fix(mothership): run workflow tools (run from block, run until block)

[Sg312]

Summary

Fixes run workflow tools
Fixes stream reconnect bug

Type of Change

• Bug fix

Testing

Manual

Checklist

• Code follows project style guidelines
• Self-reviewed my changes
• Tests added/updated and passing
• No new warnings introduced
• I confirm that I have read and agree to the terms outlined in the Contributor License Agreement (CLA)

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1 Skipped Deployment

Project	Deployment	Actions	Updated (UTC)
docs	Skipped		Mar 15, 2026 1:54am

[greptile-apps]

Greptile Summary

This PR fixes two related issues in the Mothership/Copilot feature: broken workflow execution tools (run_workflow, run_from_block, run_workflow_until_block, run_block) and a stream reconnect bug when returning to an in-progress chat.

Key changes:

• handlers.ts: Removes the CLIENT_WORKFLOW_TOOLS special-case in the interactive === false path that was calling waitForToolCompletion. These tools now fall through to fireToolExecution() like any other server-side tool. The concern here is whether the browser's use-chat.ts still fires executeRunToolOnClient for the same event (see inline comment).
• use-chat.ts: Overhauled stream reconnect — instead of a separate useEffect watching activeStreamId that blindly re-fetched from from=0, the reconnect now happens inside the chatHistory effect using a snapshot of buffered events piped into a combined ReadableStream, falling back to a live SSE tail for incomplete streams. processSSEStreamRef and finalizeRef refs are synced each render via useLayoutEffect to avoid stale closures. A new isReconnecting state gates a skeleton overlay during the reconnect phase.
• workflow-execution-utils.ts: Separates JSON.parse from the event switch so a malformed line no longer silently drops the entire batch; converts execution:error from throw to a returned failure result, which is compatible with the existing caller in run-tool-execution.ts.
• route.ts / tasks.ts: The GET /api/copilot/chat response now includes a streamSnapshot (buffered events + status) when a conversationId is present, eliminating an extra round-trip during reconnect.

Confidence Score: 3/5

• Merge with caution — the core fixes look directionally correct but the workflow tool execution path needs verification to rule out duplicate server+client execution.
• The stream reconnect rework is well-structured and the execution:error fix is clean. The main uncertainty is whether removing CLIENT_WORKFLOW_TOOLS from the interactive === false handler causes both fireToolExecution() (server-side) and executeRunToolOnClient (browser-side) to fire for the same tool call, which would trigger two concurrent workflow executions. Additionally, the isReconnecting skeleton condition change in home.tsx drops the !hasMessages guard, potentially flashing a skeleton over already-loaded messages.
• Pay close attention to apps/sim/lib/copilot/orchestrator/sse/handlers/handlers.ts (dual-execution risk) and apps/sim/app/workspace/[workspaceId]/home/hooks/use-chat.ts (reconnect state management).

Important Files Changed

Filename	Overview
apps/sim/lib/copilot/orchestrator/sse/handlers/handlers.ts	Removes the CLIENT_WORKFLOW_TOOLS special-case for interactive === false, eliminating the waitForToolCompletion blocking path; workflow tools now execute server-side via fireToolExecution(). This is the core fix, but may trigger duplicate execution if the browser still receives the forwarded SSE event with ui.clientExecutable = true.
apps/sim/app/workspace/[workspaceId]/home/hooks/use-chat.ts	Significant rework of stream reconnect logic: moved from a standalone useEffect watching activeStreamId to inline reconnect inside the chatHistory effect, using processSSEStreamRef/finalizeRef to avoid stale closures. Adds isReconnecting state and lazy assistant-message creation in flush(). The skeleton condition change in home.tsx (consuming isReconnecting) may flash over existing messages.
apps/sim/app/workspace/[workspaceId]/w/[workflowId]/utils/workflow-execution-utils.ts	Refactors SSE parsing: separates JSON.parse into its own try/catch so parse errors skip only the current event (not the entire event handler). Converts execution:error from throwing an exception to returning a { success: false } result object; this is compatible with the existing callers in run-tool-execution.ts.
apps/sim/app/api/copilot/chat/route.ts	Adds stream snapshot (events + status) to the GET /api/copilot/chat response when chat.conversationId is set. Errors are caught and logged without blocking the main response, and the snapshot is only included if it successfully loaded.
apps/sim/hooks/queries/tasks.ts	Adds StreamSnapshot interface and optional streamSnapshot field to TaskChatHistory; maps chat.streamSnapshot from the API response in fetchChatHistory. Clean, additive change.
apps/sim/app/workspace/[workspaceId]/home/home.tsx	Exposes isReconnecting from useChat and updates the loading skeleton condition to also show during reconnection. The removal of the !hasMessages guard may cause the skeleton to briefly replace already-rendered messages during a reconnect.

Sequence Diagram

sequenceDiagram
    participant Browser
    participant NextAPI as Next.js API
    participant Orchestrator as Orchestrator (handlers.ts)
    participant Go as Go Backend

    Note over Browser,Go: Normal send-message flow
    Browser->>NextAPI: POST /api/copilot/chat
    NextAPI->>Go: Forward message + open SSE stream
    Go-->>Orchestrator: SSE: tool_call (run_workflow, clientExecutable=true)
    
    alt interactive === false (NEW behavior)
        Orchestrator->>Orchestrator: fireToolExecution() → SIM_WORKFLOW_TOOL_HANDLERS
        Orchestrator->>NextAPI: Execute workflow server-side
        Orchestrator-->>Go: markToolComplete (result)
    end
    
    Go-->>NextAPI: SSE forwarded to browser stream
    NextAPI-->>Browser: SSE: tool_call (ui.clientExecutable=true)
    Browser->>Browser: executeRunToolOnClient() ← still triggered!
    Browser->>NextAPI: POST /api/workflows/{id}/execute (client-side)
    Browser->>NextAPI: POST /api/copilot/confirm (reportCompletion → Redis)
    Note over NextAPI: Nobody reads Redis result in new code

    Note over Browser,Go: Stream reconnect flow (NEW)
    Browser->>NextAPI: GET /api/copilot/chat?chatId=X
    NextAPI->>NextAPI: getStreamMeta + readStreamEvents (parallel)
    NextAPI-->>Browser: chat + streamSnapshot{events[], status}
    
    alt snapshot exists & not expired
        Browser->>Browser: Pipe batch events into ReadableStream
        Browser->>NextAPI: GET /api/copilot/chat/stream?from=lastEventId
        NextAPI-->>Browser: Live SSE tail
        Browser->>Browser: processSSEStream(combinedStream)
    else snapshot expired (status=unknown, 0 events)
        Browser->>NextAPI: POST /api/mothership/chat/stop (cleanup)
    end

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Comments Outside Diff (1)

1. apps/sim/lib/copilot/orchestrator/sse/handlers/handlers.ts, line 316-321 (link)

   Potential double execution of workflow tools

   By removing the CLIENT_WORKFLOW_TOOLS guard in the interactive === false path, the server now calls fireToolExecution() → executeToolAndReport → executeToolServerSide → SIM_WORKFLOW_TOOL_HANDLERS.run_workflow (etc.) directly. However, the same SSE tool_call event is forwarded to the browser, where use-chat.ts still checks ui?.clientExecutable and calls executeRunToolOnClient for run_workflow, run_from_block, etc. This means both paths can execute the workflow concurrently — one server-side API call and one client-side API call — resulting in two separate execution runs against the same workflow.

   If ui.clientExecutable is guaranteed to be false when options.interactive === false, this isn't an issue; but if the Go backend sends ui.clientExecutable: true in both modes, the duplicate execution should be explicitly guarded against. It's worth confirming that the Go backend does not set clientExecutable: true on tool events in the non-interactive path, or that isToolAvailableOnSimSide should return false for these tools in that context.

_{Last reviewed commit: 34283b5}