fix: deliver plugin-transformed final_response through streaming gate by kenyonxu · Pull Request #29119 · NousResearch/hermes-agent

kenyonxu · 2026-05-20T05:56:08Z

Problem

Plugin hooks registered on transform_llm_output modify the final response AFTER streaming completes. However, three separate suppression points silently discard the transformed content:

ACP adapter (acp_adapter/server.py): not streamed_message guard skips final_response delivery when streaming was used
Gateway suppression (gateway/run.py): _streamed or _content_delivered check suppresses the normal final send entirely
Gateway run_sync() (gateway/run.py): cherry-picks fields from the run_conversation result dict into a new response dict, but omits critical fields

The net effect is that any content appended by a transform_llm_output hook never reaches end users on streaming platforms (Discord, Telegram, ACP, etc.).

Fix (4 coordinated changes)

1. `agent/conversation_loop.py`

Set response_transformed=True when a transform_llm_output hook returns a non-empty string. Expose this as response_transformed in the result dict.

2. `gateway/run.py` — `run_sync()` return dict

Add response_transformed to the cherry-picked fields so the flag survives the gateway's response construction.

3. `gateway/run.py` — suppression check

When response_transformed=True, edit the existing streamed message in-place (via the adapter's edit_message) with the full transformed content, then set already_sent=True. This avoids creating a duplicate message while ensuring the transformed content reaches the client.

4. `gateway/stream_consumer.py`

Expose message_id and accumulated_text as public read-only properties so the gateway can perform the in-place edit.

5. `acp_adapter/server.py`

Remove the not streamed_message guard — the final response (possibly transformed by plugins) should always be delivered to the ACP client.

Test plan

Enable a transform_llm_output plugin that appends text
Send a message via Discord or any streaming platform
Verify the appended text appears in the SAME message (not a duplicate)
Disable the plugin — verify no duplicate messages or extra text

alt-glitch · 2026-05-20T06:08:32Z

This PR includes ~3295 graphify-out/ cache files (2.7M additions, 3300 changed files total) alongside the 5-file core fix. The actual plugin-streaming fix touches acp_adapter/server.py, agent/conversation_loop.py, gateway/run.py, gateway/stream_consumer.py, and a design doc. Please rebase onto current main and remove the graphify-out/ directory from the branch — it appears to be a local analysis artifact that was accidentally committed.

Note: PR #29074 (closed) addressed the ACP-only subset of this same issue. This PR is broader (gateway + ACP + conversation_loop), so it's not a strict duplicate, but please verify the ACP portion doesn't conflict with whatever fix landed from #29074.

…ut hook now visible When streaming is active, streamed_message=True skipped the final_response update, causing plugin hooks like transform_llm_output to be silently invisible. Remove the `not streamed_message` guard so the final response (possibly transformed by plugins) is always delivered to the ACP client.

…s streaming suppression When a transform_llm_output hook modifies final_response after streaming, the gateway was silently discarding the transformed content because streamed=True / content_delivered=True triggered the final-send suppression. Three changes: 1. conversation_loop: set `_response_transformed=True` when a transform_llm_output hook returns a non-empty string, and expose it as `response_transformed` in the result dict. 2. gateway/run: skip the final-send suppression when `response_transformed` is True — the transformed response must reach the client even if streaming already sent the original text. 3. acp_adapter/server: remove `not streamed_message` guard so final_response is always delivered (ACP path fixed separately).

…stale pyc

…turn dict run_sync() cherry-picks fields from the run_conversation result dict into a new response dict for the gateway. response_transformed was missing from the cherry-pick list, so the gateway always saw it as False and suppressed the final send even though a transform_llm_output hook had modified the content.

… response_transformed When a transform_llm_output hook appends content after streaming, the previous fix skipped the final-send suppression which caused the full response to be sent as a NEW message (duplicate). Instead, edit the existing streamed message in-place to append the transformed content, then set already_sent=True. Added stream_consumer.message_id and .accumulated_text public properties.

…ng suppression Document the three-layer suppression bug that prevented plugin-transformed final_response content from reaching users on streaming platforms (Discord, Telegram, ACP). Includes the 5-file coordinated fix and data flow diagram.

kenyonxu · 2026-05-24T09:34:49Z

Thanks for the review!

graphify-out/ cleaned up: Rebased onto latest main and removed all ~3295 graphify-out/ files from the branch history. Also added graphify-out/ to .gitignore to prevent accidental re-commit. The diff is now down to 6 files / 158 lines.
Re: conflict with fix(acp): deliver final_response after streaming — plugin hooks now visible #29074: I checked — fix(acp): deliver final_response after streaming — plugin hooks now visible #29074 was closed without being merged (merged_at is null, merged_by is null). No related fix landed in upstream main. The ACP portion here is the same code that was in the closed fix(acp): deliver final_response after streaming — plugin hooks now visible #29074, so there is no conflict to worry about.

PR #29119 dropped the 'not streamed_message' guard unconditionally so that plugin-transformed responses (transform_llm_output hook) would reach ACP clients. That regressed test_prompt_does_not_duplicate_streamed_final_message: when no transform happened, the streamed text was re-sent as a duplicate final delivery. Tighten the condition to mirror the gateway side: deliver after streaming only when response_transformed=True. Otherwise keep the old guard. Adds test_prompt_delivers_transformed_response_after_streaming so the transformed path stays covered.

…ming Adds a test that fails without the gateway fix, exercising the response_transformed=True branch in _finalize_response: a streamed response whose final text was modified by a transform_llm_output plugin hook must be edit_message'd in place (not duplicate-sent), with already_sent=True so the normal final-send is skipped. Also drops two minor leftovers from the salvaged PR #29119: * accumulated_text property on GatewayStreamConsumer (unused) * duplicate _response_transformed=False inside the hook try block

PR #29119 dropped the 'not streamed_message' guard unconditionally so that plugin-transformed responses (transform_llm_output hook) would reach ACP clients. That regressed test_prompt_does_not_duplicate_streamed_final_message: when no transform happened, the streamed text was re-sent as a duplicate final delivery. Tighten the condition to mirror the gateway side: deliver after streaming only when response_transformed=True. Otherwise keep the old guard. Adds test_prompt_delivers_transformed_response_after_streaming so the transformed path stays covered.

teknium1 · 2026-05-24T11:31:29Z

Merged via PR #31433. Your 4 substantive commits were cherry-picked onto current main with your authorship preserved in git log — see commits 7eb6c7f, 8edeebe, a4ceead, 5cb21e3. Follow-ups (a regression test + a tightening of the ACP guard so non-transformed streams stay single-delivery) added on top. Thanks for the fix!

…ming Adds a test that fails without the gateway fix, exercising the response_transformed=True branch in _finalize_response: a streamed response whose final text was modified by a transform_llm_output plugin hook must be edit_message'd in place (not duplicate-sent), with already_sent=True so the normal final-send is skipped. Also drops two minor leftovers from the salvaged PR NousResearch#29119: * accumulated_text property on GatewayStreamConsumer (unused) * duplicate _response_transformed=False inside the hook try block

PR NousResearch#29119 dropped the 'not streamed_message' guard unconditionally so that plugin-transformed responses (transform_llm_output hook) would reach ACP clients. That regressed test_prompt_does_not_duplicate_streamed_final_message: when no transform happened, the streamed text was re-sent as a duplicate final delivery. Tighten the condition to mirror the gateway side: deliver after streaming only when response_transformed=True. Otherwise keep the old guard. Adds test_prompt_delivers_transformed_response_after_streaming so the transformed path stays covered.