Back-to-back cache warms update a single 'Cache warmed: $<total>' line with the cumulative cost instead of adding one line per warm. Each warm is still persisted as its own usage entry.
Anthropic can keep a conversation on the server (message threads beta).
A request can then continue from the previous reply and send only the
new messages, instead of the whole history every turn.
pi uses this when a session id is set and caching is on. It still builds
the full request, compares it with the previous one, and only sends the
new part if nothing earlier changed.
- Default: on only for the anthropic provider on api.anthropic.com.
Gateways that drop unknown fields would lose the conversation.
Override with compat.supportsMessageThreads.
- If the server rejects a continuation, pi resends the full request
as a new thread. Other errors turn threads off for the session.
- New option StreamOptions.disableContinuation. The cache warmer sets
it so warm requests don't replace the session's thread.
- cleanupSessionResources(sessionId) frees a session's thread state.
