diff --git a/changelog/unreleased/qoder-checkin-diagnostics.md b/changelog/unreleased/qoder-checkin-diagnostics.md
new file mode 100644
index 00000000..56500f1f
--- /dev/null
+++ b/changelog/unreleased/qoder-checkin-diagnostics.md
@@ -0,0 +1,7 @@
+### English
+
+- Qoder check-in: when upstream returns no claimable campaign, the log and the account card's check-in tooltip now show the campaign count and an `actionType:claimStatus` summary instead of only "not open"; a token renewal response that omits securityOauthToken / refreshToken no longer clears the held tokens. (#323)
+
+### 中文
+
+- Qoder 签到：上游未返回可领取活动时，日志与账号卡片签到提示会带上活动数与 `actionType:claimStatus` 摘要，而不再只显示"签到活动未开放"；token 续期响应缺少 securityOauthToken / refreshToken 时保留原值，不再被清空。（#323）
diff --git a/internal/providers/qoder/bridge.go b/internal/providers/qoder/bridge.go
index 9effc3dd..620675b9 100644
--- a/internal/providers/qoder/bridge.go
+++ b/internal/providers/qoder/bridge.go
@@ -332,9 +332,19 @@ func (b *Bridge) applyJobToken(jt map[string]any, userType string) {
 		SecurityOauthToken: securityOauth,
 		RefreshToken:       refreshToken,
 	}
-	sess := qauth.NewSession(identity, b.machineID, b.machineToken, b.machineType)
-
 	b.mu.Lock()
+	// A refresh response that omits a token must not erase the one we hold:
+	// an empty securityOauthToken would make check-in/quota fail with "token
+	// unavailable", and an empty refreshToken would break the next renewal.
+	if securityOauth == "" {
+		securityOauth = b.securityOath
+		identity.SecurityOauthToken = securityOauth
+	}
+	if refreshToken == "" {
+		refreshToken = b.refreshToken
+		identity.RefreshToken = refreshToken
+	}
+	sess := qauth.NewSession(identity, b.machineID, b.machineToken, b.machineType)
 	b.sess = sess
 	b.identity = &identity
 	b.refreshToken = refreshToken
diff --git a/internal/providers/qoder/bridge_token_test.go b/internal/providers/qoder/bridge_token_test.go
new file mode 100644
index 00000000..ab4c81bc
--- /dev/null
+++ b/internal/providers/qoder/bridge_token_test.go
@@ -0,0 +1,41 @@
+package qoder
+
+import (
+	"testing"
+	"time"
+)
+
+// A renewal response that omits securityOauthToken/refreshToken must keep the
+// previously held tokens instead of blanking them (#323).
+func TestApplyJobTokenKeepsTokensWhenRefreshOmitsThem(t *testing.T) {
+	b := newTestBridge(t, "fake-pat-secret-0123456789abcdef")
+	b.applyJobToken(map[string]any{
+		"id":         "test-uid-12345",
+		"name":       "tester",
+		"expireTime": float64(time.Now().Add(48 * time.Hour).UnixMilli()),
+	}, "personal_standard")
+	if got := b.CurrentSecurityOauth(); got != "test-security-oauth-token" {
+		t.Fatalf("securityOauth = %q, want previous token kept", got)
+	}
+	b.mu.Lock()
+	rt := b.refreshToken
+	ident := *b.identity
+	b.mu.Unlock()
+	if rt != "test-refresh-token" || ident.RefreshToken != "test-refresh-token" || ident.SecurityOauthToken != "test-security-oauth-token" {
+		t.Fatalf("tokens not preserved: rt=%q ident=%+v", rt, ident)
+	}
+}
+
+// A renewal that does carry new tokens must replace the old ones.
+func TestApplyJobTokenUsesNewTokens(t *testing.T) {
+	b := newTestBridge(t, "fake-pat-secret-0123456789abcdef")
+	b.applyJobToken(map[string]any{
+		"id":                 "test-uid-12345",
+		"securityOauthToken": "new-sot",
+		"refreshToken":       "new-rt",
+		"expireTime":         float64(time.Now().Add(48 * time.Hour).UnixMilli()),
+	}, "personal_standard")
+	if got := b.CurrentSecurityOauth(); got != "new-sot" {
+		t.Fatalf("securityOauth = %q want new-sot", got)
+	}
+}
diff --git a/internal/providers/qoder/checkin.go b/internal/providers/qoder/checkin.go
index 004579b6..01cf7dfd 100644
--- a/internal/providers/qoder/checkin.go
+++ b/internal/providers/qoder/checkin.go
@@ -9,6 +9,7 @@ import (
 	"errors"
 	"fmt"
 	"io"
+	"log"
 	"net/http"
 	"net/url"
 	"os"
@@ -204,7 +205,9 @@ func (b *Bridge) Checkin(ctx context.Context) (providers.CheckinResult, error) {
 	items := campaignsFrom(listRaw)
 	benefits := creditCampaigns(items)
 	if len(benefits) == 0 {
-		return providers.CheckinResult{Status: "skipped", Message: "签到活动未开放"}, nil
+		summary := campaignSummary(items)
+		log.Printf("[qoder-checkin] region=%s no credit campaigns: count=%d summary=%s", regionName(b.Region), len(items), summary)
+		return providers.CheckinResult{Status: "skipped", Message: skippedMessage("上游未返回可领取积分的签到活动", len(items), summary)}, nil
 	}
 	claimable := claimableCampaigns(benefits)
 	if len(claimable) == 0 {
@@ -213,7 +216,9 @@ func (b *Bridge) Checkin(ctx context.Context) (providers.CheckinResult, error) {
 				return providers.CheckinResult{Status: "already", Message: "今日已签到"}, nil
 			}
 		}
-		return providers.CheckinResult{Status: "skipped", Message: "签到活动未开放"}, nil
+		summary := campaignSummary(items)
+		log.Printf("[qoder-checkin] region=%s credit campaigns not claimable: count=%d summary=%s", regionName(b.Region), len(items), summary)
+		return providers.CheckinResult{Status: "skipped", Message: skippedMessage("签到活动当前不可领取", len(items), summary)}, nil
 	}
 
 	// 2) Claim each claimable campaign. A claim that returns a non-CLAIMED
@@ -510,3 +515,41 @@ func shortHash(s string) string {
 	sum := sha256.Sum256([]byte(s))
 	return hex.EncodeToString(sum[:])[:8]
 }
+
+// campaignSummary renders "actionType:claimStatus" pairs (no ids or tokens) so
+// a skipped check-in carries the upstream state that caused it instead of a
+// generic "not open" message. Capped to keep the persisted message short.
+func campaignSummary(items []campaign) string {
+	if len(items) == 0 {
+		return "none"
+	}
+	const maxItems = 8
+	parts := make([]string, 0, maxItems+1)
+	for i, c := range items {
+		if i == maxItems {
+			parts = append(parts, fmt.Sprintf("+%d", len(items)-maxItems))
+			break
+		}
+		action := strings.TrimSpace(c.ActionType)
+		if action == "" {
+			action = "unknown"
+		}
+		status := strings.TrimSpace(c.ClaimStatus)
+		if status == "" {
+			status = "none"
+		}
+		parts = append(parts, action+":"+status)
+	}
+	return strings.Join(parts, ",")
+}
+
+func skippedMessage(reason string, count int, summary string) string {
+	return fmt.Sprintf("%s（活动数 %d：%s）", reason, count, summary)
+}
+
+func regionName(r *qauth.RegionConfig) string {
+	if r == nil {
+		return ""
+	}
+	return r.Name
+}
diff --git a/internal/providers/qoder/checkin_inprocess_test.go b/internal/providers/qoder/checkin_inprocess_test.go
index 926263d1..ad12c634 100644
--- a/internal/providers/qoder/checkin_inprocess_test.go
+++ b/internal/providers/qoder/checkin_inprocess_test.go
@@ -174,7 +174,24 @@ func TestBridgeCheckinNoClaimable(t *testing.T) {
 			name:       "empty campaigns",
 			resp:       map[string]any{"campaigns": []map[string]any{}},
 			wantStatus: "skipped",
-			wantMsg:    "签到活动未开放",
+			wantMsg:    "上游未返回可领取积分的签到活动（活动数 0：none）",
+		},
+		{
+			name: "only non-credit campaigns",
+			resp: map[string]any{"campaigns": []map[string]any{
+				{"campaignId": "v1", "actionType": "VIEW", "claimStatus": "CLAIMABLE"},
+			}},
+			wantStatus: "skipped",
+			wantMsg:    "上游未返回可领取积分的签到活动（活动数 1：VIEW:CLAIMABLE）",
+		},
+		{
+			name: "credit campaign not claimable",
+			resp: map[string]any{"campaigns": []map[string]any{
+				{"campaignId": "c1", "actionType": "CLAIM_BENEFIT", "claimStatus": "LOCKED"},
+				{"campaignId": "c2", "actionType": "CLAIM_BENEFIT"},
+			}},
+			wantStatus: "skipped",
+			wantMsg:    "签到活动当前不可领取（活动数 2：CLAIM_BENEFIT:LOCKED,CLAIM_BENEFIT:none）",
 		},
 		{
 			name: "all claimed",