sequenceDiagram
    participant Client as Client Hook
    participant API as Execute Route
    participant Redis as Redis
    participant Engine as Execution Engine
    participant LoopOrch as Loop Orchestrator
    participant WaitHandler as Wait Handler

    Note over Client,WaitHandler: Normal Execution Flow
    Client->>API: POST workflows execute
    API->>API: Generate executionId
    API->>Engine: Start execution with abortController
    Engine->>Engine: Initialize useRedisCancellation flag
    
    alt Has Loop Execution
        Engine->>LoopOrch: Execute iteration
        LoopOrch->>Redis: isExecutionCancelled
        Redis-->>LoopOrch: false
        LoopOrch->>Engine: Continue iteration
    end
    
    alt Has Wait Block
        Engine->>WaitHandler: Execute wait block
        WaitHandler->>WaitHandler: Start sleep with 500ms interval
        WaitHandler->>Redis: isExecutionCancelled
        Redis-->>WaitHandler: false
        WaitHandler-->>Engine: Wait completed
    end

    Note over Client,WaitHandler: Cancellation Flow
    Client->>Client: User clicks cancel
    Client->>API: POST cancel execution
    API->>Redis: markExecutionCancelled
    Redis-->>API: Success
    API-->>Client: success true
    
    Client->>API: AbortController abort
    API->>API: Stream cancel callback
    API->>Redis: markExecutionCancelled
    API->>API: abortController abort

    Note over Engine,WaitHandler: Engine Detects Cancellation
    alt Engine Main Loop Check
        Engine->>Engine: checkCancellation 500ms throttle
        Engine->>Redis: isExecutionCancelled
        Redis-->>Engine: true
        Engine->>Engine: Set cancelledFlag true
        Engine-->>API: status cancelled
    end
    
    alt During Wait Block
        WaitHandler->>Redis: isExecutionCancelled
        Redis-->>WaitHandler: true
        WaitHandler->>WaitHandler: cleanup and resolve false
        WaitHandler-->>Engine: status cancelled
    end
    
    alt During Loop Iteration
        LoopOrch->>Redis: isExecutionCancelled
        Redis-->>LoopOrch: true
        LoopOrch-->>Engine: Exit loop result
    end

    API->>Client: SSE event execution cancelled
    
    Note over Client,WaitHandler: Fallback Without Redis
    alt No Redis Available
        Client->>API: AbortController abort
        API->>API: abortController abort
        Engine->>Engine: Check abortSignal aborted
        Engine->>Engine: Set cancelledFlag true
        Engine-->>API: status cancelled
    end