diff --git a/mateclaw-server/src/main/java/vip/mate/memory/search/SessionSearchTool.java b/mateclaw-server/src/main/java/vip/mate/memory/search/SessionSearchTool.java
index dfc22605..cc10f0b4 100644
--- a/mateclaw-server/src/main/java/vip/mate/memory/search/SessionSearchTool.java
+++ b/mateclaw-server/src/main/java/vip/mate/memory/search/SessionSearchTool.java
@@ -38,7 +38,7 @@ public class SessionSearchTool {
             注意：只会搜索已完成的会话，不会返回当前正在运行中的其他会话内容。
             """)
     public String session_search(
-            @ToolParam(description = "当前 Agent 的 ID") Long agentId,
+            @ToolParam(description = "当前 Agent 的 ID。必须作为字符串传入，避免大整数精度丢失") String agentId,
             @ToolParam(description = "搜索模式：recent 或 search") String mode,
             @ToolParam(description = "搜索关键词（mode=search 时必填）", required = false) String query,
             @ToolParam(description = "返回结果数量上限，默认 10", required = false) Integer limit,
@@ -64,13 +64,14 @@ public class SessionSearchTool {
         int effectiveLimit = limit != null && limit > 0 ? limit : 10;
 
         try {
+            Long parsedAgentId = parseAgentId(agentId);
             if ("recent".equalsIgnoreCase(mode.trim())) {
-                return handleRecent(agentId, currentConversationId, effectiveLimit);
+                return handleRecent(parsedAgentId, currentConversationId, effectiveLimit);
             } else if ("search".equalsIgnoreCase(mode.trim())) {
                 if (query == null || query.isBlank()) {
                     return error("mode=search 时 query 不能为空");
                 }
-                return handleSearch(agentId, currentConversationId, query, effectiveLimit);
+                return handleSearch(parsedAgentId, currentConversationId, query, effectiveLimit);
             } else {
                 return error("无效的 mode: " + mode + "，请使用 recent 或 search");
             }
@@ -117,4 +118,16 @@ public class SessionSearchTool {
         result.set("message", message);
         return JSONUtil.toJsonPrettyStr(result);
     }
+
+    private Long parseAgentId(String agentId) {
+        String trimmed = agentId != null ? agentId.trim() : "";
+        if (trimmed.isEmpty()) {
+            throw new IllegalArgumentException("agentId 不能为空");
+        }
+        try {
+            return Long.parseLong(trimmed);
+        } catch (NumberFormatException e) {
+            throw new IllegalArgumentException("agentId 必须是数字字符串");
+        }
+    }
 }
diff --git a/mateclaw-server/src/test/java/vip/mate/memory/search/SessionSearchToolIdSchemaTest.java b/mateclaw-server/src/test/java/vip/mate/memory/search/SessionSearchToolIdSchemaTest.java
new file mode 100644
index 00000000..0a35d6ae
--- /dev/null
+++ b/mateclaw-server/src/test/java/vip/mate/memory/search/SessionSearchToolIdSchemaTest.java
@@ -0,0 +1,35 @@
+package vip.mate.memory.search;
+
+import com.fasterxml.jackson.databind.JsonNode;
+import com.fasterxml.jackson.databind.ObjectMapper;
+import org.junit.jupiter.api.DisplayName;
+import org.junit.jupiter.api.Test;
+import org.springframework.ai.support.ToolCallbacks;
+import org.springframework.ai.tool.ToolCallback;
+
+import static org.assertj.core.api.Assertions.assertThat;
+import static org.mockito.Mockito.mock;
+
+class SessionSearchToolIdSchemaTest {
+    private static final ObjectMapper MAPPER = new ObjectMapper();
+
+    @Test
+    @DisplayName("session_search publishes agentId as a string parameter so LLM tool calls preserve precision")
+    void sessionSearchAgentIdSchemaIsString() throws Exception {
+        SessionSearchTool tool = new SessionSearchTool(mock(SessionSearchService.class));
+
+        String schema = callback(tool, "session_search").getToolDefinition().inputSchema();
+        JsonNode root = MAPPER.readTree(schema);
+
+        assertThat(root.at("/properties/agentId/type").asText()).isEqualTo("string");
+    }
+
+    private static ToolCallback callback(Object tool, String name) {
+        for (ToolCallback callback : ToolCallbacks.from(tool)) {
+            if (name.equals(callback.getToolDefinition().name())) {
+                return callback;
+            }
+        }
+        throw new AssertionError("Missing tool callback: " + name);
+    }
+}