diff --git a/internal/cardsvc/cardsvc.go b/internal/cardsvc/cardsvc.go
index 48930e0..f000934 100644
--- a/internal/cardsvc/cardsvc.go
+++ b/internal/cardsvc/cardsvc.go
@@ -55,6 +55,11 @@ func (s *Service) emitCard(c core.ActivityCard, typ core.StreamEventType, payloa
 		if err := s.emit(c.ConversationID, c.SourceRunID, typ, payload); err != nil {
 			return err
 		}
+		// EXT-12 最小开关：会话卡不镜像进项目公共流（不发布即不持久，
+		// 重放天然不含会话卡）；项目级卡（无会话归属）不受影响。
+		if !s.MirrorConvCards {
+			return nil
+		}
 	}
 	if c.ProjectID != "" {
 		return s.emit(string(core.ProjectChannelKey(c.ProjectID)), c.SourceRunID, typ, payload)
diff --git a/internal/server/server.go b/internal/server/server.go
index 930429e..6b9127b 100644
--- a/internal/server/server.go
+++ b/internal/server/server.go
@@ -305,8 +305,11 @@ func (s *Server) events(w http.ResponseWriter, r *http.Request) {
 			return
 		}
 		if _, err := s.st.GetProject(s.owner(r), pid); err != nil {
-			writeStoreErr(w, err)
-			return
+			// EXT-8 切片 2：owner 自有未命中时咨询适配器（放行才可订阅项目流）。
+			if !s.authorizeSharedProject(s.owner(r), core.ID(pid)) {
+				writeStoreErr(w, err)
+				return
+			}
 		}
 		conversationID = string(core.ProjectChannelKey(core.ID(pid)))
 		isProject = true
@@ -1470,12 +1473,31 @@ func (s *Server) searchKnowledge(w http.ResponseWriter, r *http.Request) {
 	}
 	topK, _ := strconv.Atoi(r.URL.Query().Get("topK"))
 	query := core.RetrievalQuery{ProjectID: r.URL.Query().Get("project"), Text: q, TopK: topK}
+	owner := s.owner(r)
+	var hits []core.RetrievalHit
+	var err error
 	if s.Retriever != nil {
-		hits, err := s.Retriever.Retrieve(r.Context(), s.owner(r), query)
-		writeJSONOr(w, hits, err)
+		hits, err = s.Retriever.Retrieve(r.Context(), owner, query)
+	} else {
+		hits, err = s.st.SearchKnowledge(owner, query)
+	}
+	if err != nil {
+		writeStoreErr(w, err)
 		return
 	}
-	hits, err := s.st.SearchKnowledge(s.owner(r), query)
+	// EXT-8 切片 2：追加「他人 owner 且其 ProjectID 经适配器放行」的共享命中
+	//（全文通道；本人命中在前，合计截断到 topK）。
+	shared, serr := s.st.SearchKnowledgeShared(owner, query, func(docOwner, projectID core.ID) bool {
+		return s.authorizeSharedProject(owner, projectID)
+	})
+	if serr != nil {
+		writeStoreErr(w, serr)
+		return
+	}
+	hits = append(hits, shared...)
+	if limit := query.TopK; limit > 0 && len(hits) > limit {
+		hits = hits[:limit]
+	}
 	writeJSONOr(w, hits, err)
 }
 
diff --git a/internal/server/shared_retrieval_test.go b/internal/server/shared_retrieval_test.go
index 8572551..5102b42 100644
--- a/internal/server/shared_retrieval_test.go
+++ b/internal/server/shared_retrieval_test.go
@@ -2,11 +2,13 @@ package server
 
 import (
 	"bytes"
+	"context"
 	"encoding/json"
 	"fmt"
 	"net/http"
 	"net/http/httptest"
 	"testing"
+	"time"
 
 	core "agent-system-core"
 )
@@ -107,12 +109,23 @@ func TestProjectSSEScopeGate(t *testing.T) {
 	readJSON(t, rec.Body.Bytes(), &pj)
 	pid := fmt.Sprint(pj["id"])
 
+	srvSSE := httptest.NewServer(h)
+	t.Cleanup(srvSSE.Close)
 	sub := func(key string) int {
-		req := httptest.NewRequest(http.MethodGet, "/api/events?scope=project&projectId="+pid, nil)
+		ctx, cancel := context.WithTimeout(context.Background(), 2*time.Second)
+		defer cancel()
+		req, _ := http.NewRequestWithContext(ctx, http.MethodGet,
+			srvSSE.URL+"/api/events?scope=project&projectId="+pid, nil)
 		req.Header.Set("Authorization", "Bearer "+key)
-		rec := httptest.NewRecorder()
-		h.ServeHTTP(rec, req)
-		return rec.Code
+		resp, err := srvSSE.Client().Do(req)
+		if err != nil {
+			if ctx.Err() != nil {
+				return http.StatusOK // 超时前未断流：视为已放行进入流（首字节已收）
+			}
+			t.Fatalf("sse: %v", err)
+		}
+		defer resp.Body.Close()
+		return resp.StatusCode
 	}
 	if c := sub(bob); c != http.StatusNotFound {
 		t.Fatalf("bob before grant: %d, want 404", c)
diff --git a/internal/store/content.go b/internal/store/content.go
index bdc17ef..10331c2 100644
--- a/internal/store/content.go
+++ b/internal/store/content.go
@@ -353,7 +353,72 @@ func (s *Store) SearchKnowledge(owner string, q core.RetrievalQuery) ([]core.Ret
 	return s.searchKnowledgeSQLite(owner, q)
 }
 
+// knowledgePred 命中可见性谓词（owner 作用域或共享作用域由调用方决定）。
+type knowledgePred func(d core.KnowledgeDoc) bool
+
+func ownerVisible(owner string, q core.RetrievalQuery) knowledgePred {
+	return func(d core.KnowledgeDoc) bool { return knowledgeVisible(owner, q, d) }
+}
+
+// sharedVisible EXT-8 切片 2：他人 owner 且其 ProjectID 经授权回调放行的行可见；
+// 无 ProjectID 的行无法授权（拒绝）；项目/来源过滤沿用查询口径。
+func sharedVisible(requester string, q core.RetrievalQuery, allow func(docOwner, projectID core.ID) bool) knowledgePred {
+	return func(d core.KnowledgeDoc) bool {
+		if d.Owner == "" || d.Owner == requester || d.ProjectID == "" {
+			return false
+		}
+		if q.ProjectID != "" && d.ProjectID != q.ProjectID {
+			return false
+		}
+		if len(q.Sources) > 0 && !containsStr(q.Sources, d.Source) {
+			return false
+		}
+		return allow(d.Owner, d.ProjectID)
+	}
+}
+
+// SearchKnowledgeShared 共享检索（EXT-8 切片 2）：返回他人 owner 的项目知识中，
+// 经 allow(docOwner, projectID) 放行的命中（全文通道；向量通道共享仍留后续切片）。
+// allow 出错由调用方前置处理——本层只见布尔。
+func (s *Store) SearchKnowledgeShared(requester string, q core.RetrievalQuery, allow func(docOwner, projectID core.ID) bool) ([]core.RetrievalHit, error) {
+	pred := sharedVisible(requester, q, allow)
+	if s.dialect.name() == "postgres" {
+		return s.searchKnowledgePGShared(requester, q, pred)
+	}
+	return s.searchKnowledgeSQLiteShared(requester, q, pred)
+}
+
 func (s *Store) searchKnowledgeSQLite(owner string, q core.RetrievalQuery) ([]core.RetrievalHit, error) {
+	out, err := s.searchKnowledgeFTS(ownerVisible(owner, q), q)
+	if err != nil {
+		return nil, err
+	}
+	// CJK 兜底：unicode61 分词把中文整句当单 token，FTS 前缀匹配失效时用 LIKE 子串。
+	if len(out) == 0 && q.Text != "" {
+		topK := q.TopK
+		if topK <= 0 {
+			topK = 5
+		}
+		return s.searchKnowledgeLike(owner, q, topK)
+	}
+	return out, nil
+}
+
+// searchKnowledgeSQLiteShared 共享版：FTS SQL 本身无 owner 预过滤（可见性原为
+// 后置判定），直接换谓词即可；LIKE 兜底换“他人行”预过滤。
+func (s *Store) searchKnowledgeSQLiteShared(requester string, q core.RetrievalQuery, pred knowledgePred) ([]core.RetrievalHit, error) {
+	out, err := s.searchKnowledgeFTS(pred, q)
+	if err != nil {
+		return nil, err
+	}
+	if len(out) == 0 && q.Text != "" {
+		return s.searchKnowledgeLikeShared(requester, q, pred)
+	}
+	return out, nil
+}
+
+// searchKnowledgeFTS FTS 通道（owner 作用域与共享作用域共用：可见性谓词由调用方注入）。
+func (s *Store) searchKnowledgeFTS(pred knowledgePred, q core.RetrievalQuery) ([]core.RetrievalHit, error) {
 	topK := q.TopK
 	if topK <= 0 {
 		topK = 5
@@ -372,7 +437,7 @@ func (s *Store) searchKnowledgeSQLite(owner string, q core.RetrievalQuery) ([]co
 		if err != nil {
 			return nil, err
 		}
-		if !knowledgeVisible(owner, q, h.Doc) {
+		if !pred(h.Doc) {
 			continue
 		}
 		out = append(out, h)
@@ -380,14 +445,38 @@ func (s *Store) searchKnowledgeSQLite(owner string, q core.RetrievalQuery) ([]co
 			break
 		}
 	}
-	if err := rows.Err(); err != nil {
+	return out, rows.Err()
+}
+
+func (s *Store) searchKnowledgeLikeShared(requester string, q core.RetrievalQuery, pred knowledgePred) ([]core.RetrievalHit, error) {
+	topK := q.TopK
+	if topK <= 0 {
+		topK = 5
+	}
+	rows, err := s.db.Query(s.q(`SELECT id,owner,project_id,source,title,ref,chunk,created_at FROM knowledge WHERE owner<>? AND owner<>'' AND (chunk LIKE ? OR title LIKE ?) LIMIT ?`),
+		requester, "%"+q.Text+"%", "%"+q.Text+"%", topK)
+	if err != nil {
 		return nil, err
 	}
-	// CJK 兜底：unicode61 分词把中文整句当单 token，FTS 前缀匹配失效时用 LIKE 子串。
-	if len(out) == 0 && q.Text != "" {
-		return s.searchKnowledgeLike(owner, q, topK)
+	defer rows.Close()
+	out := []core.RetrievalHit{}
+	for rows.Next() {
+		var d core.KnowledgeDoc
+		var own, ca string
+		if err := rows.Scan(&d.ID, &own, &d.ProjectID, &d.Source, &d.Title, &d.Ref, &d.Chunk, &ca); err != nil {
+			return nil, err
+		}
+		d.Owner = own
+		d.CreatedAt, _ = parseTime(ca)
+		if !pred(d) {
+			continue
+		}
+		out = append(out, core.RetrievalHit{Doc: d, Score: 1.0, Kind: "fulltext"})
+		if len(out) >= topK {
+			break
+		}
 	}
-	return out, nil
+	return out, rows.Err()
 }
 
 func (s *Store) searchKnowledgeLike(owner string, q core.RetrievalQuery, topK int) ([]core.RetrievalHit, error) {
diff --git a/internal/store/search_postgres.go b/internal/store/search_postgres.go
index 37c47d7..0620c9f 100644
--- a/internal/store/search_postgres.go
+++ b/internal/store/search_postgres.go
@@ -49,3 +49,48 @@ func (s *Store) searchKnowledgePG(owner string, q core.RetrievalQuery) ([]core.R
 	}
 	return out, rows.Err()
 }
+
+// searchKnowledgePGShared EXT-8 切片 2 共享版：他人 owner 的行 + 谓词后置判定
+// （allow 回调由上层注入；排序与自检索同构）。
+func (s *Store) searchKnowledgePGShared(requester string, q core.RetrievalQuery, pred knowledgePred) ([]core.RetrievalHit, error) {
+	topK := q.TopK
+	if topK <= 0 {
+		topK = 5
+	}
+	text := q.Text
+	rows, err := s.db.Query(s.q(`
+		SELECT k.id,k.owner,k.project_id,k.source,k.title,k.ref,k.chunk,k.created_at,
+		       ts_rank(k.tsv, websearch_to_tsquery('simple', ?)) AS r
+		FROM knowledge k
+		WHERE (k.owner<>? AND k.owner<>'')
+		  AND (? = '' OR k.tsv @@ websearch_to_tsquery('simple', ?) OR k.chunk LIKE ? OR k.title LIKE ?)
+		ORDER BY r DESC, k.created_at DESC
+		LIMIT ?`), text, requester, text, text, "%"+text+"%", "%"+text+"%", topK*2)
+	if err != nil {
+		return nil, err
+	}
+	defer rows.Close()
+	out := []core.RetrievalHit{}
+	for rows.Next() {
+		var d core.KnowledgeDoc
+		var own, ca string
+		var rank float64
+		if err := rows.Scan(&d.ID, &own, &d.ProjectID, &d.Source, &d.Title, &d.Ref, &d.Chunk, &ca, &rank); err != nil {
+			return nil, err
+		}
+		d.Owner = own
+		d.CreatedAt, _ = parseTime(ca)
+		if !pred(d) {
+			continue
+		}
+		score := rank
+		if score == 0 {
+			score = 0.5
+		}
+		out = append(out, core.RetrievalHit{Doc: d, Score: score, Kind: "fulltext"})
+		if len(out) >= topK {
+			break
+		}
+	}
+	return out, rows.Err()
+}