diff --git a/activity.go b/activity.go
index 2c2106a..abf9bd3 100644
--- a/activity.go
+++ b/activity.go
@@ -12,19 +12,52 @@ import "time"
 type ActivityCard struct {
 	ID ID `json:"id"`
 	// ProjectID/ConversationID 定位归属；ConversationID 为空表示项目级卡片（远期跨会话收件箱）。
-	ProjectID      ID     `json:"projectId"`
-	ConversationID ID     `json:"conversationId,omitempty"`
-	SourceRunID    ID     `json:"sourceRunId,omitempty"`    // 溯源：产生卡片的 run
-	AnchorMessageID ID    `json:"anchorMessageId,omitempty"` // 互定位：出生消息（↙ 定位到对话）
-	Kind           CardKind   `json:"kind"`
-	Title          string     `json:"title"`
-	Status         CardStatus `json:"status"`
-	Tone           string     `json:"tone,omitempty"` // ok | warn | danger | info
-	Body           []UINode   `json:"body,omitempty"`
-	Actions        []UIAction `json:"actions,omitempty"` // 走命令总线；未绑定 command 降级为发消息
-	Pinned         bool       `json:"pinned,omitempty"`
-	CreatedAt      time.Time  `json:"createdAt"`
-	UpdatedAt      time.Time  `json:"updatedAt"`
+	ProjectID       ID         `json:"projectId"`
+	ConversationID  ID         `json:"conversationId,omitempty"`
+	SourceRunID     ID         `json:"sourceRunId,omitempty"`     // 溯源：产生卡片的 run
+	AnchorMessageID ID         `json:"anchorMessageId,omitempty"` // 互定位：出生消息（↙ 定位到对话）
+	Kind            CardKind   `json:"kind"`
+	Title           string     `json:"title"`
+	Status          CardStatus `json:"status"`
+	Tone            string     `json:"tone,omitempty"` // ok | warn | danger | info
+	Body            []UINode   `json:"body,omitempty"`
+	Actions         []UIAction `json:"actions,omitempty"` // 走命令总线；未绑定 command 降级为发消息
+	Pinned          bool       `json:"pinned,omitempty"`
+	Work            *WorkCard  `json:"work,omitempty"` // optional background-work snapshot; never a foreground approval
+	CreatedAt       time.Time  `json:"createdAt"`
+	UpdatedAt       time.Time  `json:"updatedAt"`
+}
+
+// WorkCard keeps the complete saved result and an optional, non-blocking next step
+// on the original task. Reading and answering do not change the result version.
+type WorkCard struct {
+	Result        string        `json:"result,omitempty"`
+	ResultVersion int           `json:"resultVersion"`
+	ReadVersion   int           `json:"readVersion"`
+	CompletedAt   *time.Time    `json:"completedAt,omitempty"`
+	Decision      *WorkDecision `json:"decision,omitempty"`
+}
+
+type WorkDecision struct {
+	RunID       ID           `json:"runId,omitempty"` // reserved child identity; reconciles acceptance after restart without rerunning
+	Mode        string       `json:"mode"`            // single | multiple
+	State       string       `json:"state"`           // open | deferred | dispatching | submitted
+	Options     []WorkOption `json:"options,omitempty"`
+	SelectedIDs []string     `json:"selectedIds,omitempty"`
+	FreeText    string       `json:"freeText,omitempty"`
+	RespondedAt *time.Time   `json:"respondedAt,omitempty"`
+}
+
+type WorkOption struct {
+	ID    string `json:"id"`
+	Label string `json:"label"`
+}
+
+// WorkCardAction is version-fenced. Presentation-only opens never mark a result read.
+type WorkCardAction struct {
+	ResultVersion int      `json:"resultVersion"`
+	SelectedIDs   []string `json:"selectedIds,omitempty"`
+	FreeText      string   `json:"freeText,omitempty"`
 }
 
 type CardKind string
diff --git a/activity_work_test.go b/activity_work_test.go
new file mode 100644
index 0000000..ad4fced
--- /dev/null
+++ b/activity_work_test.go
@@ -0,0 +1,46 @@
+package core
+
+import (
+	"encoding/json"
+	"strings"
+	"testing"
+	"time"
+)
+
+func TestWorkCardSurvivesPersistedSnapshot(t *testing.T) {
+	completed := time.Date(2026, 10, 15, 6, 0, 0, 0, time.UTC)
+	card := ActivityCard{ID: "card_work", Status: CardDone, Work: &WorkCard{
+		Result:        strings.Repeat("完整结果\n", 200) + "最后一项依据",
+		ResultVersion: 2, ReadVersion: 1, CompletedAt: &completed,
+		Decision: &WorkDecision{Mode: "multiple", State: "submitted", Options: []WorkOption{{ID: "summary", Label: "生成摘要"}},
+			SelectedIDs: []string{"summary"}, FreeText: "请突出关键限制", RespondedAt: &completed},
+	}}
+	data, err := json.Marshal(card)
+	if err != nil {
+		t.Fatal(err)
+	}
+	var restored ActivityCard
+	if err := json.Unmarshal(data, &restored); err != nil {
+		t.Fatal(err)
+	}
+	if restored.Work == nil || restored.Work.Result != card.Work.Result || restored.Work.ReadVersion != 1 || restored.Work.ResultVersion != 2 {
+		t.Fatalf("complete result or unread version lost: %+v", restored.Work)
+	}
+	if d := restored.Work.Decision; d.State != "submitted" || d.SelectedIDs[0] != "summary" || d.FreeText != "请突出关键限制" || !d.RespondedAt.Equal(completed) {
+		t.Fatalf("decision history lost: %+v", d)
+	}
+}
+
+func TestLegacyCardOmitsOptionalWork(t *testing.T) {
+	var legacy ActivityCard
+	if err := json.Unmarshal([]byte(`{"id":"old","status":"resolved","body":[{"type":"markdown","markdown":"保留历史"}]}`), &legacy); err != nil {
+		t.Fatal(err)
+	}
+	data, err := json.Marshal(legacy)
+	if err != nil {
+		t.Fatal(err)
+	}
+	if legacy.Work != nil || strings.Contains(string(data), `"work"`) || legacy.Body[0].Markdown != "保留历史" {
+		t.Fatalf("legacy payload changed: %s", data)
+	}
+}
diff --git a/ts/types.ts b/ts/types.ts
index 254cb6f..de1ef69 100644
--- a/ts/types.ts
+++ b/ts/types.ts
@@ -150,7 +150,21 @@ export interface ActivityCard {
   sourceRunId?: ID; anchorMessageId?: ID;
   kind: CardKind; title: string; status: CardStatus; tone?: string;
   body?: UINode[]; actions?: { id: string; label: string; style?: 'primary' | 'default' | 'danger'; command?: string }[];
-  pinned?: boolean; createdAt: string; updatedAt: string;
+  pinned?: boolean; createdAt: string; updatedAt: string; work?: WorkCard;
+}
+
+export interface WorkCard {
+  result?: string; resultVersion: number; readVersion: number; completedAt?: string;
+  decision?: WorkDecision;
+}
+export interface WorkDecision {
+  runId?: ID;
+  mode: 'single' | 'multiple'; state: 'open' | 'deferred' | 'dispatching' | 'submitted';
+  options?: { id: string; label: string }[];
+  selectedIds?: string[]; freeText?: string; respondedAt?: string;
+}
+export interface WorkCardAction {
+  resultVersion: number; selectedIds?: string[]; freeText?: string;
 }
 
 export interface CardPayload { card: ActivityCard }