Description

When a flow produces a large result object (observed at ~1.2MB of JSON), the CLI either truncates the output or crashes with Invalid string length. This affects complex orchestration flows where intermediate results accumulate.

Reproduction

Create a flow that:

1. Calls multiple sub-flows that each return 50-200KB of output
2. Aggregates results into a single buildResult step
3. Execute with one --agent flow execute <key>

Expected: Full JSON result on stdout
Actual: Truncated output or Invalid string length error

Workaround

Write the result to a checkpoint file as the last flow step, then have the parent process read the file instead of relying on stdout:

{
  "id": "writeCheckpoint",
  "type": "file-write",
  "fileWrite": {
    "path": "/tmp/flow-result.json",
    "content": "$.steps.buildResult.output"
  }
}

Suggested Fix

1. Stream large outputs to a temp file and return a reference, or
2. Increase the internal string buffer limit, or
3. Add a --output-file <path> flag for flow execution