Avoid replaying active health operations during polling

src/lib/server/hosts/index.ts

@@ -504,8 +504,12 @@ export function pendingHostOperationRows(hostId: string, lane: OperationLane = '
             AND (kind!='instance.cancel-create' OR ?)
             AND NOT EXISTS (SELECT 1 FROM ec_host_operations cancellation WHERE cancellation.host_id=o.host_id
                 AND cancellation.kind='instance.cancel-create' AND json_extract(cancellation.payload,'$.createOperationId')=o.id)
+            ${lane === 'health' ? "AND (state NOT IN ('accepted','running') OR MAX(updated_at,COALESCE(last_delivered_at,'')) <= ?)" : ''}
             ORDER BY CASE WHEN kind='instance.cancel-create' THEN 0 ELSE 1 END,COALESCE(last_delivered_at,''),created_at,rowid LIMIT ${limit}`)
-            .all(hostId, Number(host.readiness === 'ready' || host.mode === 'draining'), Number(host.inventory.capabilities?.includes('instance.cancel-create') ?? false)) as OperationDeliveryRow[];
+            // A short replay lease avoids handing the idle health lane its busy
+            // sibling's work, but still recovers a lost receipt or agent restart.
+            .all(hostId, Number(host.readiness === 'ready' || host.mode === 'draining'), Number(host.inventory.capabilities?.includes('instance.cancel-create') ?? false),
+                ...(lane === 'health' ? [new Date(Date.now() - 30_000).toISOString()] : [])) as OperationDeliveryRow[];
         const deliveredAt = now();
         for (const operation of rows) database().prepare('UPDATE ec_host_operations SET last_delivered_at=? WHERE id=?').run(deliveredAt, operation.id);
         return rows;

tests/unit/native-hosts.test.ts

@@ -94,11 +94,30 @@ describe('native host enrollment and scoped authentication', () => {
         const query = prepare.mock.calls.map(([sql]) => sql).find(sql => sql.includes('FROM ec_host_operations o WHERE host_id=?'))!;
         prepare.mockRestore();
         // Assert the actual poll's access path, avoiding hardware-dependent timing thresholds.
-        const plan = handle.prepare(`EXPLAIN QUERY PLAN ${query}`).all(api.host.id, 1, 1) as { detail: string }[];
+        const plan = handle.prepare(`EXPLAIN QUERY PLAN ${query}`).all(api.host.id, 1, 1, new Date().toISOString()) as { detail: string }[];
         expect(plan.find(row => row.detail.includes('SEARCH cancellation'))?.detail)
             .toContain('(host_id=? AND kind=?)');
     });
 
+    it.each(['accepted', 'running'])('withholds %s health work and replays its original ID after the recovery lease', async state => {
+        const api = await enrolled();
+        vi.useFakeTimers({ toFake: ['Date'] });
+        const at = Date.now();
+        api.heartbeat(api.host.id, { ...inventory, capabilities: ['operations.health-lane'] });
+        const busy = api.queueHostOperation(api.host.id, 'instance.inspect', {});
+        api.pendingHostOperations(api.host.id, 'health');
+        api.reportHostOperation(api.host.id, busy.id, { state });
+        const next = api.queueHostOperation(api.host.id, 'rcon.execute', { command: 'status' });
+        expect(api.pendingHostOperations(api.host.id, 'health').map(op => op.id)).toEqual([next.id]);
+        api.reportHostOperation(api.host.id, next.id, { state: 'completed' });
+        expect(api.pendingHostOperations(api.host.id, 'health')).toEqual([]);
+        vi.setSystemTime(at + 30_001);
+        expect(api.pendingHostOperations(api.host.id, 'health').map(op => op.id)).toEqual([busy.id]);
+        expect(api.pendingHostOperations(api.host.id, 'health')).toEqual([]);
+        api.reportHostOperation(api.host.id, busy.id, { state: 'unknown' });
+        expect(api.pendingHostOperations(api.host.id, 'health').map(op => op.id)).toEqual([busy.id]);
+    });
+
     it('reserves health delivery while a file backlog is pending and bounds background batches', async () => {
         const api = await enrolled();
         api.heartbeat(api.host.id, { ...inventory, capabilities: ['operations.health-lane'] });