diff --git a/mateclaw-server/src/main/java/vip/mate/wiki/service/WikiKnowledgeBaseService.java b/mateclaw-server/src/main/java/vip/mate/wiki/service/WikiKnowledgeBaseService.java
index 0e4e34a2..1c8aaa6a 100644
--- a/mateclaw-server/src/main/java/vip/mate/wiki/service/WikiKnowledgeBaseService.java
+++ b/mateclaw-server/src/main/java/vip/mate/wiki/service/WikiKnowledgeBaseService.java
@@ -127,13 +127,22 @@ public class WikiKnowledgeBaseService {
      * KB just drops out). An agent with no scope rows stays workspace-wide,
      * preserving the pre-scoping behavior for every existing agent.
      * <p>
+     * An agent flagged {@code wiki_disabled=true} sees no KBs at all — the
+     * opt-out toggle wins over both workspace visibility and any leftover
+     * binding rows (the UI clears the rows when the flag is set, so the
+     * zero-row state must not fall through to "unrestricted").
+     * <p>
      * This is the single choke point for KB access: {@code wiki_list_kbs},
-     * {@link #findVisibleById}, {@link #findAllByName} and
-     * {@link #resolvePrimaryKb} all read through here, so narrowing it scopes
-     * every wiki tool at once.
+     * {@link #findVisibleById}, {@link #findAllByName},
+     * {@link #resolvePrimaryKb}, the system-prompt wiki context, and the
+     * per-turn relevant-page injection all read through here, so narrowing
+     * it scopes every wiki surface at once.
      */
     public List<WikiKnowledgeBaseEntity> listByAgentId(Long agentId) {
         AgentEntity agent = getAgentOrNull(agentId);
+        if (agent != null && Boolean.TRUE.equals(agent.getWikiDisabled())) {
+            return List.of();
+        }
         List<WikiKnowledgeBaseEntity> workspaceKbs = (agent == null || agent.getWorkspaceId() == null)
                 ? listAll()
                 : listByWorkspace(agent.getWorkspaceId());
diff --git a/mateclaw-server/src/test/java/vip/mate/wiki/service/WikiKnowledgeBaseServiceTest.java b/mateclaw-server/src/test/java/vip/mate/wiki/service/WikiKnowledgeBaseServiceTest.java
index 7be62c78..552ed3d5 100644
--- a/mateclaw-server/src/test/java/vip/mate/wiki/service/WikiKnowledgeBaseServiceTest.java
+++ b/mateclaw-server/src/test/java/vip/mate/wiki/service/WikiKnowledgeBaseServiceTest.java
@@ -15,6 +15,7 @@ import java.util.List;
 import static org.assertj.core.api.Assertions.assertThat;
 import static org.mockito.ArgumentMatchers.any;
 import static org.mockito.Mockito.mock;
+import static org.mockito.Mockito.never;
 import static org.mockito.Mockito.verify;
 import static org.mockito.Mockito.when;
 
@@ -308,4 +309,38 @@ class WikiKnowledgeBaseServiceTest {
 
         assertThat(service.resolvePrimaryKb(7L).getId()).isEqualTo(300L);
     }
+
+    // ==================== wiki_disabled opt-out (issue #551) ====================
+    //
+    // The "use no knowledge base" toggle sets mate_agent.wiki_disabled=true
+    // and clears the binding rows. Zero rows normally means "unrestricted",
+    // so the flag must short-circuit BEFORE the scope fallback — otherwise
+    // the opted-out agent sees every workspace KB again and the system
+    // prompt keeps injecting wiki content.
+
+    @Test
+    @DisplayName("wiki_disabled hides every KB: list, primary, and by-id lookups all come back empty")
+    void wikiDisabledHidesAllKbs() {
+        AgentEntity optedOut = agent(7L, 1L, 100L);
+        optedOut.setWikiDisabled(true);
+        when(agentMapper.selectById(7L)).thenReturn(optedOut);
+
+        assertThat(service.listByAgentId(7L)).isEmpty();
+        assertThat(service.resolvePrimaryKb(7L)).isNull();
+        assertThat(service.findVisibleById(7L, 100L)).isNull();
+        verify(kbMapper, never()).selectList(any());
+    }
+
+    @Test
+    @DisplayName("wiki_disabled wins over leftover binding rows")
+    void wikiDisabledWinsOverLeftoverBindings() {
+        bindScope(100L);
+        AgentEntity optedOut = agent(7L, 1L, 100L);
+        optedOut.setWikiDisabled(true);
+        when(agentMapper.selectById(7L)).thenReturn(optedOut);
+        when(kbMapper.selectList(any())).thenReturn(List.of(
+                kb(100L, null, 1L, "Bound KB")));
+
+        assertThat(service.listByAgentId(7L)).isEmpty();
+    }
 }