Hermes agentmemory plugin: sync_turn() fails on unexpected keyword argument session_id

[OptionalCoin]

Summary
The Hermes agentmemory plugin’s memory-provider hook signature is too strict for the arguments Hermes passes at runtime. As a result, sync_turn() throws an exception when Hermes includes extra context kwargs such as session_id.
Environment

• Hermes Agent
• agentmemory plugin enabled
• Linux user-service deployment
• Observed with normal CLI conversation turns
  Actual behavior
  Hermes logs repeated warnings like:
  Memory provider 'agentmemory' sync_turn failed: AgentMemoryProvider.sync_turn() got an unexpected keyword argument 'session_id'
  text

Expected behavior

The plugin should accept Hermes-passed context kwargs without failing, or the plugin/runtime contract should be updated so the hook signature matches the actual runtime call.

Root cause

The plugin currently defines:
def sync_turn(self, user: str, assistant: str) -> None:
text
But Hermes calls it with additional keyword arguments, including session_id.
This is a contract mismatch between Hermes and the plugin implementation.

Impact

• Repeated warning spam in logs
• sync_turn does not complete cleanly
• Conversation-turn memory sync may be degraded or skipped
• Extra noise makes real failures harder to spot

Reproduction steps

1. Install and enable the agentmemory plugin in Hermes.
2. Start a Hermes session.
3. Run a normal conversation turn.
4. Check ~/.hermes/logs/agent.log or ~/.hermes/logs/errors.log.

Observed log

Memory provider 'agentmemory' sync_turn failed: AgentMemoryProvider.sync_turn() got an unexpected keyword argument 'session_id'
text

Suggested fix

Update hook methods to tolerate passthrough kwargs from Hermes:
def sync_turn(self, user: str, assistant: str, **kwargs: Any) -> None:
text
It may also be prudent to make other memory-provider hook methods tolerant of extra context kwargs as well, such as:

• prefetch
• queue_prefetch

Local verification

I patched the local plugin by adding **kwargs to the affected methods and then verified:

• Python syntax check passed
• Hermes CLI smoke run completed successfully
• The patched session no longer surfaced the unexpected keyword argument 'session_id' failure

Notes

This appears to be a real runtime compatibility bug, not an installation issue. The plugin loads and activates, but one hook call path is not compatible with the arguments Hermes passes.

[rohitg00]

Thanks @OptionalCoin — confirmed bug, your root-cause analysis nailed it. Strict signature on sync_turn(self, user, assistant) rejecting Hermes's session_id kwarg meant the hook silently failed every single conversation turn, with the warning being the only signal.

Patch is in #252 — adds **kwargs: Any to every memory provider hook in integrations/hermes/__init__.py:

• sync_turn, on_session_end, on_pre_compress, on_memory_write, prefetch, queue_prefetch, shutdown — all now tolerate Hermes's passthrough kwargs.
• Same change applied to the abstract MemoryProvider fallback class used when agent.memory_provider is unavailable at import time, so the contract stays consistent.
• Where Hermes passes session_id, the patch prefers it over the cached self._session_id (in sync_turn, on_session_end, on_pre_compress). Means per-turn observations land on the right session even if Hermes routes the hook through a different conversation than the one the provider was initialized with.

Mind running #252 against your Hermes setup to confirm the fix? Same repro you used locally — install plugin, run a turn, check ~/.hermes/logs/agent.log for the unexpected keyword argument line.

Closing this on merge.

[OptionalCoin]

Yep! I just tested this in a fresh Hermes CLI process against the live agentmemory service, and it passed cleanly.

Result:

• exit code 0
• output: SMOKE_OK
• no stderr
• no unexpected keyword argument 'session_id' error

So the session_id hook-signature issue looks fixed end-to-end on my side.