diff --git a/muse-cloud/muse-module-knowledge/muse-module-knowledge-server/src/main/java/cn/iocoder/muse/module/knowledge/application/muse/facade/HttpRagFlowKnowledgeRuntimeClient.java b/muse-cloud/muse-module-knowledge/muse-module-knowledge-server/src/main/java/cn/iocoder/muse/module/knowledge/application/muse/facade/HttpRagFlowKnowledgeRuntimeClient.java
index f0007610..d4c966f2 100644
--- a/muse-cloud/muse-module-knowledge/muse-module-knowledge-server/src/main/java/cn/iocoder/muse/module/knowledge/application/muse/facade/HttpRagFlowKnowledgeRuntimeClient.java
+++ b/muse-cloud/muse-module-knowledge/muse-module-knowledge-server/src/main/java/cn/iocoder/muse/module/knowledge/application/muse/facade/HttpRagFlowKnowledgeRuntimeClient.java
@@ -144,7 +144,11 @@ public class HttpRagFlowKnowledgeRuntimeClient implements RagFlowKnowledgeRuntim
     public RuntimeResult retrieveChunks(RetrieveChunksCommand command) {
         Map<String, Object> body = new LinkedHashMap<>();
         body.put("dataset_ids", command.ragflowDatasetIds());
-        body.put("document_ids", command.ragflowDocumentIds());
+        // RAGFlow 要求 document_ids 为 list;为 null(不限定具体文档、按授权 dataset 全量检索)时不放入 body,
+        // 否则 RAGFlow 拒绝 code 102 "`documents` should be a list" → 检索 fail-closed,P-A 上下文检索永不命中。
+        if (command.ragflowDocumentIds() != null) {
+            body.put("document_ids", command.ragflowDocumentIds());
+        }
         body.put("question", command.question());
         body.put("top_k", command.topK());
         body.put("similarity_threshold", command.threshold());
diff --git a/muse-cloud/muse-module-knowledge/muse-module-knowledge-server/src/test/java/cn/iocoder/muse/module/knowledge/application/muse/facade/RagFlowKnowledgeRuntimeClientTest.java b/muse-cloud/muse-module-knowledge/muse-module-knowledge-server/src/test/java/cn/iocoder/muse/module/knowledge/application/muse/facade/RagFlowKnowledgeRuntimeClientTest.java
index f40cd2b3..3284a77e 100644
--- a/muse-cloud/muse-module-knowledge/muse-module-knowledge-server/src/test/java/cn/iocoder/muse/module/knowledge/application/muse/facade/RagFlowKnowledgeRuntimeClientTest.java
+++ b/muse-cloud/muse-module-knowledge/muse-module-knowledge-server/src/test/java/cn/iocoder/muse/module/knowledge/application/muse/facade/RagFlowKnowledgeRuntimeClientTest.java
@@ -347,6 +347,24 @@ class RagFlowKnowledgeRuntimeClientTest {
         assertFalse(result.redactedSummary().contains("private prompt"));
     }
 
+    @Test
+    void retrieveChunksShouldOmitDocumentIdsFromBodyWhenNull() {
+        // 回归:document_ids 为 null(P-A 按授权 dataset 全量检索、不限定具体文档)时不得放入 body;
+        // RAGFlow 要求其为 list,传 null 会被拒 code 102 "`documents` should be a list" 致检索 fail-closed → P-A 永不命中。
+        CapturingHttpRagFlowKnowledgeRuntimeClient client = new CapturingHttpRagFlowKnowledgeRuntimeClient(
+                "https://ragflow.example", "configured-api-key",
+                "{\"code\":0,\"data\":{\"chunks\":[{\"content\":\"c\",\"score\":0.9}]}}");
+
+        RagFlowKnowledgeRuntimeClient.RuntimeResult result = client.retrieveChunks(
+                new RagFlowKnowledgeRuntimeClient.RetrieveChunksCommand(100L, 2001L, 4001L,
+                        List.of("dataset-1"), null, "q", 5, 0.2, null, "corr-null-doc", "hash-null-doc", 1));
+
+        assertEquals(RagFlowKnowledgeRuntimeClient.Status.SUCCEEDED, result.status());
+        String requestBody = new String(client.requests.get(0).body(), StandardCharsets.UTF_8);
+        assertFalse(requestBody.contains("document_ids"), "document_ids 为 null 时不应出现在请求 body");
+        assertTrue(requestBody.contains("dataset_ids"));
+    }
+
     @Test
     void listChunksShouldSucceedWithoutTopLevelId() {
         HttpRagFlowKnowledgeRuntimeClient client = new StubHttpRagFlowKnowledgeRuntimeClient(