fix(workflows): keep long-running calls active

[waleedlatif1]

Summary

• keep long workflow and MCP calls active with negotiated heartbeat streams while preserving existing JSON responses
• preserve cancellation, admission, and execution ID ownership across streamed runs and improve CLI transport diagnostics
• document the streamed workflow response and configure the AWS example for long-lived connections

Type of Change

• Bug fix

Testing

• Full lint and 46-audit suite
• App and CLI type checks
• 148 workflow and MCP tests
• 932 CLI tests
• OpenAPI, docs manifest, CLI build, and strict Helm validation

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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Project	Deployment	Actions	Updated
docs	Ready	Preview	Sep 8, 2026 2:05am UTC

[waleedlatif1]

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[greptile-apps]

Greptile Summary

This PR adds negotiated heartbeat transports for long-running workflow and MCP calls while retaining ordinary JSON behavior for clients that do not opt in. It also propagates cancellation and execution ownership through streamed runs, adds shared media-type/SSE/NDJSON utilities, improves CLI transport diagnostics, updates the CLI login method interface, and documents the new workflow response format.

• Adds NDJSON heartbeat and terminal-result framing for synchronous workflow execution.
• Adds SSE keepalives for MCP and workflow event streams.
• Preserves admission tickets and execution-ID claims until streamed runs settle.
• Adds CLI parsing and fallback support for streamed and legacy workflow responses.
• Correctly resolves all three previous review findings, including direct SSE-helper imports.

Confidence Score: 5/5

The PR appears safe to merge because no actionable new failure or outstanding previous finding remains.

The recent changes fully remove the non-barrel SSE-helper re-export and update consumers to import directly from the shared source. The earlier media negotiation and CLI error-translation findings are also covered by exact positive-quality parsing and translated streamed-run errors, respectively. No new blocking or non-blocking issue was established.

Important Files Changed

Filename	Overview
apps/sim/app/api/v2/workflows/[workflowId]/execute/route.ts	Negotiates NDJSON result streams, emits heartbeats, and transfers admission-ticket ownership until execution settles.
apps/sim/lib/workflows/executor/execute-service.ts	Adds pending synchronous execution results with cancellation and deferred execution-ID claim settlement.
apps/sim/app/api/mcp/serve/[serverId]/route.ts	Adds negotiated SSE keepalives and cancellation propagation for long-running MCP tool calls.
apps/sim/lib/workflows/streaming/streaming.ts	Keeps existing workflow SSE connections active with periodic comment frames and lifecycle cleanup.
packages/sim-cli/src/commands/protocol/workflow-run-follow.ts	Consumes heartbeat-delimited workflow results while retaining compatibility with legacy JSON responses and CLI error translation.
packages/sim-cli/src/http/ndjson.ts	Introduces incremental NDJSON parsing with malformed-data handling and reader cleanup.
apps/sim/lib/core/utils/media-types.ts	Implements exact positive-quality media-type negotiation, including explicit rejection and malformed parameter handling.
packages/sim-cli/src/commands/auth.ts	Replaces legacy login flow flags with explicit OAuth and API-key method selection.

Sequence Diagram

sequenceDiagram
  participant Client
  participant Route as Workflow/MCP Route
  participant Executor
  Client->>Route: Request with streaming Accept type
  Route->>Executor: Start execution with cancellation signal
  Route-->>Client: Immediate heartbeat
  loop Every 15 seconds
    Route-->>Client: Heartbeat/keepalive
  end
  Executor-->>Route: Terminal result
  Route-->>Client: Final NDJSON or SSE message
  Route->>Route: Release admission and execution ownership

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_{Reviews (4): Last reviewed commit: "refactor(streaming): import SSE helpers ..." | Re-trigger Greptile}

[waleedlatif1]

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