The choice is unchanged and now better argued: a deployment does not announce
which language its notes are in, so any stemmer picked here is the wrong one
somewhere — and applying the wrong one does not fail loudly, it quietly stops
finding things.
Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
The part that makes a thread work across models: the history goes in front of
what the caller just said, because a client using a thread sends the new turn
rather than the conversation again.
Trimming has three rules, and each is there because the alternative fails
quietly. The oldest stored turns go first, so a conversation that outgrew the
model now serving it stays usable — after a budget fallback that model was not
the caller's choice, and a permanently unusable thread would be a strange way
to punish them for running out of budget. The caller's own messages are never
dropped: answering something they did not ask is worse than refusing. And a
system message is kept wherever it sits, because losing one silently changes
what the model is for while it carries on answering.
A model that declares no context length has nothing trimmed. Guessing a limit
for it would drop turns for no reason and the caller would never learn why the
model forgot.
The body is rebuilt through a map so every field the client sent survives.
Forwarding fields llmgw does not understand is how engine-specific options
reach an engine at all, and a thread must not be what starts dropping them.
An empty history returns the body byte for byte, so a request without a thread
takes exactly the path it took before this existed.
Not yet wired to the request path.
Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
