Every conversation-affinity hint Hermes sends is derived from the PHYSICAL
session id: prompt_cache_key on both OpenAI-wire transports, OpenRouter's and
Nous Portal's sticky session_id, and xAI's x-grok-conv-id. A host that mints
one physical session per RESPONSE re-keys all four on every reply, so the
conversation never lands back on the routing bucket it just warmed (#96811).
Two hosts do exactly that. Hermes Studio's group chat mints
gc_run_<room>_<profile>_<name>_<uuid4hex> per reply and destroys it after,
and POST /v1/responses with client-managed history mints str(uuid4()) per
request — while parsing X-Hermes-Session-Key one screen earlier and handing
it to the agent.
Hermes must not infer the logical conversation from the id's syntax: that
rule merges independent client-supplied ids and Studio members truncated past
its 96-character boundary (the #79017 failure class). It does not have to.
gateway_session_key is already the "stable per-chat key" built by
gateway.session.build_session_key from that header, and branching
deliberately does not key off it. The affinity path simply never consulted it.
- agent/prompt_cache_scope.py: declared_conversation_scope() resolves the key
into gwk_<sha256[:24]> and outranks the lineage walk (it is stable across
rotation AND across per-response ids). Hashed because, unlike a session id,
the key embeds platform/chat/user identifiers and leaves the process
verbatim as a sticky id and as x-grok-conv-id.
- agent/portal_tags.py: a separate ambient scope for ROUTING, published only
when a host declared one. The providers read the attribution id when it is
unset, so delegate trees keep sharing their parent's sticky key and every
host that keeps one id per conversation is byte-identical to before.
- hermes_state.py: is_explicit_fork_child() — the public view of the marker
rules that keep /branch children, delegate subagents and tool children off
their parent's chat key. Background-review forks clone the live runtime, so
_persist_disabled excludes them for the same reason (#79161).
Refs #96570Fixes#96811
65672e3a93