diff --git a/docs/agent-coordination.md b/docs/agent-coordination.md
index 3fad449dc..0a1b52358 100644
--- a/docs/agent-coordination.md
+++ b/docs/agent-coordination.md
@@ -231,9 +231,8 @@ The surface, by scope:
   only. Granting project_tasks also makes the agent a project member.
   `POST .../tasks/{id}/claimable` is also reachable, but LEAD-only: the
   route (`_authorize_project_lead`) refuses a plain project_tasks worker.
-  It toggles only the `claimable` label (the fleet-pickup flag), preserving
-  every other label, so it does not widen the scope into free field edits
-  (cf. PATCH).
+  It adds/removes the `claimable` label in place, preserving all other labels,
+  so it does not widen the scope into free field edits (cf. PATCH).
   `POST .../tasks/{id}/unquarantine` is also reachable, but LEAD-only: the
   route (`_authorize_project_lead`) refuses a plain project_tasks worker.
   It returns a quarantined card to the open pool and clears its strikes.
diff --git a/tests/test_task_store.py b/tests/test_task_store.py
index 61331f44f..649469edd 100644
--- a/tests/test_task_store.py
+++ b/tests/test_task_store.py
@@ -344,6 +344,26 @@ async def test_held_task_none_after_close(tmp_path):
     await s.close()
 
 
+@pytest.mark.asyncio
+async def test_claim_after_close_and_reopen(tmp_path):
+    """Red-first: claim -> close -> reopen -> claim by another worker must succeed after fix.
+    
+    This test verifies that reopen_task properly clears claimed_by/claimed_at,
+    making a task claimable again after it was claimed, closed, and reopened.
+    """
+    s = await _store(tmp_path)
+    task = await s.create_task("prj-1", "Task", "alice")
+    await s.claim_task(task["id"], "worker-1")
+    await s.close_task(task["id"], "worker-1")
+    await s.reopen_task(task["id"], "alice")
+    ok = await s.claim_task(task["id"], "worker-2")
+    assert ok is True
+    fetched = await s.get_task(task["id"])
+    assert fetched["claimed_by"] == "worker-2"
+    assert fetched["status"] == "claimed"
+    await s.close()
+
+
 @pytest.mark.asyncio
 async def test_update_task_title(tmp_path):
     s = await _store(tmp_path)
@@ -620,3 +640,54 @@ async def test_quarantine_claimed_task_records_actual_from_status(tmp_path):
     finally:
         await s.close()
         await audit.close()
+
+
+@pytest.mark.asyncio
+async def test_quarantine_unclaimed_task_records_from_status_open(tmp_path):
+    """Open-path assertion: unclaimed task -> audit from_status='open'.
+
+    This test verifies that quarantine_task records from_status='open' when
+    called on an unclaimed task, complementing the existing claimed-task test.
+    """
+    audit = BoardAuditLog(tmp_path / "audit.db")
+    await audit.init()
+    s = ProjectTaskStore(tmp_path / "tasks.db", audit=audit)
+    await s.init()
+    try:
+        task = await s.create_task("prj-1", "Task", "alice")
+        ok = await s.quarantine_task(task["id"], "system")
+        assert ok is True
+        history = await audit.history(task["id"])
+        quarantined = [h for h in history if h["event"] == "task.quarantined"]
+        assert len(quarantined) == 1
+        assert quarantined[0]["from_status"] == "open"
+    finally:
+        await s.close()
+        await audit.close()
+
+
+@pytest.mark.asyncio
+async def test_quarantine_after_reopen_records_from_status_open(tmp_path):
+    """Quarantine-after-reopen records from_status='open'.
+
+    This test verifies that quarantine_task records from_status='open' when
+    called on a reopened task (that was previously claimed, closed, and reopened).
+    """
+    audit = BoardAuditLog(tmp_path / "audit.db")
+    await audit.init()
+    s = ProjectTaskStore(tmp_path / "tasks.db", audit=audit)
+    await s.init()
+    try:
+        task = await s.create_task("prj-1", "Task", "alice")
+        await s.claim_task(task["id"], "worker-1")
+        await s.close_task(task["id"], "worker-1")
+        await s.reopen_task(task["id"], "alice")
+        ok = await s.quarantine_task(task["id"], "system")
+        assert ok is True
+        history = await audit.history(task["id"])
+        quarantined = [h for h in history if h["event"] == "task.quarantined"]
+        assert len(quarantined) == 1
+        assert quarantined[0]["from_status"] == "open"
+    finally:
+        await s.close()
+        await audit.close()