diff --git a/src/App.vue b/src/App.vue
index bf8558af82..d849be0458 100644
--- a/src/App.vue
+++ b/src/App.vue
@@ -15,6 +15,7 @@ import UpdateDialog from "@/components/layout/UpdateDialog.vue";
 import LoginPage from "@/components/auth/LoginPage.vue";
 import { useConnectionStore } from "@/stores/connectionStore";
 import { useQueryStore } from "@/stores/queryStore";
+import { useAgentRuntimeStore } from "@/stores/agentRuntimeStore";
 import { useSettingsStore } from "@/stores/settingsStore";
 import { useSavedSqlStore } from "@/stores/savedSqlStore";
 import { useToast } from "@/composables/useToast";
@@ -46,6 +47,7 @@ import type { HistoryEntry } from "@/lib/tauri";
 const { t } = useI18n();
 const connectionStore = useConnectionStore();
 const queryStore = useQueryStore();
+const agentRuntimeStore = useAgentRuntimeStore();
 const settingsStore = useSettingsStore();
 const savedSqlStore = useSavedSqlStore();
 const { message: toastMessage, visible: toastVisible, toast } = useToast();
@@ -158,6 +160,7 @@ watch(
   () => queryStore.activeTabId,
   () => {
     selectedSql.value = "";
+    agentRuntimeStore.setSelectedSql("");
     activeOutputView.value = "result";
   },
 );
@@ -614,7 +617,12 @@ onUnmounted(() => {
                       if (queryStore.activeTabId) queryStore.updateSql(queryStore.activeTabId, v);
                     }
                   "
-                  @editor-selection-change="(v: string) => (selectedSql = v)"
+                  @editor-selection-change="
+                    (v: string) => {
+                      selectedSql = v;
+                      agentRuntimeStore.setSelectedSql(v);
+                    }
+                  "
                   @editor-cursor-change="(p: number) => (cursorPos = p)"
                   @format-error="toast(t('toolbar.formatSqlFailed'))"
                   @reload="
diff --git a/src/components/grid/DataGrid.vue b/src/components/grid/DataGrid.vue
index 9e5a6e644f..3b115df733 100644
--- a/src/components/grid/DataGrid.vue
+++ b/src/components/grid/DataGrid.vue
@@ -62,9 +62,17 @@ import type { QueryResult, ColumnInfo, DatabaseType } from "@/types/database";
 import * as api from "@/lib/api";
 import { buildTableSelectSql, quoteTableIdentifier } from "@/lib/tableSelectSql";
 import { isHiddenGridColumn, usesSyntheticRowIdKey } from "@/lib/tableEditing";
-import { formatGridSqlLiteral } from "@/lib/dataGridSql";
-import { matchesRowStatusFilter, type RowStatus, type RowStatusFilter } from "@/lib/gridRowStatus";
 import { displayCellValue, type CellValue } from "@/lib/cellValue";
+import { buildDataGridSaveStatements, formatGridSqlLiteral } from "@/lib/dataGridSql";
+import { formatMarkdownTable } from "@/lib/markdownTable";
+import { buildXlsxWorkbook } from "@/lib/xlsxExport";
+import {
+  matchesRowStatusFilter,
+  rowStatusFilterAfterAddingRow,
+  type RowStatus,
+  type RowStatusFilter,
+} from "@/lib/gridRowStatus";
+import { useAgentRuntimeStore } from "@/stores/agentRuntimeStore";
 
 import { useToast } from "@/composables/useToast";
 import { useDataGridExport } from "@/composables/useDataGridExport";
@@ -74,6 +82,7 @@ import { useDataGridEditor } from "@/composables/useDataGridEditor";
 
 const { t } = useI18n();
 const { toast } = useToast();
+const agentRuntimeStore = useAgentRuntimeStore();
 
 const props = defineProps<{
   result: QueryResult;
@@ -1090,6 +1099,22 @@ const activeCellDetail = computed(() => {
 const detailEditValue = ref("");
 const isEditingDetail = ref(false);
 
+watch(
+  selectedCells,
+  (data) => {
+    agentRuntimeStore.setSelection(
+      selectedCellCount.value > 0
+        ? {
+            type: "grid-cells",
+            range: selectedRange.value,
+            data,
+          }
+        : { type: "none" },
+    );
+  },
+  { deep: true },
+);
+
 function startDetailEdit() {
   const detail = activeCellDetail.value;
   if (!detail || !detail.isEditable) return;
@@ -1611,6 +1636,7 @@ watch(
 
 onUnmounted(() => {
   cleanupFrames();
+  agentRuntimeStore.setSelection({ type: "none" });
   onDdlResizeEnd();
   finishCellSelection();
   clearTimeout(_searchTimer);
diff --git a/src/lib/agentRuntimeSnapshot.ts b/src/lib/agentRuntimeSnapshot.ts
new file mode 100644
index 0000000000..5494863fd8
--- /dev/null
+++ b/src/lib/agentRuntimeSnapshot.ts
@@ -0,0 +1,62 @@
+import type { ConnectionConfig, QueryResult, QueryTab } from "@/types/database";
+
+export const DEFAULT_RESULT_SAMPLE_LIMIT = 50;
+
+export interface RuntimeResultSample {
+  columns: string[];
+  rows: QueryResult["rows"];
+  truncated: boolean;
+  executionTimeMs: number;
+  sampleLimit: number;
+}
+
+export interface AgentRuntimeSnapshot {
+  activeConnectionId?: string;
+  activeConnectionName?: string;
+  database?: string;
+  schema?: string;
+  activeTabId?: string;
+  activeTabTitle?: string;
+  sql?: string;
+  selectedSql?: string;
+  selection: unknown;
+  result?: RuntimeResultSample;
+}
+
+export interface BuildAgentRuntimeSnapshotOptions {
+  tabs: QueryTab[];
+  activeTabId: string | null;
+  getConnection: (connectionId: string) => Pick<ConnectionConfig, "name"> | undefined;
+  selectedSql?: string;
+  selection?: unknown;
+  resultSampleLimit?: number;
+}
+
+export function buildAgentRuntimeSnapshot(options: BuildAgentRuntimeSnapshotOptions): AgentRuntimeSnapshot {
+  const tab = options.tabs.find((item) => item.id === options.activeTabId);
+  const conn = tab ? options.getConnection(tab.connectionId) : undefined;
+  const selectedSql = options.selectedSql?.trim();
+  const limit = options.resultSampleLimit ?? DEFAULT_RESULT_SAMPLE_LIMIT;
+  const result = tab?.result
+    ? {
+        columns: tab.result.columns,
+        rows: tab.result.rows.slice(0, limit),
+        truncated: tab.result.rows.length > limit || !!tab.result.truncated,
+        executionTimeMs: tab.result.execution_time_ms,
+        sampleLimit: limit,
+      }
+    : undefined;
+
+  return {
+    activeConnectionId: tab?.connectionId,
+    activeConnectionName: conn?.name,
+    database: tab?.database,
+    schema: tab?.schema,
+    activeTabId: tab?.id,
+    activeTabTitle: tab?.title,
+    sql: tab?.sql,
+    selectedSql: selectedSql || undefined,
+    selection: options.selection ?? { type: "none" },
+    result,
+  };
+}
diff --git a/src/lib/api.ts b/src/lib/api.ts
index 86fa229dd3..0098c528df 100644
--- a/src/lib/api.ts
+++ b/src/lib/api.ts
@@ -72,6 +72,10 @@ export const executeScript = forward("executeScript");
 export const executeInTransaction = forward("executeInTransaction");
 export const cancelQuery = forward("cancelQuery");
 
+// Agent Runtime
+export const agentRuntimeUpdateSnapshot = forward("agentRuntimeUpdateSnapshot");
+export const agentRuntimeLoadHandoffs = forward("agentRuntimeLoadHandoffs");
+
 // AI
 export const aiComplete = forward("aiComplete");
 export const aiStream = forward("aiStream");
diff --git a/src/lib/http.ts b/src/lib/http.ts
index 6fdfb977ab..148a68f71f 100644
--- a/src/lib/http.ts
+++ b/src/lib/http.ts
@@ -39,6 +39,7 @@ import type {
   TableImportSummary,
   TableImportProgress,
 } from "./tauri";
+import type { AgentRuntimeSnapshot } from "@/lib/agentRuntimeSnapshot";
 
 // ---------------------------------------------------------------------------
 // Helpers
@@ -290,6 +291,12 @@ export async function cancelQuery(executionId: string): Promise<boolean> {
   return post("/api/query/cancel", { executionId });
 }
 
+export async function agentRuntimeUpdateSnapshot(_snapshot: AgentRuntimeSnapshot): Promise<void> {}
+
+export async function agentRuntimeLoadHandoffs(): Promise<unknown[]> {
+  return [];
+}
+
 // ---------------------------------------------------------------------------
 // AI
 // ---------------------------------------------------------------------------
diff --git a/src/lib/tauri.ts b/src/lib/tauri.ts
index 1c2906ffcb..2be0e47a67 100644
--- a/src/lib/tauri.ts
+++ b/src/lib/tauri.ts
@@ -19,6 +19,7 @@ import type {
   SavedSqlFolder,
   SavedSqlLibrary,
 } from "@/types/database";
+import type { AgentRuntimeSnapshot } from "@/lib/agentRuntimeSnapshot";
 import type { AiConfig } from "@/stores/settingsStore";
 
 export interface AiMessage {
@@ -80,6 +81,14 @@ export async function loadAiConfig(): Promise<AiConfig | null> {
   return invoke("load_ai_config");
 }
 
+export async function agentRuntimeUpdateSnapshot(snapshot: AgentRuntimeSnapshot): Promise<void> {
+  return invoke("agent_runtime_update_snapshot", { snapshot });
+}
+
+export async function agentRuntimeLoadHandoffs(): Promise<unknown[]> {
+  return invoke("agent_runtime_load_handoffs");
+}
+
 // --- AI Conversations ---
 
 export interface AiChatMessage {
diff --git a/src/stores/agentRuntimeStore.ts b/src/stores/agentRuntimeStore.ts
new file mode 100644
index 0000000000..97d7f38be5
--- /dev/null
+++ b/src/stores/agentRuntimeStore.ts
@@ -0,0 +1,51 @@
+import { defineStore } from "pinia";
+import { ref } from "vue";
+import * as api from "@/lib/api";
+import { buildAgentRuntimeSnapshot, DEFAULT_RESULT_SAMPLE_LIMIT } from "@/lib/agentRuntimeSnapshot";
+import { useConnectionStore } from "@/stores/connectionStore";
+import { useQueryStore } from "@/stores/queryStore";
+
+export const useAgentRuntimeStore = defineStore("agentRuntime", () => {
+  const selection = ref<unknown>({ type: "none" });
+  const selectedSql = ref("");
+  let timer: ReturnType<typeof setTimeout> | null = null;
+
+  function setSelection(value: unknown) {
+    selection.value = value;
+    scheduleSync();
+  }
+
+  function setSelectedSql(value: string) {
+    selectedSql.value = value;
+    scheduleSync();
+  }
+
+  function scheduleSync() {
+    if (timer) clearTimeout(timer);
+    timer = setTimeout(() => {
+      timer = null;
+      void syncNow();
+    }, 100);
+  }
+
+  async function syncNow() {
+    const connectionStore = useConnectionStore();
+    const queryStore = useQueryStore();
+    const snapshot = buildAgentRuntimeSnapshot({
+      tabs: queryStore.tabs,
+      activeTabId: queryStore.activeTabId,
+      getConnection: (connectionId) => connectionStore.getConfig(connectionId),
+      selectedSql: selectedSql.value,
+      selection: selection.value,
+      resultSampleLimit: DEFAULT_RESULT_SAMPLE_LIMIT,
+    });
+
+    try {
+      await api.agentRuntimeUpdateSnapshot(snapshot);
+    } catch (err) {
+      console.debug("[DBX] Agent runtime snapshot sync skipped:", err);
+    }
+  }
+
+  return { selection, selectedSql, setSelection, setSelectedSql, scheduleSync, syncNow };
+});
diff --git a/src/stores/queryStore.ts b/src/stores/queryStore.ts
index d3094ddb9e..4532c5b425 100644
--- a/src/stores/queryStore.ts
+++ b/src/stores/queryStore.ts
@@ -10,6 +10,7 @@ import { analyzeEditableQuery, allPrimaryKeysPresent } from "@/lib/sqlAnalysis";
 import { restoreOpenTabsState, serializeOpenTabs } from "@/lib/openTabsPersistence";
 import * as api from "@/lib/api";
 import { useConnectionStore } from "@/stores/connectionStore";
+import { useAgentRuntimeStore } from "@/stores/agentRuntimeStore";
 import { isTauriRuntime } from "@/lib/tauriRuntime";
 import type { SavedSqlFile } from "@/types/database";
 
@@ -72,11 +73,18 @@ export const useQueryStore = defineStore("query", () => {
     return tabs.value.find((t) => t.connectionId === connectionId && t.database === database && t.title === title);
   }
 
+  function scheduleAgentRuntimeSync() {
+    useAgentRuntimeStore().scheduleSync();
+  }
+
+  watch(activeTabId, () => scheduleAgentRuntimeSync());
+
   function createTab(connectionId: string, database: string, title?: string, mode: QueryTab["mode"] = "query") {
     if (title) {
       const existing = findTabByTitle(connectionId, database, title);
       if (existing) {
         activeTabId.value = existing.id;
+        scheduleAgentRuntimeSync();
         return existing.id;
       }
     }
@@ -95,6 +103,7 @@ export const useQueryStore = defineStore("query", () => {
     };
     tabs.value.push(tab);
     activeTabId.value = id;
+    scheduleAgentRuntimeSync();
     return id;
   }
 
@@ -145,6 +154,7 @@ export const useQueryStore = defineStore("query", () => {
     if (activeTabId.value === id) {
       activeTabId.value = tabs.value[Math.min(idx, tabs.value.length - 1)]?.id ?? null;
     }
+    scheduleAgentRuntimeSync();
   }
 
   function closeOtherTabs(id: string) {
@@ -153,6 +163,7 @@ export const useQueryStore = defineStore("query", () => {
     const next = closeOtherTabsState(tabs.value, activeTabId.value, id);
     tabs.value = next.tabs;
     activeTabId.value = next.activeTabId;
+    scheduleAgentRuntimeSync();
   }
 
   function closeAllTabs() {
@@ -161,6 +172,7 @@ export const useQueryStore = defineStore("query", () => {
     const next = closeAllTabsState(tabs.value, activeTabId.value);
     tabs.value = next.tabs;
     activeTabId.value = next.activeTabId;
+    scheduleAgentRuntimeSync();
   }
 
   function updateSql(id: string, sql: string) {
@@ -169,6 +181,7 @@ export const useQueryStore = defineStore("query", () => {
       tab.sql = sql;
       tab.resultSortedSql = undefined;
       tab.resultBaseSql = undefined;
+      scheduleAgentRuntimeSync();
     }
   }
 
@@ -183,6 +196,7 @@ export const useQueryStore = defineStore("query", () => {
     const existing = tabs.value.find((tab) => tab.savedSqlId === file.id);
     if (existing) {
       activeTabId.value = existing.id;
+      scheduleAgentRuntimeSync();
       return existing.id;
     }
 
@@ -202,6 +216,7 @@ export const useQueryStore = defineStore("query", () => {
     };
     tabs.value.push(tab);
     activeTabId.value = id;
+    scheduleAgentRuntimeSync();
     return id;
   }
 
@@ -224,6 +239,7 @@ export const useQueryStore = defineStore("query", () => {
     tab.resultSortedSql = undefined;
     clearExplain(tab);
     tab.tableMeta = undefined;
+    scheduleAgentRuntimeSync();
   }
 
   function updateSchema(id: string, schema: string | undefined) {
@@ -231,6 +247,7 @@ export const useQueryStore = defineStore("query", () => {
     if (!tab || tab.schema === schema) return;
     tab.schema = schema;
     if (tab.mode === "objects") tab.objectBrowser = { ...tab.objectBrowser, schema };
+    scheduleAgentRuntimeSync();
   }
 
   function updateConnection(id: string, connectionId: string, database = "") {
@@ -245,6 +262,7 @@ export const useQueryStore = defineStore("query", () => {
     tab.resultSortedSql = undefined;
     clearExplain(tab);
     tab.tableMeta = undefined;
+    scheduleAgentRuntimeSync();
   }
 
   function setTableMeta(id: string, meta: NonNullable<QueryTab["tableMeta"]>) {
@@ -410,6 +428,7 @@ export const useQueryStore = defineStore("query", () => {
         console.info("[DBX][executeTabSql:metadata:start]", { traceId, elapsed: elapsed() });
         await analyzeQueryMetadata(current, current.resultBaseSql);
         console.info("[DBX][executeTabSql:metadata:done]", { traceId, elapsed: elapsed() });
+        scheduleAgentRuntimeSync();
       } else {
         console.warn("[DBX][executeTabSql:stale-result]", {
           traceId,
@@ -428,6 +447,7 @@ export const useQueryStore = defineStore("query", () => {
         if (current.mode !== "data") current.tableMeta = undefined;
         current.resultBaseSql = options?.resultBaseSql ?? sql;
         current.resultSortedSql = options?.resultSortedSql;
+        scheduleAgentRuntimeSync();
       }
     } finally {
       const current = tabs.value.find((t) => t.id === id);
@@ -538,6 +558,7 @@ export const useQueryStore = defineStore("query", () => {
     if (!tab?.results || index < 0 || index >= tab.results.length) return;
     tab.activeResultIndex = index;
     tab.result = tab.results[index];
+    scheduleAgentRuntimeSync();
   }
 
   function trimResultCache() {
diff --git a/tests/agentRuntimeSnapshot.test.ts b/tests/agentRuntimeSnapshot.test.ts
new file mode 100644
index 0000000000..3b02ddf167
--- /dev/null
+++ b/tests/agentRuntimeSnapshot.test.ts
@@ -0,0 +1,80 @@
+import { strict as assert } from "node:assert";
+import test from "node:test";
+import { buildAgentRuntimeSnapshot } from "../src/lib/agentRuntimeSnapshot.ts";
+
+test("builds runtime snapshot from active tab, selection, and limited result rows", () => {
+  const snapshot = buildAgentRuntimeSnapshot({
+    tabs: [
+      {
+        id: "tab-1",
+        title: "Orders",
+        connectionId: "conn-1",
+        database: "sales",
+        schema: "public",
+        sql: "select * from orders",
+        result: {
+          columns: ["id"],
+          rows: [[1], [2], [3]],
+          affected_rows: 0,
+          execution_time_ms: 12,
+        },
+        isExecuting: false,
+        mode: "query",
+      },
+    ],
+    activeTabId: "tab-1",
+    getConnection: (id) => (id === "conn-1" ? { name: "Prod Sales" } : undefined),
+    selectedSql: "select *",
+    selection: {
+      type: "grid-cells",
+      data: { columns: ["id"], rows: [[1]] },
+    },
+    resultSampleLimit: 2,
+  });
+
+  assert.deepEqual(snapshot, {
+    activeConnectionId: "conn-1",
+    activeConnectionName: "Prod Sales",
+    database: "sales",
+    schema: "public",
+    activeTabId: "tab-1",
+    activeTabTitle: "Orders",
+    sql: "select * from orders",
+    selectedSql: "select *",
+    selection: {
+      type: "grid-cells",
+      data: { columns: ["id"], rows: [[1]] },
+    },
+    result: {
+      columns: ["id"],
+      rows: [[1], [2]],
+      truncated: true,
+      executionTimeMs: 12,
+      sampleLimit: 2,
+    },
+  });
+});
+
+test("omits empty selected SQL and marks empty UI selection as none", () => {
+  const snapshot = buildAgentRuntimeSnapshot({
+    tabs: [
+      {
+        id: "tab-2",
+        title: "Scratch",
+        connectionId: "conn-2",
+        database: "",
+        sql: "",
+        isExecuting: false,
+        mode: "query",
+      },
+    ],
+    activeTabId: "tab-2",
+    getConnection: () => ({ name: "Local" }),
+    selectedSql: "   ",
+    resultSampleLimit: 50,
+  });
+
+  assert.equal(snapshot.selectedSql, undefined);
+  assert.deepEqual(snapshot.selection, { type: "none" });
+  assert.equal(snapshot.result, undefined);
+});