# NousResearch/hermes-agent · SSE event order errors trigger non-stream fallback

## Open now

- Nothing open on GitHub.

These items address a bug where out-of-order SSE events from custom and Anthropic providers should trigger a fallback to non-streaming mode. The work spans bug identification and fixes across multiple providers.

## TL;DR

- 4 member(s): 0 open issue(s), 1 closed issue(s), 0 open PR(s), 1 merged PR(s), 2 PR(s) closed without merging.
- A fix was merged to main in PR #121554. Verify it addresses your case.
- **Recommended:** read PR #121554 (and any competing PRs below) before filing. Confirm the merged change covers your symptom.

## Maintainer resolution verdict

- Internal-tracker verdict over this cluster's issue members: `resolved` · deciding PR(s): `pr-121554`. This is distinct from the fix status above. Weigh it yourself.

## How this cluster was grouped

- Link evidence (`STRUCTURAL_SPANNING`): every member is connected by structural evidence: shared changed files, or a closing/superseded reference.
- Pairwise link density `0.50`: the share of member pairs that carry a link, counting a structural link in full and a relevance-only link at 0.36. `1.00` means every pair is linked.

## Closed / duplicate issues

- #72833: bug(streaming): custom provider SSE event order error should trigger non-stream fallback

## Prior & competing PRs

- **#121554: fix(anthropic): normalize usage:null streams, non-stream fallback on out-of-order SSE, Messages-shaped partial stubs**. merged to main · fix tier `verified`
  - maintainer direction: category `merged`
  - files: `agent/anthropic_adapter.py`, `agent/chat_completion_helpers.py`, `tests/agent/test_anthropic_stream_fallbacks.py`, `tests/agent/test_streaming.py`
- **#72862: fix(streaming): fall back to non-stream on custom provider SSE order error (#72833)**. closed without merge
  - maintainer direction: category `merged_via`; implication `superseded`; refs `44f6d3bbee`, `#121554`, `#72833`
- **#73125: fix(anthropic): trigger non-stream fallback on SSE event order errors (#72833)**. closed without merge
  - maintainer direction: category `duplicate_of`; implication `duplicate`; refs `#72862`, `#72833`

## Fix status

- Merged to main in PR #121554 (cited above). No release data is tracked. Verify downstream.
- Fix last verified (merged) `2026-09-24`.
- Subsystem: `agent`