Workflow tool: structured return value not retrievable after completion notification truncates it

What I observed

After a background Workflow run completed, the completion notification truncated the structured value the script returned (an array of per-stage result objects). The persisted task .output file for the workflow held the run narration/log, not the returned JSON, so the full structured result was not recoverable from it. To find which pipeline stage had failed (an object with "verdict":"fail" among ~13), I had to grep the individual workflow subagent transcripts under subagents/workflows/<runid>/*.jsonl for the field. That works but is fragile and undocumented.

What I expected

The value a Workflow script returns should be persisted to a retrievable file (alongside the run, like the .output narration) so the orchestrating agent can read the complete structured result even when the inline notification is truncated.

Steps to reproduce

1. Run a Workflow (background) whose script returns a large array, e.g. a pipeline(...) over ~13 items where each item resolves to an object containing prose fields (notes/summaries).
2. Let it complete.
3. Observe that the completion notification truncates the returned array, and that the task .output file contains the narration log rather than the returned JSON. The structured result is not directly retrievable.

Context

Tool: Workflow (run in background). Approximate date: 2026-06-07. The workaround (grepping subagents/workflows/<runid>/*.jsonl) recovered the data but should not be necessary.