# NousResearch/hermes-agent · ACP session model validation and error reporting

## Open now

- Nothing open on GitHub.

These items address a bug where invalid model IDs were silently accepted in ACP session/set_model, and introduce fixes to properly reject invalid selections and surface meaningful error causes.

## TL;DR

- 3 member(s): 0 open issue(s), 1 closed issue(s), 0 open PR(s), 1 merged PR(s), 1 PR(s) closed without merging.
- A fix was merged to main in PR #115810. Verify it addresses your case.
- **Recommended:** read PR #115810 (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-115810`. 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evidence (`STRUCTURAL_SPANNING`): every member is connected by structural evidence: shared changed files, or a closing/superseded reference.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 `0.67`: 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

- #72439: \[Bug\]: ACP session/set_model accepts any model ID, and the next turn fails as a silent end_turn

## Prior & competing PRs

- **#115810: fix(acp): rejected session/set_model reports invalid params and a failed rebuild keeps the session and shows its real cause (#72439, #91090, salvage #72579)**. merged to main · fix tier `verified`
  - maintainer direction: category `merged`
  - files: `acp_adapter/server.py`, `acp_adapter/session.py`, `tests/acp_adapter/test_acp_dashboard_model_switch_validation.py`, `tests/acp_adapter/test_session.py`
- **#72579: fix(acp): reject invalid session model selections**. closed without merge
  - maintainer direction: category `merged_via`; implication `superseded`; refs `d45fd1aa31e5`, `#115810`, `#72439`, `#91090`, `#72579`

## Fix status

- Merged to main in PR #115810 (cited above). No release data is tracked. Verify downstream.
- Fix last verified (merged) `2026-09-19`.
- Subsystem: `acp`