diff --git a/.task/feature-conversation-handoff.md b/.task/feature-conversation-handoff.md
index 8c7ec0bb..77d5a194 100644
--- a/.task/feature-conversation-handoff.md
+++ b/.task/feature-conversation-handoff.md
@@ -205,3 +205,80 @@
 
 - 局部恢复已通过并导入：`/tmp/pr651-resume-20261020-a6.json`（LOCAL_READY，SELF）；正式交付需新鲜同步与固定 HEAD CI。
 - 新 repair 单元：`ci-pg-async-completion-r2`；固定 Backend base `e927694818f3c0b79ec663d70ab2aa9d47d8fd8f`；工作包 `/tmp/pr651-repair-unit-r2.json`；收据目标 `/tmp/pr651-repair-r2.json`；运行中，尚无成功产物。
+
+<!-- Local receipt: SELF. Digests detect corruption; they do not authenticate a reviewer or CI. -->
+```json
+{
+  "summary_schema": 1,
+  "source": "SELF",
+  "timestamp": "2026-10-20T09:09:46.106201+00:00",
+  "command": "cd /home/weichen/projects/Agent-System-Backend-wt-fix-ci-pg-flaky-tests && git rev-parse HEAD && GOWORK=off go vet ./... && GOWORK=off go test -count=1 ./...",
+  "exit_code": 0,
+  "cwd": "/home/weichen/projects/Agent-System-Dev-wt-feature-conversation-handoff",
+  "before_head": "4544cd94f8ece209b32aec885a410e5eeaef968e",
+  "after_head": "4544cd94f8ece209b32aec885a410e5eeaef968e",
+  "branch": "feature/conversation-handoff",
+  "target_branch": "main",
+  "target_head": "17f8bc06c110014b9101e7a33729d9f5445bd123",
+  "root_target": "main",
+  "immediate_target": "main",
+  "before_tracked_diff_sha256": "e3b0c44298fc1c149afbf4c8996fb92427ae41e4649b934ca495991b7852b855",
+  "after_tracked_diff_sha256": "e3b0c44298fc1c149afbf4c8996fb92427ae41e4649b934ca495991b7852b855",
+  "output_tail": [
+    "ok  \tagent-system-backend/internal/runtime\t1.834s",
+    "ok  \tagent-system-backend/internal/server\t28.474s",
+    "ok  \tagent-system-backend/internal/settings\t0.211s",
+    "ok  \tagent-system-backend/internal/skills\t1.741s",
+    "ok  \tagent-system-backend/internal/squadadapter\t0.158s",
+    "ok  \tagent-system-backend/internal/store\t12.820s",
+    "ok  \tagent-system-backend/internal/surfacesvc\t0.399s",
+    "ok  \tagent-system-backend/internal/tools\t13.619s",
+    "ok  \tagent-system-backend/internal/vision\t0.003s",
+    "ok  \tagent-system-backend/internal/wfcompile\t0.050s",
+    "ok  \tagent-system-backend/internal/workflow\t0.002s",
+    "ok  \tagent-system-backend/pkg/extension\t0.004s",
+    "ok  \tagent-system-backend/pkg/extension/link\t0.006s",
+    "ok  \tagent-system-backend/pkg/identity\t0.095s",
+    "?   \tagent-system-backend/web\t[no test files]"
+  ],
+  "output_sha256": "08769f0589e95d0b7878ce3551b931aceae5f80ad4916cc5f64bfd53ae5cfbb0",
+  "receipt_sha256": "d0a0fa46d65618338b88d99c72e53402449454c740fe7399d6354b7a80f5d084",
+  "receipt_path": "/home/weichen/.cache/agent-system-dev/evidence/d0a0fa46d65618338b88d99c72e53402449454c740fe7399d6354b7a80f5d084.json"
+}
+```
+
+<!-- Local receipt: SELF. Digests detect corruption; they do not authenticate a reviewer or CI. -->
+```json
+{
+  "summary_schema": 1,
+  "source": "SELF",
+  "timestamp": "2026-10-20T09:13:47.514647+00:00",
+  "command": "cd /home/weichen/projects/Agent-System-Backend-wt-fix-ci-pg-flaky-tests && git rev-parse HEAD && git diff --check origin/main HEAD && GOWORK=off go test ./internal/server ./internal/runmgr -run \"^(TestArtifactFacadeCard|TestMockCardflowFullLoop|TestMockCardflowStreamLoop|TestBackground.*|TestProjectEvents.*|TestUnregisteredProjectEventsRetainLegacyReads)$\" -count=1",
+  "exit_code": 0,
+  "cwd": "/home/weichen/projects/Agent-System-Dev-wt-feature-conversation-handoff",
+  "before_head": "4544cd94f8ece209b32aec885a410e5eeaef968e",
+  "after_head": "4544cd94f8ece209b32aec885a410e5eeaef968e",
+  "branch": "feature/conversation-handoff",
+  "target_branch": "main",
+  "target_head": "17f8bc06c110014b9101e7a33729d9f5445bd123",
+  "root_target": "main",
+  "immediate_target": "main",
+  "before_tracked_diff_sha256": "e3b0c44298fc1c149afbf4c8996fb92427ae41e4649b934ca495991b7852b855",
+  "after_tracked_diff_sha256": "e3b0c44298fc1c149afbf4c8996fb92427ae41e4649b934ca495991b7852b855",
+  "output_tail": [
+    "910d8e5fd20747eebc6e53b5fc0118185cb53765",
+    "ok  \tagent-system-backend/internal/server\t6.436s",
+    "ok  \tagent-system-backend/internal/runmgr\t0.495s"
+  ],
+  "output_sha256": "3015a2c860e2066174d3f89da874b63b403192d9aa870b0a3fa4e238f1db9e24",
+  "receipt_sha256": "5d2035b4cc2d543ec86a9fa19b93ed143ff6a637ab275a328827ad5ba02e7b56",
+  "receipt_path": "/home/weichen/.cache/agent-system-dev/evidence/5d2035b4cc2d543ec86a9fa19b93ed143ff6a637ab275a328827ad5ba02e7b56.json"
+}
+```
+
+## Backend 修复结果与本 PR 最终范围
+
+- repair r2 已通过 completed/transport：2ee469011e66b6bedcf6e9d87c8b1c026f7a8cef，仅三个测试文件；主模型审阅与独立重放通过。
+- Backend PR #226 已合入 508288fbed318ec808b1da1145417d062f9e0ce2；精确候选 910d8e5fd20747eebc6e53b5fc0118185cb53765 的 ci/vet-and-test、governance 全部 GATE success；来源 /tmp/pr651-backend-gate.json 与 /tmp/pr651-backend-merged.json。
+- 新版 Backend 同时包含尚待 Dev 组合采用的 O2 依赖，已有独立 PR #653；本规范 PR 不推进 gitlink，以免提前采用另一任务的运行时组合。#651 在最新 main 上重新验证，Backend 修复的已合入与 Dev 已采用分别记录。
+- 交付窗口 mq-dev-20261020-conversation-handoff-01 已在 #518 领取；此前 #652 已释放。当前需 task-sync、闭合任务卡、固定候选并等待三项 GATE。