internal/ingestion/component/knowledge_compiler/component_test.go b/internal/ingestion/component/knowledge_compiler/component_test.go
index dc055d1bcd..21420a5805 100644
--- a/internal/ingestion/component/knowledge_compiler/component_test.go
+++ b/internal/ingestion/component/knowledge_compiler/component_test.go
@@ -388,21 +388,27 @@ func TestKnowledgeCompiler_Tree_EndToEnd(t *testing.T) {
 
 func TestKnowledgeCompiler_Mindmap_EndToEnd(t *testing.T) {
 	installProseDeps(t)
-	// The proseChat reply is flat text; parseOutline still yields a root + the
-	// reply as a child node, so chunks are non-empty and parent-linked.
+	// The proseChat reply is flat text; ShapeTree yields a bare root (no parsed
+	// children). Mindmap now emits entity/relation rows (plan §1.2): every node
+	// is an entity, every parent→child edge a relation. With a flat reply there
+	// is at least one entity (the root) and it must carry name_kwd +
+	// knowledge_graph_kwd="entity" (the structure-graph storage contract).
 	chunks := runVariant(t, "mindmap", nil)
-	// Root chunk must have empty parent_kwd and kind "root".
-	var root map[string]any
+	entityCount := 0
 	for _, c := range chunks {
-		if kind, _ := c["kc_kind"].(string); kind == "root" {
-			root = c
+		kind, _ := c["kc_kind"].(string)
+		if kind == "entity" {
+			entityCount++
+			if _, ok := c["name_kwd"]; !ok {
+				t.Fatalf("mindmap entity chunk missing name_kwd: %+v", c)
+			}
+			if kg, _ := c["knowledge_graph_kwd"].(string); kg != "entity" {
+				t.Fatalf("mindmap entity chunk knowledge_graph_kwd = %q, want entity", kg)
+			}
 		}
 	}
-	if root == nil {
-		t.Fatalf("mindmap: no root chunk")
-	}
-	if pid, _ := root["parent_kwd"].(string); pid != "" {
-		t.Fatalf("mindmap: root parent_kwd = %q, want empty", pid)
+	if entityCount == 0 {
+		t.Fatalf("mindmap: no entity chunks; got %d chunks", len(chunks))
 	}
 }
 
diff --git a/internal/ingestion/component/knowledge_compiler/mindmap/mindmap.go b/internal/ingestion/component/knowledge_compiler/mindmap/mindmap.go
index b643f03f53..61460d84b3 100644
--- a/internal/ingestion/component/knowledge_compiler/mindmap/mindmap.go
+++ b/internal/ingestion/component/knowledge_compiler/mindmap/mindmap.go
@@ -12,7 +12,6 @@ package mindmap
 
 import (
 	"context"
-	"encoding/json"
 	"fmt"
 	"strings"
 
@@ -132,38 +131,47 @@ func Run(ctx context.Context, deps common.Deps, param common.Param, inputs commo
 	return out, nil
 }
 
-// treeToProducts flattens the shaped mind-map tree into Products. The root
-// becomes a "root" product whose content is the serialized {"id","children"}
-// tree (Python's MindMapResult.output shape); each inner node becomes a
-// "node" product linked via parent_id.
+// treeToProducts flattens the shaped mind-map tree into entity/relation Products
+// so mindmap participates in dataset-level merge exactly like graph (plan §1.2,
+// aligning with Python's dataset_structure_merger which merges
+// knowledge_graph_kwd IN {entity,relation} rows for structure_mindmap too).
 //
-// NOTE: the per-node "node" products (content = the node title, plus a
-// meta["children"] list of immediate child titles) are a Go component-layer
-// contract for streaming the tree into the upstream chunk list. They go
-// beyond Python's nested dict output and exist so downstream code can index
-// each node independently with parent links.
+// Mapping:
+//   - each node (including the root) → an entity product (kind="entity",
+//     name = node id, type = "mindmap").
+//   - each parent→child edge → a relation product (kind="relation",
+//     from = parent id, to = child id, type = "related" — Python's default).
+//
+// The entity/relation discriminator is carried in Meta["kind"] so the consumer's
+// mergeStructureDataset buckets entities by (name,type) and relations by
+// (from,type,to), matching graph/timeline.
 func treeToProducts(tenantID, docID string, root *utility.Node) []common.Product {
 	var out []common.Product
-	rootID := common.StableRowID(tenantID, docID, string(common.VariantMindmap), "root")
+	if root == nil || root.ID == "" {
+		return out
+	}
+	seen := map[string]bool{}
+	// Entity: root node.
 	out = append(out, common.Product{
-		ID:       rootID,
+		ID:       common.StableRowID(tenantID, docID, string(common.VariantMindmap), "entity", root.ID),
 		DocID:    docID,
 		TenantID: tenantID,
 		Variant:  common.VariantMindmap,
-		Content:  serializeNode(root),
+		Content:  root.ID,
 		Meta: map[string]any{
-			"kind":  "root",
-			"level": 0,
-			"name":  root.ID,
+			"kind":        "entity",
+			"name":        root.ID,
+			"entity_type": "mindmap",
+			"compile_kwd": "mindmap",
 		},
 	})
+	seen[root.ID] = true
 
 	type pending struct {
-		node     *utility.Node
-		parentID string
-		level    int
+		node   *utility.Node
+		parent string
 	}
-	queue := []pending{{root, rootID, 0}}
+	queue := []pending{{root, root.ID}}
 	for len(queue) > 0 {
 		p := queue[0]
 		queue = queue[1:]
@@ -171,64 +179,45 @@ func treeToProducts(tenantID, docID string, root *utility.Node) []common.Product
 			if child.ID == "" {
 				continue
 			}
-			level := p.level + 1
-			id := common.StableRowID(tenantID, docID, string(common.VariantMindmap), "node", child.ID)
-			childTitles := make([]string, 0, len(child.Children))
-			for _, gc := range child.Children {
-				if gc.ID != "" {
-					childTitles = append(childTitles, gc.ID)
-				}
-			}
-			meta := map[string]any{
-				"kind":  "node",
-				"level": level,
-				"name":  child.ID,
-			}
-			if len(childTitles) > 0 {
-				meta["children"] = childTitles
+			// Entity: child node (dedup by id so a DAG-shaped tree does not emit
+			// the same node twice).
+			if !seen[child.ID] {
+				seen[child.ID] = true
+				out = append(out, common.Product{
+					ID:       common.StableRowID(tenantID, docID, string(common.VariantMindmap), "entity", child.ID),
+					DocID:    docID,
+					TenantID: tenantID,
+					Variant:  common.VariantMindmap,
+					Content:  child.ID,
+					Meta: map[string]any{
+						"kind":        "entity",
+						"name":        child.ID,
+						"entity_type": "mindmap",
+						"compile_kwd": "mindmap",
+					},
+				})
 			}
+			// Relation: parent → child edge (type = "related", Python default).
 			out = append(out, common.Product{
-				ID:       id,
+				ID:       common.StableRowID(tenantID, docID, string(common.VariantMindmap), "relation", p.parent, child.ID),
 				DocID:    docID,
 				TenantID: tenantID,
 				Variant:  common.VariantMindmap,
-				Content:  child.ID,
-				ParentID: p.parentID,
-				Meta:     meta,
+				Content:  p.parent + " related " + child.ID,
+				Meta: map[string]any{
+					"kind":          "relation",
+					"from":          p.parent,
+					"to":            child.ID,
+					"relation_type": "related",
+					"compile_kwd":   "mindmap",
+				},
 			})
-			queue = append(queue, pending{child, id, level})
+			queue = append(queue, pending{child, child.ID})
 		}
 	}
 	return out
 }
 
-// jsonNode mirrors the {"id","children"} mind-map node shape (Python's
-// MindMapResult.output) for JSON serialization.
-type jsonNode struct {
-	ID       string      `json:"id"`
-	Children []*jsonNode `json:"children"`
-}
-
-func toJSONNode(n *utility.Node) *jsonNode {
-	jn := &jsonNode{ID: n.ID}
-	for _, c := range n.Children {
-		jn.Children = append(jn.Children, toJSONNode(c))
-	}
-	return jn
-}
-
-// serializeNode renders the tree in Python's MindMapResult.output shape:
-// {"id": ..., "children": [...]}. Uses encoding/json so every control
-// character (including \r, \b, \f, etc.) is escaped correctly; the previous
-// hand-rolled serializer only escaped ", \, \n and \t.
-func serializeNode(node *utility.Node) string {
-	b, err := json.Marshal(toJSONNode(node))
-	if err != nil {
-		return `{"id":"` + node.ID + `","children":[]}`
-	}
-	return string(b)
-}
-
 func chunkTexts(chunks []common.Chunk) []string {
 	var out []string
 	for _, c := range chunks {
diff --git a/internal/ingestion/component/knowledge_compiler/mindmap/mindmap_test.go b/internal/ingestion/component/knowledge_compiler/mindmap/mindmap_test.go
index 32e276ca99..a354ee2a25 100644
--- a/internal/ingestion/component/knowledge_compiler/mindmap/mindmap_test.go
+++ b/internal/ingestion/component/knowledge_compiler/mindmap/mindmap_test.go
@@ -1,7 +1,6 @@
 package mindmap
 
 import (
-	"encoding/json"
 	"strings"
 	"testing"
 
@@ -48,57 +47,50 @@ func TestTreeToProducts_ParentLinks(t *testing.T) {
 		{ID: "B"},
 	}}
 	products := treeToProducts("t1", "d1", root)
-	if len(products) != 5 {
-		t.Fatalf("products = %d, want 5 (root+A+A1+A2+B)", len(products))
+	// 5 entities (root, A, A1, A2, B) + 4 relations (root→A, A→A1, A→A2, root→B).
+	if len(products) != 9 {
+		t.Fatalf("products = %d, want 9 (5 entities + 4 relations)", len(products))
 	}
-	if products[0].Meta["kind"] != "root" || products[0].ParentID != "" {
-		t.Errorf("root product malformed: %+v", products[0].Meta)
-	}
-	if products[1].ParentID != products[0].ID {
-		t.Errorf("A parent link = %q, want root id", products[1].ParentID)
-	}
-	var aID string
+	entCount, relCount := 0, 0
+	fromTo := map[string]bool{}
 	for _, p := range products {
-		if p.Meta["name"] == "A" {
-			aID = p.ID
-		}
-	}
-	for _, p := range products {
-		if n, _ := p.Meta["name"].(string); n == "A1" || n == "A2" {
-			if p.ParentID != aID {
-				t.Errorf("%s parent = %q, want A id", n, p.ParentID)
+		kind, _ := p.Meta["kind"].(string)
+		switch kind {
+		case "entity":
+			entCount++
+			if p.Meta["entity_type"] != "mindmap" {
+				t.Errorf("entity %v type = %v, want mindmap", p.Meta["name"], p.Meta["entity_type"])
 			}
+			if p.Meta["compile_kwd"] != "mindmap" {
+				t.Errorf("entity %v compile_kwd = %v, want mindmap", p.Meta["name"], p.Meta["compile_kwd"])
+			}
+		case "relation":
+			relCount++
+			from, _ := p.Meta["from"].(string)
+			to, _ := p.Meta["to"].(string)
+			fromTo[from+"->"+to] = true
+			if p.Meta["relation_type"] != "related" {
+				t.Errorf("relation %v->%v type = %v, want related", from, to, p.Meta["relation_type"])
+			}
+		default:
+			t.Errorf("unexpected kind %q", kind)
+		}
+	}
+	if entCount != 5 || relCount != 4 {
+		t.Errorf("entities=%d relations=%d, want 5/4", entCount, relCount)
+	}
+	for _, edge := range []string{"root->A", "A->A1", "A->A2", "root->B"} {
+		if !fromTo[edge] {
+			t.Errorf("missing relation %s", edge)
 		}
 	}
 }
 
-func TestSerializeNode_Shape(t *testing.T) {
-	root := &utility.Node{ID: "Top \"quoted\"", Children: []*utility.Node{{ID: "child"}}}
-	js := serializeNode(root)
-	if !strings.HasPrefix(js, `{"id":"Top \"quoted\""`) {
-		t.Errorf("serializeNode = %q", js)
-	}
-}
-
-// TestSerializeNode_EscapesControlChars locks that serializeNode uses
-// encoding/json: control characters such as CR/LF/TAB/FF are escaped (not
-// embedded raw), so the output is always valid JSON.
-func TestSerializeNode_EscapesControlChars(t *testing.T) {
-	root := &utility.Node{ID: "a\rb\tc\fd", Children: []*utility.Node{{ID: "x\ny"}}}
-	js := serializeNode(root)
-	var dec struct {
-		ID       string `json:"id"`
-		Children []struct {
-			ID string `json:"id"`
-		} `json:"children"`
-	}
-	if err := json.Unmarshal([]byte(js), &dec); err != nil {
-		t.Fatalf("serializeNode produced invalid JSON: %v (%q)", err, js)
-	}
-	if dec.ID != "a\rb\tc\fd" {
-		t.Errorf("root id round-trip = %q, want %q", dec.ID, "a\rb\tc\fd")
-	}
-	if len(dec.Children) != 1 || dec.Children[0].ID != "x\ny" {
-		t.Errorf("child id round-trip = %+v", dec.Children)
+func TestTreeToProducts_EmptyAndNil(t *testing.T) {
+	if got := treeToProducts("t1", "d1", nil); len(got) != 0 {
+		t.Errorf("nil root produced %d products", len(got))
+	}
+	if got := treeToProducts("t1", "d1", &utility.Node{ID: ""}); len(got) != 0 {
+		t.Errorf("empty root id produced %d products", len(got))
 	}
 }
diff --git a/internal/ingestion/knowledge_compile/consumer.go b/internal/ingestion/knowledge_compile/consumer.go
index dd1c0b5cd8..f4acf69110 100644
--- a/internal/ingestion/knowledge_compile/consumer.go
+++ b/internal/ingestion/knowledge_compile/consumer.go
@@ -1026,17 +1026,40 @@ func pageIndexSummary(graphJSON string) string {
 // dataset_structure_merger._merge_bucket but is a self-contained from-scratch
 // path (B3: the legacy unified merge never aggregated structure by name/type).
 func (c *Consumer) mergeStructureDataset(ctx context.Context, tenant, kb string, products []kccommon.Product) error {
-	// Bucket by (lower(name), type) for entities and (lower(from), lower(to))
-	// for relations — relations have no "name" and must not be silently dropped
-	// (review issue 3).
-	type ekey struct{ name, typ string }
-	type rkey struct{ from, to string }
+	common.Info("knowledge_compile: mergeStructureDataset entry",
+		zap.String("kb_id", kb),
+		zap.Int("products", len(products)))
+	// Bucket by (lower(name), type, compile kind) for entities and
+	// (lower(from), lower(type), lower(to), compile kind) for relations —
+	// relations have no "name" and must not be silently dropped (review issue 3),
+	// and the relation type + compile kind keep distinct structure kinds and
+	// distinct relation types from collapsing into one dataset row.
+	type ekey struct{ name, typ, ckwd string }
+	type rkey struct{ from, typ, to, ckwd string }
 	entByKey := make(map[ekey]*StructureBucket, 16)
 	relByKey := make(map[rkey]*StructureBucket, 16)
+	// The authoritative Python (dataset_structure_merger._do_build) merges EVERY
+	// structure-kind doc row unconditionally — dataset scope is driven by the
+	// task type (structure_graph/timeline/structure_mindmap), NOT by a template
+	// Config["dataset_merge"] flag (that was a stale runner.py concept). So
+	// structure/mindmap entity/relation products always enter the dataset merge.
 	for _, p := range products {
-		if p.Variant != kccommon.VariantStructure {
+		if p.Variant != kccommon.VariantStructure && p.Variant != kccommon.VariantMindmap {
 			continue
 		}
+		// Dataset rows carry the SAME compile_kwd as the doc rows (the inferred
+		// compile type / autotype: "hypergraph"/"timeline"/"mindmap"/"list"/…),
+		// mirroring Python dataset_structure_merger._do_build which passes the doc
+		// row's compile_kwd through verbatim. The template kind (p.Kind, restored
+		// from compilation_template_kind_kwd) is stored on the SEPARATE
+		// compilation_template_kind_kwd field and is what read/delete paths match
+		// on — NOT compile_kwd. Do not rewrite compile_kwd to the template kind:
+		// that would diverge from Python (which never does) and split doc vs
+		// dataset rows.
+		ckwd := metaString(p.Meta, "compile_kwd")
+		if ckwd == "" {
+			ckwd = compileKwdForVariant(p.Variant)
+		}
 		kind := metaString(p.Meta, "kind")
 		from := metaString(p.Meta, "from")
 		to := metaString(p.Meta, "to")
@@ -1047,10 +1070,17 @@ func (c *Consumer) mergeStructureDataset(ctx context.Context, tenant, kb string,
 			if from == "" || to == "" {
 				continue
 			}
-			k := rkey{from: strings.ToLower(from), to: strings.ToLower(to)}
+			relType := metaString(p.Meta, "relation_type")
+			if relType == "" {
+				relType = metaString(p.Meta, "type")
+			}
+			if relType == "" {
+				relType = "related"
+			}
+			k := rkey{from: strings.ToLower(from), typ: strings.ToLower(relType), to: strings.ToLower(to), ckwd: ckwd}
 			b := relByKey[k]
 			if b == nil {
-				b = &StructureBucket{Name: from + " -> " + to, Type: "relation", FromEntity: from, ToEntity: to}
+				b = &StructureBucket{Name: from + " -> " + to, Type: "relation", FromEntity: from, ToEntity: to, CompileKwd: ckwd, TemplateID: p.TemplateID, TemplateKind: p.Kind, RelationType: relType}
 				relByKey[k] = b
 			}
 			appendBucket(b, p)
@@ -1065,10 +1095,10 @@ func (c *Consumer) mergeStructureDataset(ctx context.Context, tenant, kb string,
 		if name == "" {
 			continue
 		}
-		k := ekey{name: strings.ToLower(name), typ: typ}
+		k := ekey{name: strings.ToLower(name), typ: typ, ckwd: ckwd}
 		b := entByKey[k]
 		if b == nil {
-			b = &StructureBucket{Name: name, Type: typ}
+			b = &StructureBucket{Name: name, Type: typ, CompileKwd: ckwd, TemplateID: p.TemplateID, TemplateKind: p.Kind}
 			entByKey[k] = b
 		}
 		appendBucket(b, p)
@@ -1080,6 +1110,11 @@ func (c *Consumer) mergeStructureDataset(ctx context.Context, tenant, kb string,
 	for _, b := range relByKey {
 		buckets = append(buckets, *b)
 	}
+	common.Info("knowledge_compile: mergeStructureDataset buckets",
+		zap.String("kb_id", kb),
+		zap.Int("entities", len(entByKey)),
+		zap.Int("relations", len(relByKey)),
+		zap.Int("total_buckets", len(buckets)))
 	if len(buckets) == 0 {
 		return nil
 	}
@@ -1097,14 +1132,28 @@ func (c *Consumer) mergeStructureDataset(ctx context.Context, tenant, kb string,
 // element-wise running mean (review issue 13). VecCount tracks how many vectors
 // have been folded so the mean is order-independent.
 func appendBucket(b *StructureBucket, p kccommon.Product) {
-	if strings.TrimSpace(p.Content) != "" {
+	// The product's Content is the doc row's full content_with_weight JSON
+	// (e.g. {"category":"Person","description":"…","name":"…","type":"entity"}),
+	// NOT the plain-text description. Extract the "description" field so the
+	// dataset row's description stays a plain-text string (mirror Python
+	// _struct_merge_graph_entities, which folds the entity description, not the
+	// whole payload). Fall back to Content only when it is not a JSON object.
+	if desc := structureProductDescription(p.Content); desc != "" {
 		if b.Description != "" {
 			b.Description += "\n"
 		}
-		b.Description += strings.TrimSpace(p.Content)
+		b.Description += desc
 	}
 	b.SourceDocIDs = appendUnique(b.SourceDocIDs, []string{p.DocID})
 	b.SourceChunkIDs = appendUnique(b.SourceChunkIDs, metaStringSlice(p.Meta, "source_chunk_ids"))
+	// mention_count_int: sum the per-entity mention counts (Python
+	// _struct_merge_graph_entities sums mention_count across the merged entities).
+	// Each entity product carries mention_count ≥ 1 (structure compile.go L231);
+	// mindmap entities carry none, so they contribute a default of 0 and are
+	// simply not stamped (mention_count_int is omitted when 0).
+	if mc, ok := metaInt(p.Meta, "mention_count"); ok && mc > 0 {
+		b.MentionCount += int(mc)
+	}
 	if len(p.Vector) > 0 {
 		b.VecCount++
 		if len(b.Vector) == 0 {
@@ -1122,6 +1171,33 @@ func appendBucket(b *StructureBucket, p kccommon.Product) {
 	}
 }
 
+// structureProductDescription extracts the plain-text description from a structure
+// product's Content. In production Content is the doc row's content_with_weight
+// JSON ({"description":"…","name":"…","type":"…"}), so we parse it and return the
+// "description" field — the whole payload must NOT leak into the dataset row's
+// description (that is the bug: projectEntity then renders the raw JSON object).
+// When Content is NOT a JSON object (plain text, legacy/unit-test rows), it is
+// returned verbatim so existing folded-description behavior is preserved.
+func structureProductDescription(content string) string {
+	content = strings.TrimSpace(content)
+	if content == "" {
+		return ""
+	}
+	if content[0] == '{' {
+		var m map[string]any
+		if err := json.Unmarshal([]byte(content), &m); err == nil {
+			if d, ok := m["description"].(string); ok {
+				if s := strings.TrimSpace(d); s != "" {
+					return s
+				}
+			}
+			// JSON object without a plain-text description: nothing to fold.
+			return ""
+		}
+	}
+	return content
+}
+
 // appendUnique appends only values not already present, preserving order.
 func appendUnique(dst, values []string) []string {
 	seen := make(map[string]bool, len(dst)+len(values))
diff --git a/internal/ingestion/knowledge_compile/reader.go b/internal/ingestion/knowledge_compile/reader.go
index 6861ba35db..7a75e52c96 100644
--- a/internal/ingestion/knowledge_compile/reader.go
+++ b/internal/ingestion/knowledge_compile/reader.go
@@ -79,12 +79,16 @@ var compiledSelectFields = []string{
 	"name_kwd", "entity_type_kwd", "from_entity_kwd", "to_entity_kwd",
 	"slug_kwd", "type",
 	"kc_kind", "create_timestamp_flt", "create_time",
-	"compilation_template_kind_kwd",
+	"compilation_template_kind_kwd", "compilation_template_ids",
 	// The product kind discriminator for structure/tree: the component stores it
 	// under knowledge_graph_kwd (structure: graph/entity/relation) / raptor_kwd
 	// (tree: root/summary). Without these the reader cannot restore Meta["kind"]
 	// and the dataset-nav dispatch would skip structure/tree products (B2).
 	"knowledge_graph_kwd", "raptor_kwd",
+	// mention_count_int round-trips the entity mention count for reprojection.
+	// (relation type lives in the content_with_weight payload, matching Python —
+	// there is NO relation_type_kwd column.)
+	"mention_count_int",
 }
 
 // wikiSelectFields are the additional columns a wiki page carries (beyond
@@ -208,9 +212,21 @@ func productFromChunkMap(c map[string]interface{}, tenant string, expect kccommo
 	if err != nil || mapped != expect {
 		return kccommon.Product{}, false
 	}
+	// Round-trip the raw compile_kwd (the inferred compile type / autotype:
+	// list/set/hypergraph/timeline/mindmap/…) so the dataset-level merge can
+	// stamp the SAME value on the dataset row as the doc row (Python _do_build
+	// carries the doc row's compile_kwd through verbatim). Without this, the
+	// merge falls back to compileKwdForVariant ("structure"/"mindmap"), which
+	// diverges from the doc row's autotype ("hypergraph"/"timeline").
 	merged := isAvailable(c["available_int"])
 
 	meta := map[string]any{}
+	// Preserve the raw compile_kwd (autotype) for the dataset merge (see the
+	// round-trip note above). A non-string scalar from the engine is normalized
+	// via asString, matching the variant reverse-map at the top of this func.
+	if v := asString(c["compile_kwd"]); v != "" {
+		meta["compile_kwd"] = v
+	}
 	if v, ok := c["name_kwd"].(string); ok && v != "" {
 		meta["name"] = v
 	}
@@ -225,6 +241,9 @@ func productFromChunkMap(c map[string]interface{}, tenant string, expect kccommo
 		meta["to"] = v
 		meta["kind"] = "relation"
 	}
+	if v, ok := metaInt(c, "mention_count_int"); ok {
+		meta["mention_count"] = v
+	}
 	if v, ok := c["slug_kwd"].(string); ok && v != "" {
 		// slug_kwd is the full "<page_type>/<slug>" form (Python writer
 		// contract); reconstruct it verbatim so the round-trip stays full-form.
@@ -310,16 +329,26 @@ func productFromChunkMap(c map[string]interface{}, tenant string, expect kccommo
 	// so callers (e.g. RebuildDataset's variant recovery, B1a) can map it back
 	// via KindToVariant instead of re-deriving from the ambiguous compile_kwd.
 	kind := asString(c["compilation_template_kind_kwd"])
+	// Restore the compilation template id (from compilation_template_ids) so the
+	// dataset merge can bucket structure rows per template and read/delete paths
+	// can filter by it. A row should carry exactly one template id; if it carries
+	// more than one the first is used (multi-template rows are a config error
+	// surfaced elsewhere).
+	templateID := ""
+	if ids := metaStringSlice(c, "compilation_template_ids"); len(ids) > 0 {
+		templateID = ids[0]
+	}
 	return kccommon.Product{
-		ID:       id,
-		DocID:    docID,
-		TenantID: tenant,
-		Variant:  expect,
-		Kind:     kind,
-		Content:  content,
-		Vector:   vec,
-		Meta:     meta,
-		Merged:   merged,
+		ID:         id,
+		DocID:      docID,
+		TenantID:   tenant,
+		Variant:    expect,
+		Kind:       kind,
+		TemplateID: templateID,
+		Content:    content,
+		Vector:     vec,
+		Meta:       meta,
+		Merged:     merged,
 	}, true
 }
 
diff --git a/internal/ingestion/knowledge_compile/structure_merge_test.go b/internal/ingestion/knowledge_compile/structure_merge_test.go
index 764a9b8b9c..ce1f5ada00 100644
--- a/internal/ingestion/knowledge_compile/structure_merge_test.go
+++ b/internal/ingestion/knowledge_compile/structure_merge_test.go
@@ -114,17 +114,102 @@ func TestMergeStructureDataset_RelationsNotDropped(t *testing.T) {
 	}
 }
 
+// TestMergeStructureDataset_DescriptionIsPlainText covers the description bug:
+// the product Content is the doc row's content_with_weight JSON, so the dataset
+// row's folded description must be the plain-text "description" field, NOT the raw
+// JSON object (which would leak the whole entity payload into the rendered graph).
+func TestMergeStructureDataset_DescriptionIsPlainText(t *testing.T) {
+	c := &Consumer{writer: &fakeWriter{}}
+	products := []kccommon.Product{
+		{Variant: kccommon.VariantStructure, DocID: "d1",
+			Content: `{"category":"Person","description":"汉桓帝，禁锢善类","name":"桓帝","type":"entity"}`,
+			Meta:    map[string]any{"name": "桓帝", "entity_type": "Person", "compile_kwd": "list", "source_chunk_ids": []string{"c1"}}},
+	}
+	if err := c.mergeStructureDataset(context.Background(), "t1", "kb1", products); err != nil {
+		t.Fatalf("mergeStructureDataset: %v", err)
+	}
+	fw := c.writer.(*fakeWriter)
+	if len(fw.buckets) != 1 {
+		t.Fatalf("want 1 bucket, got %d", len(fw.buckets))
+	}
+	got := fw.buckets[0].Description
+	if got != "汉桓帝，禁锢善类" {
+		t.Errorf("description = %q, want plain-text \"汉桓帝，禁锢善类\" (not the raw JSON payload)", got)
+	}
+	if strings.Contains(got, "{") || strings.Contains(got, "category") {
+		t.Errorf("description leaked the JSON payload: %q", got)
+	}
+}
+
+// TestMergeStructureDataset_CompileKwdIsAutotypeNotTemplateKind covers the
+// option-A alignment: the dataset row's compile_kwd is the doc row's inferred
+// compile type (autotype, e.g. "hypergraph"/"mindmap"), NOT the template kind.
+// The template kind travels on the separate TemplateKind field (stamped to
+// compilation_template_kind_kwd by WriteMergedStructure), which is what read/
+// delete paths match on. This mirrors Python _do_build (compile_kwd passes
+// through verbatim) + get_dataset_structure (matches template kind).
+func TestMergeStructureDataset_CompileKwdIsAutotypeNotTemplateKind(t *testing.T) {
+	c := &Consumer{writer: &fakeWriter{}}
+	products := []kccommon.Product{
+		{Variant: kccommon.VariantStructure, DocID: "d1", Kind: "knowledge_graph", TemplateID: "tpl-graph",
+			Content: "Engine desc",
+			Meta:    map[string]any{"name": "Engine", "entity_type": "component", "compile_kwd": "hypergraph", "source_chunk_ids": []string{"c1"}}},
+		{Variant: kccommon.VariantMindmap, DocID: "d2", Kind: "mind_map", TemplateID: "tpl-mindmap",
+			Content: "Fuel desc",
+			Meta:    map[string]any{"name": "Fuel", "entity_type": "substance", "compile_kwd": "mindmap", "source_chunk_ids": []string{"c2"}}},
+	}
+	if err := c.mergeStructureDataset(context.Background(), "t1", "kb1", products); err != nil {
+		t.Fatalf("mergeStructureDataset: %v", err)
+	}
+	fw := c.writer.(*fakeWriter)
+	if len(fw.buckets) != 2 {
+		t.Fatalf("want 2 buckets, got %d", len(fw.buckets))
+	}
+	for i := range fw.buckets {
+		b := fw.buckets[i]
+		switch b.Name {
+		case "Engine":
+			if b.CompileKwd != "hypergraph" {
+				t.Errorf("Engine compile_kwd = %q, want autotype \"hypergraph\" (not template kind)", b.CompileKwd)
+			}
+			if b.TemplateKind != "knowledge_graph" {
+				t.Errorf("Engine TemplateKind = %q, want \"knowledge_graph\"", b.TemplateKind)
+			}
+			if b.TemplateID != "tpl-graph" {
+				t.Errorf("Engine TemplateID = %q, want \"tpl-graph\"", b.TemplateID)
+			}
+		case "Fuel":
+			if b.CompileKwd != "mindmap" {
+				t.Errorf("Fuel compile_kwd = %q, want autotype \"mindmap\" (not template kind)", b.CompileKwd)
+			}
+			if b.TemplateKind != "mind_map" {
+				t.Errorf("Fuel TemplateKind = %q, want \"mind_map\"", b.TemplateKind)
+			}
+			if b.TemplateID != "tpl-mindmap" {
+				t.Errorf("Fuel TemplateID = %q, want \"tpl-mindmap\"", b.TemplateID)
+			}
+		}
+	}
+}
+
 // TestDatasetLevelStructureID_StableAndCaseInsensitive covers G1: the id is
 // deterministic and case-insensitive on name so merges hit the same row.
 func TestDatasetLevelStructureID_StableAndCaseInsensitive(t *testing.T) {
-	a := datasetLevelStructureID("t1", "kb1", "Engine", "component")
-	b := datasetLevelStructureID("t1", "kb1", "engine", "component")
+	a := datasetLevelStructureID("t1", "kb1", "Engine", "component", "timeline", "")
+	b := datasetLevelStructureID("t1", "kb1", "engine", "component", "timeline", "")
 	if a != b {
 		t.Errorf("structure id should be case-insensitive on name: %q vs %q", a, b)
 	}
-	if a == datasetLevelStructureID("t1", "kb1", "Fuel", "component") {
+	if a == datasetLevelStructureID("t1", "kb1", "Fuel", "component", "timeline", "") {
 		t.Errorf("different names must yield different ids")
 	}
+	if a == datasetLevelStructureID("t1", "kb1", "Engine", "component", "mindmap", "") {
+		t.Errorf("different compile kinds must yield different ids")
+	}
+	if datasetLevelStructureID("t1", "kb1", "A -> B", "relation", "graph", "causes") ==
+		datasetLevelStructureID("t1", "kb1", "A -> B", "relation", "graph", "contradicts") {
+		t.Errorf("different relation types between the same endpoints must yield different ids")
+	}
 }
 
 // TestKwdToVariant_MapsStructureSubKinds covers B1a: structure doc-level products
@@ -182,6 +267,11 @@ func TestProductFromChunkMap_RestoresStructureTreeKind(t *testing.T) {
 	if kind, _ := sp.Meta["kind"].(string); kind != "graph" {
 		t.Errorf("structure Meta.kind = %q, want graph (so nav dispatch can pick it)", kind)
 	}
+	// Round-trip: the raw compile_kwd (autotype) must be preserved in Meta so the
+	// dataset merge stamps the SAME value on the dataset row as the doc row.
+	if ckwd, _ := sp.Meta["compile_kwd"].(string); ckwd != "list" {
+		t.Errorf("structure Meta.compile_kwd = %q, want autotype \"list\" (not \"structure\")", ckwd)
+	}
 
 	// tree root product: kind stored in raptor_kwd.
 	treeRow := map[string]interface{}{
diff --git a/internal/ingestion/knowledge_compile/writer.go b/internal/ingestion/knowledge_compile/writer.go
index 88cc9514ef..1d2721e568 100644
--- a/internal/ingestion/knowledge_compile/writer.go
+++ b/internal/ingestion/knowledge_compile/writer.go
@@ -101,6 +101,28 @@ type StructureBucket struct {
 	VecCount       int    // number of vectors folded into Vector (for true mean)
 	FromEntity     string // relation only
 	ToEntity       string // relation only
+	// CompileKwd is the raw compile keyword (the inferred compile type / autotype,
+	// e.g. "hypergraph", "timeline", "mindmap", "list") that produced this bucket.
+	// It is stamped on the stored row's compile_kwd so distinct structure kinds
+	// never collide in the same dataset namespace (plan §1.1). It matches the doc
+	// row's own compile_kwd — Python _do_build carries the doc row's compile_kwd
+	// verbatim onto the dataset row, it does NOT rewrite it to the template kind.
+	CompileKwd string
+	// TemplateID is the compilation template id (compilation_template_ids[0]) that
+	// produced this bucket. Stamped on the dataset row so read/delete paths can
+	// filter per template (mirror Python get_dataset_structure).
+	TemplateID string
+	// TemplateKind is the authoritative template kind (compilation_template_kind_kwd,
+	// e.g. "knowledge_graph", "mind_map", "timeline"). This — NOT compile_kwd — is
+	// the field read/delete paths match on for the dataset-structure kind
+	// (mirror Python get_dataset_structure._discover_scope_templates, which
+	// matches _resolve_dataset_structure_kind against compilation_template_kind_kwd).
+	TemplateKind string
+	// RelationType is the relation type (Python default "related"), persisted as
+	// relation_type_kwd and part of the relation bucket/ID identity.
+	RelationType string
+	// MentionCount is the entity mention count (mention_count_int); 0 when unset.
+	MentionCount int
 }
 
 // engineWriter persists dataset-level merged products through the global
@@ -111,6 +133,33 @@ type engineWriter struct {
 	eng engine.DocEngine
 }
 
+// datasetStructureSupported reports whether the running doc engine can filter
+// the dataset-structure fields (knowledge_graph_kwd + scope_kwd + raw
+// compile_kwd) this feature writes/deletes. Only infinity and elasticsearch
+// support them today; OceanBase/SeekDB/SereneDB have explicit schemas that lack
+// these filter keys and would reject the query or silently drop unknown fields.
+// The guard is checked at every dataset-structure write/delete/rebuild entry so
+// those engines never leave partial state or hit an unknown-filter error (plan §5).
+func datasetStructureSupported() bool {
+	switch engine.GetEngineType() {
+	case "infinity", "elasticsearch":
+		return true
+	case "":
+		// Engine not initialized (unit tests inject a fake engine directly via
+		// engineWriter.eng). The guard is only meaningful against a real engine
+		// type, so an empty type is treated as supported.
+		return true
+	default:
+		return false
+	}
+}
+
+// errDatasetStructureUnsupported returns an error (not a silent no-op) naming
+// the engine when a dataset-structure operation runs on an unsupported engine.
+func errDatasetStructureUnsupported() error {
+	return fmt.Errorf("dataset structure graph unsupported on doc engine %q", engine.GetEngineType())
+}
+
 // writeMergedBatchSize bounds how many rows each parallel InsertChunks call
 // carries, so the DocEngine write fan-out stays granular under the shared pool.
 const writeMergedBatchSize = 200
@@ -202,13 +251,18 @@ func (w engineWriter) WriteMerged(ctx context.Context, tenant, kb string, produc
 
 // WriteMergedStructure writes the dataset-level structure merged rows for a KB
 // (G1/G4). Each StructureBucket is a scope_kwd="dataset" row with a stable
-// dataset-level id keyed on (name, type), the folded description, the union of
-// source docs/chunks, and the bucket vector. Rows are available_int=1 so the
-// dataset-level structure index is searchable, and compile_kwd="structure".
+// dataset-level id keyed on (name, type, raw compile kind), the folded
+// description, the union of source docs/chunks, and the bucket vector. Rows are
+// available_int=1 so the dataset-level structure index is searchable; the raw
+// compile kind (timeline/graph/mindmap) is stamped on compile_kwd and the
+// entity/relation discriminator on knowledge_graph_kwd.
 func (w engineWriter) WriteMergedStructure(ctx context.Context, tenant, kb string, buckets []StructureBucket) error {
 	if len(buckets) == 0 {
 		return nil
 	}
+	if !datasetStructureSupported() {
+		return errDatasetStructureUnsupported()
+	}
 	eng := w.eng
 	if eng == nil {
 		eng = engine.Get()
@@ -229,7 +283,7 @@ func (w engineWriter) WriteMergedStructure(ctx context.Context, tenant, kb strin
 			if b.Name == "" {
 				continue
 			}
-			ids = append(ids, datasetLevelStructureID(tenant, kb, b.Name, b.Type))
+			ids = append(ids, datasetLevelStructureID(tenant, kb, b.Name, b.Type, b.CompileKwd, b.RelationType))
 		}
 		if len(ids) > 0 {
 			res, err := eng.Search(ctx, &types.SearchRequest{
@@ -263,43 +317,128 @@ func (w engineWriter) WriteMergedStructure(ctx context.Context, tenant, kb strin
 		if b.Name == "" {
 			continue
 		}
-		bid := datasetLevelStructureID(tenant, kb, b.Name, b.Type)
+		bid := datasetLevelStructureID(tenant, kb, b.Name, b.Type, b.CompileKwd, b.RelationType)
 		// Union the current batch's sources with any already-accumulated ones.
 		if prev, ok := existing[bid]; ok {
 			b.SourceDocIDs = appendUnique(b.SourceDocIDs, prev.SourceDocIDs)
 			b.SourceChunkIDs = appendUnique(b.SourceChunkIDs, prev.SourceChunkIDs)
 		}
+		ckwd := b.CompileKwd
+		if ckwd == "" {
+			ckwd = compileKwdStructure
+		}
+		// content_with_weight is a JSON payload, matching Python (and the existing
+		// wiki projection writer below): the structured fields (from/to/type for
+		// relations, name/type for entities) live INSIDE the payload, while
+		// from/to are also copied to from_entity_kwd/to_entity_kwd top-level
+		// columns for filtering. There is NO relation_type_kwd column — the
+		// relation type is carried only in the payload, exactly as Python does.
+		var payloadMap map[string]any
+		if b.FromEntity != "" || b.ToEntity != "" {
+			relType := b.RelationType
+			if relType == "" {
+				relType = "related"
+			}
+			payloadMap = map[string]any{
+				"from":        b.FromEntity,
+				"to":          b.ToEntity,
+				"type":        relType,
+				"description": desc,
+			}
+		} else {
+			typ := b.Type
+			if typ == "" {
+				typ = "other"
+			}
+			payloadMap = map[string]any{
+				"name":        b.Name,
+				"type":        typ,
+				"description": desc,
+			}
+		}
+		payloadBytes, err := json.Marshal(payloadMap)
+		if err != nil {
+			return err
+		}
+		payload := string(payloadBytes)
 		row := map[string]interface{}{
-			// Stable dataset-level id keyed on the (name, type) or (from, to) bucket.
+			// Stable dataset-level id keyed on the (name, type) or (from, to)
+			// bucket plus the raw compile kind.
 			"id":                   bid,
 			"doc_id":               kb,
 			"tenant_id":            tenant,
 			"kb_id":                kb,
 			"available_int":        1,
-			"compile_kwd":          compileKwdStructure,
+			"compile_kwd":          ckwd,
 			"scope_kwd":            "dataset",
-			"content_with_weight":  desc,
-			"kc_payload":           desc,
+			"content_with_weight":  payload,
+			"kc_payload":           payload,
 			"source_doc_ids":       b.SourceDocIDs,
 			"source_chunk_ids":     b.SourceChunkIDs,
 			"create_time":          now.Format("2006-01-02 15:04:05"),
 			"create_timestamp_flt": float64(now.Unix()),
 		}
+		// Stamp the authoritative template identity so read/delete paths can match
+		// the dataset-structure kind by compilation_template_kind_kwd (mirror Python
+		// get_dataset_structure._discover_scope_templates), independent of the
+		// autotype-valued compile_kwd above.
+		if b.TemplateKind != "" {
+			row["compilation_template_kind_kwd"] = b.TemplateKind
+		}
+		if b.TemplateID != "" {
+			row["compilation_template_ids"] = []string{b.TemplateID}
+		}
 		if b.FromEntity != "" || b.ToEntity != "" {
 			// relation row: carries from/to entities; kind=relation, no name_kwd.
+			row["knowledge_graph_kwd"] = "relation"
 			row["type_kwd"] = "relation"
 			row["from_entity_kwd"] = b.FromEntity
 			row["to_entity_kwd"] = b.ToEntity
 		} else {
+			row["knowledge_graph_kwd"] = "entity"
 			row["type_kwd"] = "entity"
 			row["name_kwd"] = b.Name
 			row["entity_type_kwd"] = b.Type
+			if b.MentionCount > 0 {
+				row["mention_count_int"] = b.MentionCount
+			}
 		}
 		if len(b.Vector) > 0 {
 			row["q_"+fmt.Sprintf("%d", len(b.Vector))+"_vec"] = f32ToF64Slice(b.Vector)
 		}
 		rows = append(rows, row)
 	}
+	// Write one kg_build_meta build-marker row per raw compile kind (the bucket
+	// model is keyed by raw kind; template-id granularity is a follow-up when the
+	// bucket key gains a template dimension). The marker is available_int=0 and
+	// carries create_timestamp_flt as its timestamp (build_timestamp_flt is a
+	// Python _META_ROW_KWD legacy field NOT present in the Infinity/ES/OS schemas,
+	// so writing it would fail with an undefined-column error — see review). It is
+	// a write/delete-side marker — GET discovery does NOT read it (it scans
+	// knowledge_graph_kwd=["entity"] rows instead, per §6).
+	seenKwd := map[string]bool{}
+	for _, b := range buckets {
+		ckwd := b.CompileKwd
+		if ckwd == "" {
+			ckwd = compileKwdStructure
+		}
+		if seenKwd[ckwd] {
+			continue
+		}
+		seenKwd[ckwd] = true
+		rows = append(rows, map[string]interface{}{
+			"id":                   "dataset_build_meta_" + hashStr(tenant+"\x00"+kb+"\x00"+ckwd),
+			"doc_id":               kb,
+			"tenant_id":            tenant,
+			"kb_id":                kb,
+			"available_int":        0,
+			"compile_kwd":          ckwd,
+			"scope_kwd":            "dataset",
+			"knowledge_graph_kwd":  "kg_build_meta",
+			"create_time":          now.Format("2006-01-02 15:04:05"),
+			"create_timestamp_flt": float64(now.Unix()),
+		})
+	}
 	if len(rows) == 0 {
 		return nil
 	}
@@ -329,6 +468,9 @@ func (w engineWriter) DeleteStructureForDocs(ctx context.Context, tenant, kb str
 	if len(deletedDocIDs) == 0 {
 		return nil
 	}
+	if !datasetStructureSupported() {
+		return errDatasetStructureUnsupported()
+	}
 	eng := w.eng
 	if eng == nil {
 		eng = engine.Get()
@@ -346,14 +488,25 @@ func (w engineWriter) DeleteStructureForDocs(ctx context.Context, tenant, kb str
 	// surviving silently (review Minor).
 	const pageSize = 500
 	var ghostIDs []string
+	// Raw compile kinds whose entity/relation rows were declared ghosts; used to
+	// drop a now-empty kind's kg_build_meta build marker after cleanup.
+	affectedKinds := map[string]bool{}
 	for offset := 0; ; offset += pageSize {
 		res, err := eng.Search(ctx, &types.SearchRequest{
 			IndexNames:   []string{baseName},
 			KbIDs:        []string{kb},
-			SelectFields: []string{"id", "source_doc_ids"},
-			Filter:       map[string]interface{}{"kb_id": kb, "scope_kwd": "dataset", "compile_kwd": compileKwdStructure},
-			Offset:       offset,
-			Limit:        pageSize,
+			SelectFields: []string{"id", "source_doc_ids", "compile_kwd"},
+			// Match dataset-scope entity/relation rows across ALL structure kinds
+			// (timeline/graph/session_graph/mindmap), which now each stamp their
+			// raw compile_kwd; knowledge_graph_kwd ∈ {entity,relation} + scope_kwd
+			// =dataset is the kind-agnostic predicate (plan §1, §4.2).
+			Filter: map[string]interface{}{
+				"kb_id":               kb,
+				"scope_kwd":           "dataset",
+				"knowledge_graph_kwd": []string{"entity", "relation"},
+			},
+			Offset: offset,
+			Limit:  pageSize,
 		})
 		if err != nil {
 			return fmt.Errorf("structure ghost scan: %w", err)
@@ -379,6 +532,9 @@ func (w engineWriter) DeleteStructureForDocs(ctx context.Context, tenant, kb str
 			}
 			if allGone {
 				ghostIDs = append(ghostIDs, id)
+				if ckwd, _ := c["compile_kwd"].(string); ckwd != "" {
+					affectedKinds[ckwd] = true
+				}
 			}
 		}
 		if len(res.Chunks) < pageSize {
@@ -388,18 +544,51 @@ func (w engineWriter) DeleteStructureForDocs(ctx context.Context, tenant, kb str
 	if len(ghostIDs) == 0 {
 		return nil
 	}
-	_, err := eng.DeleteChunks(ctx, map[string]interface{}{"id": ghostIDs, "kb_id": kb}, baseName, kb)
-	if err != nil {
+	if _, err := eng.DeleteChunks(ctx, map[string]interface{}{"id": ghostIDs, "kb_id": kb}, baseName, kb); err != nil {
 		return fmt.Errorf("structure ghost cleanup: %w", err)
 	}
+	// Drop the kg_build_meta build marker for any raw kind that no longer has an
+	// entity/relation row (plan §3.1.1 step 4).
+	for ckwd := range affectedKinds {
+		res, err := eng.Search(ctx, &types.SearchRequest{
+			IndexNames:   []string{baseName},
+			KbIDs:        []string{kb},
+			SelectFields: []string{"id"},
+			Filter: map[string]interface{}{
+				"kb_id":               kb,
+				"scope_kwd":           "dataset",
+				"compile_kwd":         ckwd,
+				"knowledge_graph_kwd": []string{"entity", "relation"},
+			},
+			Limit: 1,
+		})
+		if err != nil {
+			return fmt.Errorf("structure meta check (kind %s): %w", ckwd, err)
+		}
+		if len(res.Chunks) > 0 {
+			continue // still has entity/relation rows; keep the marker
+		}
+		if _, err := eng.DeleteChunks(ctx, map[string]interface{}{
+			"kb_id":               kb,
+			"scope_kwd":           "dataset",
+			"compile_kwd":         ckwd,
+			"knowledge_graph_kwd": "kg_build_meta",
+		}, baseName, kb); err != nil {
+			return fmt.Errorf("structure meta cleanup (kind %s): %w", ckwd, err)
+		}
+	}
 	return nil
 }
 
 // datasetLevelStructureID builds the stable dataset-level id for a structure
-// bucket, keyed on (name, type). It must be deterministic so an incremental
-// merge read-modify-writes the same row (and a rebuild clean removes it).
-func datasetLevelStructureID(tenant, kb, name, typ string) string {
-	return "dataset_structure_" + hashStr(tenant+"\x00"+kb+"\x00"+strings.ToLower(name)+"\x00"+typ)
+// bucket, keyed on (name, type, compile kind, relation type). It must be
+// deterministic so an incremental merge read-modify-writes the same row (and a
+// rebuild clean removes it). Including the raw compile kind keeps
+// timeline/graph/mindmap buckets from colliding in the same dataset namespace;
+// including the relation type keeps two relation types between the same endpoints
+// (e.g. "causes" vs "contradicts") from colliding into one id (review fix).
+func datasetLevelStructureID(tenant, kb, name, typ, compileKwd, relationType string) string {
+	return "dataset_structure_" + hashStr(tenant+"\x00"+kb+"\x00"+strings.ToLower(name)+"\x00"+typ+"\x00"+compileKwd+"\x00"+strings.ToLower(relationType))
 }
 
 // f32ToF64Slice converts a float32 vector to float64 for the engine's dense
@@ -937,7 +1126,13 @@ func (w engineWriter) DeleteMergedForVariant(ctx context.Context, tenant, kb str
 		// Full-set clean (B1b): everything the consumer manages. Structure
 		// dataset rows are tagged scope_kwd="dataset" (not a fixed compile_kwd),
 		// so the full clean deletes by kb_id + compile_kwd IN (the fixed-kwd
-		// buckets) OR scope_kwd="dataset".
+		// buckets) OR scope_kwd="dataset". The scope_kwd="dataset" sweep requires
+		// the dataset-structure filter keys, so it is guarded like the per-variant
+		// structure branch (review fix: this is the highest-impact destructive
+		// path and must fail loudly on unsupported engines).
+		if !datasetStructureSupported() {
+			return errDatasetStructureUnsupported()
+		}
 		_, err := eng.DeleteChunks(ctx, map[string]interface{}{
 			"kb_id": kb,
 			"compile_kwd": []string{
@@ -979,17 +1174,23 @@ func (w engineWriter) DeleteMergedForVariant(ctx context.Context, tenant, kb str
 			}, baseName, kb); err != nil {
 				return fmt.Errorf("delete merged (wiki): %w", err)
 			}
-		case kccommon.VariantStructure:
-			// structure dataset rows are scope_kwd="dataset" + compile_kwd=
-			// "structure". The compile_kwd is required: wiki merged rows ALSO carry
-			// scope_kwd="dataset" (W5), so a scope-only sweep would wrongly delete
-			// wiki merged rows too (review Major).
+		case kccommon.VariantStructure, kccommon.VariantMindmap:
+			if !datasetStructureSupported() {
+				return errDatasetStructureUnsupported()
+			}
+			// structure/mindmap dataset rows are scope_kwd="dataset" +
+			// knowledge_graph_kwd ∈ {entity,relation,kg_build_meta} with a raw
+			// compile_kwd (timeline/graph/session_graph/mindmap). knowledge_graph_kwd
+			// is required: wiki merged rows ALSO carry scope_kwd="dataset" (W5), so
+			// a scope-only sweep would wrongly delete wiki merged rows too (review
+			// Major). kg_build_meta (the build marker) is deleted together with the
+			// entity/relation rows.
 			if _, err := eng.DeleteChunks(ctx, map[string]interface{}{
-				"kb_id":       kb,
-				"scope_kwd":   "dataset",
-				"compile_kwd": []string{compileKwdStructure},
+				"kb_id":               kb,
+				"scope_kwd":           "dataset",
+				"knowledge_graph_kwd": []string{"entity", "relation", "kg_build_meta"},
 			}, baseName, kb); err != nil {
-				return fmt.Errorf("delete merged (structure): %w", err)
+				return fmt.Errorf("delete merged (structure/mindmap): %w", err)
 			}
 		case kccommon.VariantTree:
 			// tree/nav rows are compile_kwd="dataset_nav" with available_int=0;
@@ -1000,8 +1201,6 @@ func (w engineWriter) DeleteMergedForVariant(ctx context.Context, tenant, kb str
 			}, baseName, kb); err != nil {
 				return fmt.Errorf("delete merged (nav): %w", err)
 			}
-		case kccommon.VariantMindmap:
-			// mindmap has no dataset-level merged rows in the consumer path
 		}
 	}
 	return nil
diff --git a/internal/service/dataset_artifact_service.go b/internal/service/dataset_artifact_service.go
index 0ef4ca3744..37ad7cd953 100644
--- a/internal/service/dataset_artifact_service.go
+++ b/internal/service/dataset_artifact_service.go
@@ -39,16 +39,6 @@ const (
 	CompileKwdSkillAll     = "skill_all"
 	CompileKwdDatasetNav   = "dataset_nav"
 	CompileKwdRaptorGraph  = "raptor_graph"
-
-	CompileKwdStructure          = "structure"
-	CompileKwdStructureIndex     = "structureIndex"
-	CompileKwdStructureEntity    = "structureEntity"
-	CompileKwdStructureRelation  = "structureRelation"
-	CompileKwdStructureCommunity = "structureCommunity"
-
-	FieldStructureIndexType = "structure_index_type"
-	FieldStructureKind      = "structure_kind"
-	FieldPageID             = "page_id"
 )
 
 // DatasetArtifactService reads knowledge-compilation artifacts (wiki pages,
@@ -550,75 +540,6 @@ func (s *DatasetArtifactService) ClearWiki(ctx context.Context, tenantID, datase
 	return deleted, nil
 }
 
-// StructureItem is a single compiled structure entry for a dataset.
-type StructureItem struct {
-	PageID             string `json:"page_id"`
-	StructureKind      string `json:"structure_kind"`
-	StructureIndexType string `json:"structure_index_type"`
-	Data               string `json:"data"`
-}
-
-// ListStructures returns the compiled structures of a dataset, filtered by
-// optional structure_kind and structure_index_type.
-func (s *DatasetArtifactService) ListStructures(ctx context.Context, tenantID, datasetID, structureKind, structureIndexType string) ([]StructureItem, int64, error) {
-	filter := map[string]interface{}{"compile_kwd": []string{CompileKwdStructure}}
-	if structureKind != "" {
-		filter[FieldStructureKind] = []string{structureKind}
-	}
-	if structureIndexType != "" {
-		filter[FieldStructureIndexType] = []string{structureIndexType}
-	}
-	chunks, total, err := s.searchCompiled(ctx, tenantID, datasetID, filter,
-		[]string{FieldPageID, FieldStructureKind, FieldStructureIndexType, "content_with_weight"}, 0, 10000, nil)
-	if err != nil {
-		return nil, 0, err
-	}
-	items := make([]StructureItem, 0, len(chunks))
-	for _, c := range chunks {
-		items = append(items, StructureItem{
-			PageID:             firstStringValue(c[FieldPageID]),
-			StructureKind:      firstStringValue(c[FieldStructureKind]),
-			StructureIndexType: firstStringValue(c[FieldStructureIndexType]),
-			Data:               firstStringValue(c["content_with_weight"]),
-		})
-	}
-	return items, total, nil
-}
-
-// DeleteStructures deletes the compiled structures of a dataset, optionally
-// scoped by structure_kind and structure_index_type.
-func (s *DatasetArtifactService) DeleteStructures(ctx context.Context, tenantID, datasetID, structureKind, structureIndexType string) (int, error) {
-	docEngine := engine.Get()
-	if docEngine == nil {
-		return 0, fmt.Errorf("document engine is not initialized")
-	}
-	filter := map[string]interface{}{"compile_kwd": []string{CompileKwdStructure}}
-	if structureKind != "" {
-		filter[FieldStructureKind] = []string{structureKind}
-	}
-	if structureIndexType != "" {
-		filter[FieldStructureIndexType] = []string{structureIndexType}
-	}
-	chunks, _, err := s.searchCompiled(ctx, tenantID, datasetID, filter, []string{"id"}, 0, 10000, nil)
-	if err != nil {
-		return 0, err
-	}
-	if len(chunks) == 0 {
-		return 0, nil
-	}
-	ids := make([]string, 0, len(chunks))
-	for _, c := range chunks {
-		if id, ok := c["id"].(string); ok {
-			ids = append(ids, id)
-		}
-	}
-	cond := map[string]interface{}{"id": ids, "kb_id": datasetID}
-	if _, err := docEngine.DeleteChunks(ctx, cond, wikiIndexName(tenantID), datasetID); err != nil {
-		return 0, err
-	}
-	return len(ids), nil
-}
-
 // DeleteDocumentGraph deletes the structure graph of a single document.
 func (s *DatasetArtifactService) DeleteDocumentGraph(ctx context.Context, tenantID, datasetID, documentID string) (int, error) {
 	docEngine := engine.Get()
diff --git a/internal/service/dataset_structure_graph.go b/internal/service/dataset_structure_graph.go
index 77ed8f448a..caa557f38a 100644
--- a/internal/service/dataset_structure_graph.go
+++ b/internal/service/dataset_structure_graph.go
@@ -10,11 +10,13 @@ package service
 import (
 	"context"
 	"encoding/json"
+	"errors"
 	"fmt"
 	"regexp"
 	"sort"
 	"strings"
 
+	"gorm.io/gorm"
 	"ragflow/internal/dao"
 	"ragflow/internal/engine"
 	"ragflow/internal/engine/types"
@@ -468,8 +470,12 @@ func (s *DatasetArtifactService) buildBucket(ctx context.Context, tenantID, data
 		if err != nil {
 			return nil, nil, err
 		}
-		var entities []StructureGraphNode
-		var relations []StructureGraphRelation
+		// Initialize as empty (non-nil) slices so a bucket with entities but no
+		// relations serializes "relations": [] instead of null — the frontend
+		// adapters (adaptKnowledgeGraphToForceGraph et al.) call .filter() on
+		// relations without a null guard (mirror Python, which always returns []).
+		entities := make([]StructureGraphNode, 0)
+		relations := make([]StructureGraphRelation, 0)
 		for _, row := range fieldMap {
 			if !rowHasEnabledSource(row, excludedDocIDs) {
 				continue
@@ -530,7 +536,7 @@ func (s *DatasetArtifactService) buildBucket(ctx context.Context, tenantID, data
 	}
 	aNameTerms = sortedUnique(aNameTerms)
 
-	var relations []StructureGraphRelation
+	relations := make([]StructureGraphRelation, 0)
 	targetNamesLower := map[string]bool{}
 	if len(aNameTerms) > 0 {
 		cond := copyFilter(scope)
@@ -613,6 +619,59 @@ func compilationTemplateKind(kind string) string {
 	return k
 }
 
+// ErrInvalidStructureKind is returned when the request kind does not resolve to a
+// supported dataset-structure kind. Handlers use errors.Is to map it to
+// CodeArgumentError (400) while treating every other service error as a server
+// fault (500).
+var ErrInvalidStructureKind = errors.New("invalid structure kind")
+
+// datasetStructureSupported mirrors the writer's engine guard: only Infinity and
+// Elasticsearch resolve the dataset-structure filter keys (scope_kwd +
+// knowledge_graph_kwd). The writer keeps a private copy in the knowledge_compile
+// package; this service-side copy keeps the API delete path in agreement without
+// exporting an ingestion-internal helper across package boundaries.
+func datasetStructureSupported() bool {
+	switch engine.GetEngineType() {
+	case "infinity", "elasticsearch", "":
+		return true
+	default:
+		return false
+	}
+}
+
+// errDatasetStructureUnsupported returns a visible error naming the engine.
+func errDatasetStructureUnsupported() error {
+	return fmt.Errorf("dataset structure graph unsupported on doc engine %q", engine.GetEngineType())
+}
+
+// resolveDatasetStructureKind maps a user-facing dataset-structure kind to the
+// stored top-level kind (mirror Python _DATASET_STRUCTURE_KIND_ALIASES). It is
+// DELIBERATELY separate from compilationTemplateKind: that helper folds
+// knowledge_graph→timeline, which would merge distinct dataset kinds, and it
+// lacks the graph→knowledge_graph / mindmap→mind_map aliases (Python's
+// dataset_api_service.py L1803-1805 documents exactly why it does not reuse the
+// general normalizer). Returns "" for an invalid kind (caller maps that to
+// 400 ARGUMENT_ERROR, never "return all").
+func resolveDatasetStructureKind(kind string) string {
+	k := strings.ToLower(strings.TrimSpace(strings.ReplaceAll(kind, "-", "_")))
+	switch k {
+	case "graph", "knowledge_graph":
+		return "knowledge_graph"
+	case "mindmap", "mind_map":
+		// Align with Python _DATASET_STRUCTURE_KIND_ALIASES: resolve the
+		// user-facing "mindmap" to the stored compilation_template_kind_kwd value
+		// "mind_map" (the template kind, which is what read/delete paths match on).
+		return "mind_map"
+	case "timeline":
+		return "timeline"
+	case "session_essence":
+		return "session_essence"
+	case "session_graph":
+		return "session_graph"
+	}
+	return ""
+}
+
 // structureKindForBucket returns the normalized kind used for tree/page_index
 // hierarchy handling.
 func structureKindForBucket(kind string) string {
@@ -720,8 +779,10 @@ func (s *DatasetArtifactService) GetDocumentGraph(ctx context.Context, in Docume
 		return resp, nil
 	}
 
-	// normal mode: discover buckets from per-doc graph blob rows.
-	metaFields := []string{"compile_kwd", "compilation_template_ids", "compilation_template_kind_kwd"}
+	// normal mode: discover buckets from per-doc graph blob rows. "id" is
+	// required for the same reason as dataset discovery (Infinity only projects
+	// listed fields; graphRowSearch keys by id).
+	metaFields := []string{"id", "compile_kwd", "compilation_template_ids", "compilation_template_kind_kwd"}
 	metaRows, _, err := graphRowSearch(ctx, in.TenantID, in.DatasetID, metaFields,
 		map[string]interface{}{"doc_id": []string{in.DocumentID}, "knowledge_graph_kwd": []string{"graph"}}, nil, 0, 1000, nil)
 	if err != nil {
@@ -789,6 +850,197 @@ func containsStr(list []string, v string) bool {
 	return false
 }
 
+// DatasetStructureGraphInput is the parsed request for the dataset-scope
+// structure graph endpoint (GET/DELETE /datasets/:id/artifacts/structure).
+// Kind is REQUIRED (mirrors Python dataset_api.py:715): missing or invalid →
+// 400 ARGUMENT_ERROR. Wipe applies to DELETE: true deletes the dataset rows,
+// false only cancels the task (rows are left for the next rebuild to clean).
+type DatasetStructureGraphInput struct {
+	TenantID  string
+	DatasetID string
+	Kind      string
+	Wipe      bool
+}
+
+// DatasetStructureGraphResponse mirrors Python get_dataset_structure's
+// {"kind": ..., "templates": [...]}.
+type DatasetStructureGraphResponse struct {
+	Kind      string                           `json:"kind"`
+	Templates []DocumentStructureGraphTemplate `json:"templates"`
+}
+
+// GetDatasetStructure returns the dataset-scope structure graph for a resolved
+// kind, mirroring Python get_dataset_structure (dataset_api_service.py). Discovery
+// scans knowledge_graph_kwd=["entity"] dataset rows (scope_kwd="dataset") and
+// matches the resolved kind against the stamped compilation_template_kind_kwd —
+// NOT compile_kwd (compile_kwd holds the autotype "hypergraph"/"list"/"mindmap",
+// which is never the kind discriminator; Python _discover_scope_templates matches
+// _resolve_dataset_structure_kind against compilation_template_kind_kwd the same
+// way). It collects distinct template ids, then reads each template's dataset
+// entity/relation rows via buildBucket. It does NOT read kg_build_meta (write/
+// delete-side only).
+func (s *DatasetArtifactService) GetDatasetStructure(ctx context.Context, in DatasetStructureGraphInput) (*DatasetStructureGraphResponse, error) {
+	resolved := resolveDatasetStructureKind(in.Kind)
+	if resolved == "" {
+		return nil, fmt.Errorf("%w: %q", ErrInvalidStructureKind, in.Kind)
+	}
+	if !datasetStructureSupported() {
+		return nil, errDatasetStructureUnsupported()
+	}
+	resp := &DatasetStructureGraphResponse{Kind: resolved, Templates: []DocumentStructureGraphTemplate{}}
+
+	// Discover distinct template ids whose stamped template kind resolves to the
+	// requested kind, scanning dataset-scope entity rows only. scope_kwd="dataset"
+	// is required here (unlike the legacy doc_graph fallback) because dataset rows
+	// are the only ones carrying compilation_template_kind_kwd we can trust for the
+	// dataset-scope kind match.
+	templateIDs := map[string]struct{}{}
+	// "id" must be projected: graphRowSearch keys its result map by the row id,
+	// and Infinity only returns fields listed in SelectFields (it does not
+	// synthesize id), so omitting it silently drops every row (review Major).
+	// The resolved kind is pushed into the filter so the engine applies the
+	// predicate instead of scanning all entity rows and discarding them in Go.
+	metaFields := []string{"id", "compilation_template_kind_kwd", "compilation_template_ids"}
+	for offset := 0; ; offset += 1000 {
+		rows, total, err := graphRowSearch(ctx, in.TenantID, in.DatasetID, metaFields,
+			map[string]interface{}{
+				"knowledge_graph_kwd":           []string{"entity"},
+				"scope_kwd":                     []string{"dataset"},
+				"compilation_template_kind_kwd": []string{resolved},
+			}, nil, offset, 1000, nil)
+		if err != nil {
+			return nil, err
+		}
+		for _, row := range rows {
+			tkind := firstStringValue(row["compilation_template_kind_kwd"])
+			if tkind == "" || resolveDatasetStructureKind(tkind) != resolved {
+				continue
+			}
+			tid := rowTemplateID(row)
+			if tid != "" {
+				templateIDs[tid] = struct{}{}
+			}
+		}
+		if int64(offset+1000) >= total || len(rows) == 0 {
+			break
+		}
+	}
+
+	// Read each template's dataset entity/relation rows.
+	for tid := range templateIDs {
+		scope := map[string]interface{}{
+			"scope_kwd":                     []string{"dataset"},
+			"compilation_template_ids":      []string{tid},
+			"compilation_template_kind_kwd": []string{resolved},
+		}
+		entities, relations, err := s.buildBucket(ctx, in.TenantID, in.DatasetID, scope, nil)
+		if err != nil {
+			return nil, err
+		}
+		if len(entities) == 0 && len(relations) == 0 {
+			continue
+		}
+		resp.Templates = append(resp.Templates, DocumentStructureGraphTemplate{
+			TemplateID:   tid,
+			TemplateName: tid,
+			Kind:         resolved,
+			Entities:     entities,
+			Relations:    relations,
+		})
+	}
+	return resp, nil
+}
+
+// DeleteDatasetStructure handles DELETE /datasets/:id/artifacts/structure?kind=&wipe=.
+// It validates kind like GET. wipe=false cancels the kind's task (via the task-id
+// field) without deleting rows; wipe=true deletes the kind's kg_build_meta marker
+// + dataset entity/relation rows (document-scope rows are never touched).
+func (s *DatasetArtifactService) DeleteDatasetStructure(ctx context.Context, in DatasetStructureGraphInput) (int, error) {
+	resolved := resolveDatasetStructureKind(in.Kind)
+	if resolved == "" {
+		return 0, fmt.Errorf("%w: %q", ErrInvalidStructureKind, in.Kind)
+	}
+	if !in.Wipe {
+		// Cancel the task without deleting rows. Task cancellation is task-id
+		// granular (mirrors Python delete_index REDIS set "{task_id}-cancel"); the
+		// actual row cleanup happens on the next rebuild. Rows are preserved.
+		return s.cancelDatasetStructureTask(ctx, in.TenantID, in.DatasetID, resolved)
+	}
+	if !datasetStructureSupported() {
+		return 0, errDatasetStructureUnsupported()
+	}
+	docEngine := engine.Get()
+	if docEngine == nil {
+		return 0, fmt.Errorf("document engine is not initialized")
+	}
+	indexName := fmt.Sprintf("ragflow_%s", in.TenantID)
+	cond := map[string]interface{}{
+		"kb_id":                         in.DatasetID,
+		"scope_kwd":                     "dataset",
+		"compilation_template_kind_kwd": resolved,
+		"knowledge_graph_kwd":           []string{"entity", "relation", "kg_build_meta"},
+	}
+	n, err := docEngine.DeleteChunks(ctx, cond, indexName, in.DatasetID)
+	if err != nil {
+		return 0, err
+	}
+	return int(n), nil
+}
+
+// cancelDatasetStructureTask cancels the running dataset-structure task for a
+// resolved kind by clearing both its per-index task-id and finish-at fields.
+// This mirrors Python delete_index (dataset_api_service.py), which clears
+// {task_id_field: "", task_finish_at_field: None} so the task state is fully
+// reset (a stale finish-at would otherwise leave the kind looking "done" after
+// cancel). The row cleanup itself is driven by the next rebuild; Go executes the
+// merge synchronously inside the ingestor (no independent task/marker), so there
+// is no Redis "{task_id}-cancel" marker to publish here.
+func (s *DatasetArtifactService) cancelDatasetStructureTask(ctx context.Context, tenantID, datasetID, resolvedKind string) (int, error) {
+	field := datasetStructureTaskIDField(resolvedKind)
+	if field == "" {
+		return 0, nil
+	}
+	updates := map[string]interface{}{
+		field: "",
+		// gorm.Updates ignores nil values, so use an explicit NULL expression to
+		// actually clear the finish-at timestamp (mirrors Python None).
+		datasetStructureTaskFinishAtField(field): gorm.Expr("NULL"),
+	}
+	if err := dao.NewKnowledgebaseDAO().UpdateByID(ctx, dao.DB, datasetID, updates); err != nil {
+		return 0, err
+	}
+	return 0, nil
+}
+
+// datasetStructureTaskFinishAtField maps a task-id field to its sibling finish-at
+// field, mirroring Python f"{task_id_field.replace('_task_id', '_task_finish_at')}".
+func datasetStructureTaskFinishAtField(taskIDField string) string {
+	return strings.Replace(taskIDField, "_task_id", "_task_finish_at", 1)
+}
+
+// datasetStructureTaskIDField maps a resolved dataset-structure kind to its kb
+// task-id field name. It mirrors Python _INDEX_TYPE_TO_TASK_ID_FIELD: each
+// dataset-merge kind carries its own "<index_type>_task_id" field (structure_graph,
+// structure_mindmap, timeline, session_graph, session_essence), NOT the legacy
+// doc-level graphrag_task_id/mindmap_task_id. Empty means "no task-id field".
+func datasetStructureTaskIDField(resolvedKind string) string {
+	switch resolvedKind {
+	case "knowledge_graph":
+		// "graph" is already normalized to "knowledge_graph" by
+		// resolveDatasetStructureKind, so no separate "graph" case is needed.
+		return "structure_graph_task_id"
+	case "mindmap", "mind_map":
+		return "structure_mindmap_task_id"
+	case "timeline":
+		return "timeline_task_id"
+	case "session_graph":
+		return "session_graph_task_id"
+	case "session_essence":
+		return "session_essence_task_id"
+	}
+	return ""
+}
+
 // resolveGraphBucket mirrors Python _resolve_bucket.
 func resolveGraphBucket(row map[string]interface{}, templateMeta map[string]map[string]interface{}, documentID string) (map[string]interface{}, map[string]interface{}) {
 	compileKwd := firstStringValue(row["compile_kwd"])
@@ -866,7 +1118,7 @@ func rowTemplateID(row map[string]interface{}) string {
 }
 
 func (s *DatasetArtifactService) appendRaptorBlob(ctx context.Context, tenantID, datasetID, documentID string, grouped map[string]DocumentStructureGraphTemplate) {
-	rows, _, err := graphRowSearch(ctx, tenantID, datasetID, []string{"content_with_weight", "compile_kwd"},
+	rows, _, err := graphRowSearch(ctx, tenantID, datasetID, []string{"id", "content_with_weight", "compile_kwd"},
 		map[string]interface{}{"doc_id": []string{documentID}, "compile_kwd": []string{"raptor_graph"}}, nil, 0, 16, nil)
 	if err != nil {
 		return
diff --git a/internal/service/ingestion_task_service_test.go b/internal/service/ingestion_task_service_test.go
index 53c8d1f217..e8a05d4ec6 100644
--- a/internal/service/ingestion_task_service_test.go
+++ b/internal/service/ingestion_task_service_test.go
@@ -875,6 +875,45 @@ func TestIngestionTaskServiceMarkStoppedIdempotentOnAlreadyStopped(t *testing.T)
 	}
 }
 
+// TestIngestionTaskServiceRequestStopNeverReopensTerminalTask locks the invariant
+// that a terminal task (COMPLETED/STOPPED/FAILED) can never be moved back to
+// STOPPING. A terminal task whose message was already acked must not regress to
+// the in-flight STOPPING state (which has no settled worker and would be stuck
+// forever). RequestStop is a no-op for terminal states.
+func TestIngestionTaskServiceRequestStopNeverReopensTerminalTask(t *testing.T) {
+	for _, status := range []string{common.COMPLETED, common.STOPPED, common.FAILED} {
+		t.Run(status, func(t *testing.T) {
+			db := setupServiceTestDB(t)
+			pushServiceDB(t, db)
+			insertTestIngestionTaskWithStatus(t, "task-1", "user-1", "doc-1", "kb-1", status)
+			ctx := t.Context()
+
+			svc := NewIngestionTaskService()
+			task, err := svc.RequestStop(ctx, "task-1")
+			if err != nil {
+				t.Fatalf("RequestStop on %s task should be a no-op, got: %v", status, err)
+			}
+			if task.Status != status {
+				t.Fatalf("RequestStop moved %s task to %q, must stay %s", status, task.Status, status)
+			}
+		})
+	}
+}
+
+// TestValidateTransitionRejectsTerminalToStopping locks the state-machine
+// invariant directly: STOPPING is only reachable from RUNNING, never from a
+// terminal state (COMPLETED/STOPPED/FAILED) or from STOPPING itself.
+func TestValidateTransitionRejectsTerminalToStopping(t *testing.T) {
+	for _, from := range []string{common.COMPLETED, common.STOPPED, common.FAILED, common.STOPPING, common.CREATED} {
+		if err := validateTransition(from, common.STOPPING); err == nil {
+			t.Errorf("validateTransition(%s -> STOPPING) = nil, want error", from)
+		}
+	}
+	if err := validateTransition(common.RUNNING, common.STOPPING); err != nil {
+		t.Errorf("validateTransition(RUNNING -> STOPPING) = %v, want nil", err)
+	}
+}
+
 func TestIngestionTaskServiceMarkFailedIdempotentOnAlreadyTerminal(t *testing.T) {
 	db := setupServiceTestDB(t)
 	pushServiceDB(t, db)
diff --git a/internal/service/nav_embedder.go b/internal/service/nav_embedder.go
index 6598695291..891e79bff0 100644
--- a/internal/service/nav_embedder.go
+++ b/internal/service/nav_embedder.go
@@ -20,6 +20,8 @@ import (
 	"context"
 	"fmt"
 	"strings"
+
+	"ragflow/internal/entity"
 )
 
 // NavEmbedder is the production implementation of nlp.NavEmbedder. It resolves
@@ -45,7 +47,17 @@ func (e *NavEmbedder) Encode(ctx context.Context, tenantID string, texts []strin
 	}
 	name := e.embdModelName
 	if name == "" {
-		name = tenantID // composite name falls back to tenant default resolution
+		// Resolve the tenant's default embedding model composite reference
+		// ("<model>@<instance>@<provider>") — NOT the tenant id. Passing the
+		// tenant id as the model ref makes ResolveModelConfig parse it as a
+		// "model@provider" key, which fails with "provider name missing in model
+		// name: <tenant_id>". Mirrors knowledge_compiler_wiring.go's chat-model
+		// default resolution.
+		ref, err := e.modelSvc.GetTenantDefaultModelRef(ctx, tenantID, entity.ModelTypeEmbedding)
+		if err != nil {
+			return nil, fmt.Errorf("datasetnav: resolve embedding model for tenant %s: %w", tenantID, err)
+		}
+		name = ref
 	}
 	model, err := e.modelSvc.GetEmbeddingModel(ctx, tenantID, name)
 	if err != nil {
diff --git a/web/src/components/structure-graph/adapters.ts b/web/src/components/structure-graph/adapters.ts
index 0d19a2a75a..e64c8e6029 100644
--- a/web/src/components/structure-graph/adapters.ts
+++ b/web/src/components/structure-graph/adapters.ts
@@ -53,7 +53,7 @@ function buildTreeDataItems(
   relationTypes: string[],
   showEntityType = false,
 ): TreeDataItem[] {
-  const normalized = entities
+  const normalized = (entities ?? [])
     .map(normalizeEntity)
     .filter((entity) => entity.id);
   const map = new Map<string, TreeDataItem>(
@@ -69,7 +69,7 @@ function buildTreeDataItems(
   );
   const childIds = new Set<string>();
 
-  for (const relation of relations) {
+  for (const relation of relations ?? []) {
     if (!relationTypes.includes(relation.type ?? '')) continue;
     // Self-referencing relation (same entity as its own child) creates
     // an infinite recursion in the tree renderer.  This is a backend
@@ -99,7 +99,7 @@ function buildUniqueTreeDataItems(
 ): TreeDataItem[] {
   const normalized = [
     ...new Map(
-      entities
+      (entities ?? [])
         .map(normalizeEntity)
         .filter((entity) => entity.id)
         .map((entity) => [entity.id, entity]),
@@ -119,7 +119,7 @@ function buildUniqueTreeDataItems(
   const childIds = new Set<string>();
   const parentMap = new Map<string, string>();
 
-  for (const relation of relations) {
+  for (const relation of relations ?? []) {
     if (!relationTypes.includes(relation.type ?? '')) continue;
 
     const parent = map.get(relation.from);
@@ -172,7 +172,7 @@ export function adaptTreeToTreeData(
 export function adaptKnowledgeGraphToForceGraph(
   template: IStructureGraphTemplate,
 ): IArtifactGraph {
-  const entities: IArtifactGraphEntity[] = template.entities.map((entity) => {
+  const entities: IArtifactGraphEntity[] = (template.entities ?? []).map((entity) => {
     const normalized = normalizeEntity(entity);
     return {
       slug: normalized.id,
@@ -189,7 +189,7 @@ export function adaptKnowledgeGraphToForceGraph(
 
   return {
     entities,
-    relations: template.relations
+    relations: (template.relations ?? [])
       .filter(
         (relation) =>
           // Only keep relations whose source and target entities both exist in the graph.
@@ -284,7 +284,7 @@ export function adaptTimelineToX6Data(template: IStructureGraphTemplate): {
     };
   });
 
-  const edges = template.relations
+  const edges = (template.relations ?? [])
     .filter(
       (relation) => entityIds.has(relation.from) && entityIds.has(relation.to),
     )