Bug Description

post_llm_call hooks can return a replacement response, but the override is currently applied after session persistence.

This means the user-facing final_response can differ from the assistant message stored in result["messages"], the SQLite session DB, and the JSON session log. On the next turn or after resuming the session, Hermes replays the original model response instead of the hook-modified response.

This creates inconsistent behavior for plugins that use post_llm_call for response post-processing, rendering, policy transforms, or persona/style shaping.

Steps to Reproduce

1. Register a post_llm_call hook that returns a replacement response:

def on_post_llm_call(**kwargs):
    return {"response": "patched response"}

ctx.register_hook("post_llm_call", on_post_llm_call)

2. Run a normal conversation turn where the model produces a response, for example:

original response

3. Observe the returned/displayed final_response.

4. Inspect any of the following:

• result["messages"]
• the persisted session transcript
• the SQLite session DB
• the next turn's replayed conversation context
• a resumed session

Expected Behavior

If post_llm_call supports response overrides, the overridden response should be applied consistently to the completed assistant turn.

The following should all agree:

• returned result["final_response"]
• last assistant message in result["messages"]
• persisted session DB / JSON session log
• next-turn conversation replay
• resumed session transcript

Alternatively, if post_llm_call overrides are intended to be display-only, this should be documented explicitly to avoid plugin authors assuming durable response mutation.

Actual Behavior

The hook override affects the returned user-facing final_response, but does not update the already-persisted assistant message.

Current order is effectively:

self._persist_session(messages, conversation_history)

_post_results = invoke_hook("post_llm_call", ...)
for r in _post_results:
    final_response = ...

As a result:

• the user may see "patched response"
• result["messages"] still contains "original response"
• persisted history still contains "original response"
• the next turn uses "original response" as prior assistant context

Affected Component

CLI (interactive chat), Agent Core (conversation loop, context compression, memory)

Messaging Platform (if gateway-related)

No response

Debug Report

Report     https://paste.rs/pK9p0
  agent.log  https://paste.rs/N7B6x

Operating System

ubuntu 24.04

Python Version

No response

Hermes Version

No response

Additional Logs / Traceback (optional)

Root Cause Analysis (optional)

No response

Proposed Fix (optional)

No response

Are you willing to submit a PR for this?

• I'd like to fix this myself and submit a PR