# NousResearch/hermes-agent · ACP prompt hang fix: usage/session update blocking

## Open now

- 1 issue, 3 PRs open on GitHub.
- #39245: ACP prompt can hang after final text response when usage_update/session update does not return
- PR #39378: fix(acp): add timeout to usage_update before returning PromptResponse
- PR #51498: fix(acp): wrap usage_update + session_info_update in best-effort so a stalled client cannot wedge prompt()
- PR #82133: fix(acp): queue terminal response before optional usage metadata

These issues and fixes address a bug where ACP's prompt() could hang indefinitely if usage_update or session_info_update calls stalled. Solutions involve timeouts, best-effort wrapping, and reordering terminal response delivery before optional metadata updates.

## TL;DR

- 4 member(s): 1 open issue(s), 0 closed issue(s), 3 open PR(s), 0 merged PR(s), 0 PR(s) closed without merging.
- No fix has been merged to main; one or more PRs were attempted (see below).
- **Recommended:** review the prior/competing PR(s) below. A fix was attempted but not merged; your case may extend or revive that work.

## Maintainer resolution verdict

- Internal-tracker verdict over this cluster's issue members: `unresolved`. 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evidence (`STRUCTURAL_SPANNING`): every member is connected by structural evidence: shared changed files, or a closing/superseded reference.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.

## Open related issues

- #39245: ACP prompt can hang after final text response when usage_update/session update does not return

## Prior & competing PRs

- **#39378: fix(acp): add timeout to usage_update before returning PromptResponse**. open
  - maintainer direction: category `uncategorized`; implication `needs_llm`
  - files: `acp_adapter/server.py`, `tests/acp_adapter/test_acp_commands.py`
- **#51498: fix(acp): wrap usage_update + session_info_update in best-effort so a stalled client cannot wedge prompt()**. open
  - maintainer direction: category `superseded_by_pr`; implication `superseded`; refs `#39378`, `#39245`
  - files: `.gitignore`, `acp_adapter/server.py`, `tests/acp/test_prompt_best_effort_updates.py`
- **#82133: fix(acp): queue terminal response before optional usage metadata**. open
  - maintainer direction: category `uncategorized`; implication `needs_llm`; refs `#39245`
  - files: `acp_adapter/server.py`, `tests/acp/test_server.py`

## Fix status

- No merged fix on record.
- Subsystem: `acp`