diff --git a/mateclaw-server/src/main/java/vip/mate/tool/builtin/SessionListTool.java b/mateclaw-server/src/main/java/vip/mate/tool/builtin/SessionListTool.java
index 6ceba1db..83e899f2 100644
--- a/mateclaw-server/src/main/java/vip/mate/tool/builtin/SessionListTool.java
+++ b/mateclaw-server/src/main/java/vip/mate/tool/builtin/SessionListTool.java
@@ -1,5 +1,6 @@
 package vip.mate.tool.builtin;
 
+import com.baomidou.mybatisplus.core.conditions.query.LambdaQueryWrapper;
 import lombok.RequiredArgsConstructor;
 import lombok.extern.slf4j.Slf4j;
 import org.springframework.ai.tool.annotation.Tool;
@@ -8,25 +9,30 @@ import org.springframework.ai.chat.model.ToolContext;
 import org.springframework.stereotype.Component;
 import vip.mate.agent.delegation.SubagentRegistry;
 import vip.mate.agent.delegation.SubagentRegistry.SubagentRecord;
+import vip.mate.workspace.conversation.model.ConversationEntity;
+import vip.mate.workspace.conversation.repository.ConversationMapper;
 
+import java.util.LinkedHashMap;
 import java.util.List;
+import java.util.Map;
 
 /**
- * Read-only session listing tool: enumerates the live sub-agents spawned from
- * the current conversation's delegation tree.
+ * Read-only session listing tool: enumerates the sub-agents the current
+ * conversation has delegated to — both the ones still running and the ones that
+ * have finished and can be followed up on.
  *
  * <p>Completes the spawn / send / list triad alongside {@link DelegateAgentTool}
- * (spawn). Where {@code delegateParallel} fans children out and blocks for their
- * combined result, this lets the parent agent inspect the tree mid-reasoning —
- * which children are still running, what phase / tool each is on, how many tool
- * calls each has made — so it can decide whether to wait, follow up, or move on
- * instead of re-dispatching roles it already spawned.
+ * (spawn) and {@link SessionSendTool} (send). It is the discovery surface for
+ * send: each row carries the {@code session_id} (the child's persisted
+ * conversation id) so the parent can pick a finished child and continue it,
+ * which the live in-memory registry alone cannot show (it drops a child the
+ * moment it completes).
  *
- * <p>Resolves the human-facing root conversation the same way the delegation
- * relay does ({@link DelegationContext#rootConversationId()} when running inside
- * a delegated layer, otherwise the current {@link ToolExecutionContext}
- * conversation), then reads the in-memory {@link SubagentRegistry}. It never
- * mutates state, so it is safe for children to call as well.
+ * <p>Source of truth is the persisted direct children of the caller's
+ * conversation (so finished sessions stay discoverable), overlaid with live
+ * status from {@link SubagentRegistry} for any child still running. Resolves the
+ * caller conversation the same way the delegation relay does. Read-only, so it
+ * is safe for children to call.
  *
  * @author MateClaw Team
  */
@@ -35,46 +41,68 @@ import java.util.List;
 @RequiredArgsConstructor
 public class SessionListTool {
 
+    /** Cap on rows so a conversation with a long delegation history stays readable. */
+    private static final int MAX_ROWS = 30;
+
     private final SubagentRegistry subagentRegistry;
+    private final ConversationMapper conversationMapper;
 
     @Tool(description = """
-            List the live sub-agents spawned from the current conversation, including each one's
-            id, target agent, tree depth, status (running/completed/interrupted/stale/timeout),
-            current phase, tool-call count, elapsed time, and goal. Read-only: use it to check on
-            children you delegated before deciding to wait, follow up, or proceed — do NOT re-spawn
-            a role that is already listed as running.""")
+            List the sub-agents this conversation has delegated to — both running and finished —
+            with each one's session_id, target agent, status, and goal/title. Use it to discover a
+            session_id to follow up on via send_to_subagent, or to check whether a child you
+            delegated is still running before deciding to wait or proceed. Read-only.""")
     public String listSubagents(@Nullable ToolContext ctx) {
-        String rootConversationId = resolveRootConversationId();
-        if (rootConversationId == null || rootConversationId.isBlank()) {
-            return "No active sub-agents (no conversation context).";
+        String callerConversationId = resolveCallerConversationId();
+        if (callerConversationId == null || callerConversationId.isBlank()) {
+            return "No sub-agent sessions (no conversation context).";
         }
 
-        List<SubagentRecord> records = subagentRegistry.snapshotTree(rootConversationId);
-        if (records.isEmpty()) {
-            return "No active sub-agents for this conversation.";
+        // Persisted direct children — the sendable sessions, including finished ones.
+        List<ConversationEntity> children = conversationMapper.selectList(
+                new LambdaQueryWrapper<ConversationEntity>()
+                        .eq(ConversationEntity::getParentConversationId, callerConversationId)
+                        .eq(ConversationEntity::getDeleted, 0)
+                        .orderByDesc(ConversationEntity::getLastActiveTime)
+                        .last("LIMIT " + MAX_ROWS));
+
+        // Live status overlay, keyed by the child conversation id.
+        Map<String, SubagentRecord> liveByConv = new LinkedHashMap<>();
+        for (SubagentRecord r : subagentRegistry.snapshot(callerConversationId)) {
+            if (r.childConversationId() != null) {
+                liveByConv.put(r.childConversationId(), r);
+            }
+        }
+
+        if (children.isEmpty() && liveByConv.isEmpty()) {
+            return "No sub-agent sessions for this conversation.";
         }
 
         long now = System.currentTimeMillis();
         StringBuilder sb = new StringBuilder();
-        sb.append("Active sub-agents (").append(records.size()).append("):\n");
-        // Stable, human-readable order: shallow layers first, then by spawn time
-        // so a parent reads its direct children before their descendants.
-        records.stream()
-                .sorted((a, b) -> {
-                    int byDepth = Integer.compare(a.depth(), b.depth());
-                    return byDepth != 0 ? byDepth : Long.compare(a.startedAt(), b.startedAt());
-                })
-                .forEach(r -> sb.append(formatRecord(r, now)).append('\n'));
-        return sb.toString().stripTrailing();
+        sb.append("Sub-agent sessions for this conversation (").append(
+                Math.max(children.size(), liveByConv.size())).append("):\n");
+
+        for (ConversationEntity child : children) {
+            String convId = child.getConversationId();
+            SubagentRecord live = liveByConv.remove(convId);
+            sb.append(live != null ? formatLive(convId, live, now) : formatPersisted(child)).append('\n');
+        }
+        // Any live record whose persisted row wasn't returned (e.g. just spawned,
+        // outside the LIMIT window) still gets listed so nothing in flight hides.
+        for (Map.Entry<String, SubagentRecord> e : liveByConv.entrySet()) {
+            sb.append(formatLive(e.getKey(), e.getValue(), now)).append('\n');
+        }
+
+        sb.append("Follow up with send_to_subagent(session_id, message).");
+        return sb.toString();
     }
 
     /**
-     * Root of the delegation tree to list: the relay-carried root when this call
-     * happens inside a delegated layer, falling back to the current conversation
-     * (the top-level agent's own conversation, which is the tree root for the
-     * children it spawned).
+     * Caller conversation to scope the listing to: the relay-carried root when
+     * this runs inside a delegated layer, otherwise the current conversation.
      */
-    private String resolveRootConversationId() {
+    private String resolveCallerConversationId() {
         String root = DelegationContext.rootConversationId();
         if (root != null && !root.isBlank()) {
             return root;
@@ -86,18 +114,31 @@ public class SessionListTool {
         }
     }
 
-    private String formatRecord(SubagentRecord r, long now) {
+    private String formatLive(String convId, SubagentRecord r, long now) {
         long elapsedSec = Math.max(0, (now - r.startedAt()) / 1000);
-        String goal = r.goal() == null ? "" : r.goal();
-        if (goal.length() > 80) {
-            goal = goal.substring(0, 80) + "…";
+        return "- session_id=" + convId
+                + " | agent=" + r.agentId()
+                + " | " + r.status().get()
+                + " | phase=" + r.currentPhase().get()
+                + " | tools=" + r.toolCount().get()
+                + " | elapsed=" + elapsedSec + "s"
+                + " | goal=\"" + clip(r.goal(), 80) + "\"";
+    }
+
+    private String formatPersisted(ConversationEntity child) {
+        String title = child.getTitle();
+        String when = child.getLastActiveTime() != null ? child.getLastActiveTime().toString() : "";
+        return "- session_id=" + child.getConversationId()
+                + " | agent=" + child.getAgentId()
+                + " | idle"
+                + (when.isEmpty() ? "" : " | last active " + when)
+                + (title == null || title.isBlank() ? "" : " | \"" + clip(title, 80) + "\"");
+    }
+
+    private static String clip(String text, int max) {
+        if (text == null) {
+            return "";
         }
-        return "- [" + r.subagentId() + "] agent=" + r.agentId()
-                + " depth=" + r.depth()
-                + " status=" + r.status().get()
-                + " phase=" + r.currentPhase().get()
-                + " tools=" + r.toolCount().get()
-                + " elapsed=" + elapsedSec + "s"
-                + " goal=\"" + goal + "\"";
+        return text.length() <= max ? text : text.substring(0, max) + "…";
     }
 }
diff --git a/mateclaw-server/src/test/java/vip/mate/tool/builtin/SessionListToolTest.java b/mateclaw-server/src/test/java/vip/mate/tool/builtin/SessionListToolTest.java
index 2f5e1f33..a7aa80c5 100644
--- a/mateclaw-server/src/test/java/vip/mate/tool/builtin/SessionListToolTest.java
+++ b/mateclaw-server/src/test/java/vip/mate/tool/builtin/SessionListToolTest.java
@@ -1,29 +1,53 @@
 package vip.mate.tool.builtin;
 
+import com.baomidou.mybatisplus.core.metadata.TableInfoHelper;
+import org.apache.ibatis.builder.MapperBuilderAssistant;
 import org.junit.jupiter.api.AfterEach;
+import org.junit.jupiter.api.BeforeAll;
 import org.junit.jupiter.api.BeforeEach;
 import org.junit.jupiter.api.Test;
+import org.junit.jupiter.api.extension.ExtendWith;
+import org.mockito.Mock;
+import org.mockito.junit.jupiter.MockitoExtension;
 import vip.mate.agent.delegation.SubagentRegistry;
+import vip.mate.workspace.conversation.model.ConversationEntity;
+import vip.mate.workspace.conversation.repository.ConversationMapper;
 
+import java.time.LocalDateTime;
+import java.util.List;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
 import static org.junit.jupiter.api.Assertions.assertFalse;
 import static org.junit.jupiter.api.Assertions.assertTrue;
+import static org.mockito.ArgumentMatchers.any;
+import static org.mockito.Mockito.when;
 
 /**
  * Unit tests for {@link SessionListTool} — the read-only "list" leg of the
- * spawn / send / list triad.
+ * spawn / send / list triad, with DB-backed discovery of persisted child
+ * sessions overlaid by live registry status.
  *
  * @author MateClaw Team
  */
+@ExtendWith(MockitoExtension.class)
 class SessionListToolTest {
 
+    @Mock ConversationMapper conversationMapper;
+
     private SubagentRegistry registry;
     private SessionListTool tool;
 
+    @BeforeAll
+    static void initMyBatisPlusCache() {
+        TableInfoHelper.initTableInfo(
+                new MapperBuilderAssistant(new org.apache.ibatis.session.Configuration(), ""),
+                ConversationEntity.class);
+    }
+
     @BeforeEach
     void setUp() {
         registry = new SubagentRegistry();
-        tool = new SessionListTool(registry);
-        // Drain any delegation frames a prior test may have leaked on this thread.
+        tool = new SessionListTool(registry, conversationMapper);
         while (DelegationContext.currentDepth() > 0) {
             DelegationContext.exit();
         }
@@ -38,51 +62,73 @@ class SessionListToolTest {
         }
     }
 
+    private static ConversationEntity child(String conversationId, Long agentId, String title) {
+        ConversationEntity c = new ConversationEntity();
+        c.setConversationId(conversationId);
+        c.setParentConversationId("conv-root");
+        c.setAgentId(agentId);
+        c.setTitle(title);
+        c.setLastActiveTime(LocalDateTime.now());
+        return c;
+    }
+
     @Test
     void reportsNoContextWhenConversationUnknown() {
-        // No ToolExecutionContext conversation and no delegation frame.
         String out = tool.listSubagents(null);
-        assertTrue(out.contains("no conversation context"),
-                "expected a no-context message, got: " + out);
+        assertTrue(out.contains("no conversation context"), out);
     }
 
     @Test
-    void reportsEmptyTreeWhenNoSubagents() {
+    void reportsEmptyWhenNoSessions() {
         ToolExecutionContext.set("conv-root", "tester");
+        when(conversationMapper.selectList(any())).thenReturn(List.of());
         String out = tool.listSubagents(null);
-        assertTrue(out.contains("No active sub-agents for this conversation"),
-                "expected an empty-tree message, got: " + out);
+        assertTrue(out.contains("No sub-agent sessions for this conversation"), out);
     }
 
     @Test
-    void listsActiveSubagentsForCurrentConversation() {
+    void listsPersistedSessionsWithSessionIds() {
         ToolExecutionContext.set("conv-root", "tester");
-        registry.register("conv-root", "child-1", 11L, "research the topic", null);
+        when(conversationMapper.selectList(any())).thenReturn(List.of(
+                child("child-1", 11L, "research the topic"),
+                child("child-2", 22L, "draft the summary")));
+
+        String out = tool.listSubagents(null);
+
+        assertTrue(out.contains("session_id=child-1"), out);
+        assertTrue(out.contains("session_id=child-2"), out);
+        assertTrue(out.contains("send_to_subagent"), out);
+        // Finished sessions stay discoverable even though the live registry is empty.
+        assertTrue(out.contains("idle"), out);
+    }
+
+    @Test
+    void overlaysLiveStatusOnPersistedSession() {
+        ToolExecutionContext.set("conv-root", "tester");
+        when(conversationMapper.selectList(any())).thenReturn(List.of(
+                child("child-1", 11L, "research the topic"),
+                child("child-2", 22L, "draft the summary")));
+        // child-2 is still running according to the live registry.
         registry.register("conv-root", "child-2", 22L, "draft the summary", null);
-        // A subagent under a different root must not leak into this listing.
-        registry.register("other-conv", "child-x", 99L, "unrelated work", null);
 
         String out = tool.listSubagents(null);
 
-        assertTrue(out.contains("Active sub-agents (2)"), "expected exactly two children, got: " + out);
-        assertTrue(out.contains("agent=11"), out);
-        assertTrue(out.contains("agent=22"), out);
-        assertTrue(out.contains("research the topic"), out);
-        assertTrue(out.contains("status=running"), out);
-        assertFalse(out.contains("agent=99"), "other conversation's subagent leaked: " + out);
+        assertTrue(out.contains("session_id=child-2"), out);
+        assertTrue(out.contains("running"), "live child should show running status: " + out);
+        // child-1 (no live record) renders as idle, child-2 as running — child-2 not duplicated.
+        assertEquals(1, out.split("session_id=child-2", -1).length - 1, "child-2 listed once: " + out);
     }
 
     @Test
     void prefersDelegationRootOverCurrentConversation() {
-        // Inside a delegated layer, the tree root is the human-facing conversation
-        // carried by the delegation frame, not the child's own conversation.
+        // Inside a delegated layer, the tree root is the human-facing conversation.
         ToolExecutionContext.set("child-conv", "tester");
         DelegationContext.enter("child-conv", java.util.Set.of(), "conv-root", "sa-1", 1);
         try {
-            registry.register("conv-root", "child-1", 11L, "research the topic", null);
+            when(conversationMapper.selectList(any())).thenReturn(List.of(child("child-1", 11L, "research")));
             String out = tool.listSubagents(null);
-            assertTrue(out.contains("Active sub-agents (1)"), out);
-            assertTrue(out.contains("agent=11"), out);
+            assertTrue(out.contains("session_id=child-1"), out);
+            assertFalse(out.contains("no conversation context"), out);
         } finally {
             DelegationContext.exit();
         }